Update CHANGELOG.md

Release v1.2.6
Mark variables captured by modules as generated
2016-10-29 10:40:53 +02:00 · 2016-06-06 15:26:56 +02:00 · 2016-06-06 15:18:56 +02:00 · 2016-06-03 01:51:52 +02:00 · 2016-06-03 01:19:35 +02:00 · 2016-06-03 00:31:31 +02:00
609 changed files with 41660 additions and 114259 deletions
@@ -1,18 +0,0 @@
-version: 1-{branch}+{build}
-
-build_script:
-  - cmd: C:\MinGW\msys\1.0\bin\make
-  - cmd: rmdir /s /q .git
-before_test:
-  - cmd: set PATH=%PATH%;C:\Program Files\erl8.3\erts-8.3\bin
-test_script:
-  - cmd: C:\MinGW\msys\1.0\bin\make --keep-going test_windows
-
-environment:
-  ELIXIR_ASSERT_TIMEOUT: 2000
-
-matrix:
-  allow_failures:
-    - platform: x86
-    - platform: x64
-    - platform: Any CPU
@@ -1,17 +0,0 @@
-[
-  inputs: [
-    "lib/*/{lib,unicode,test}/**/*.{ex,exs}",
-    "lib/*/mix.exs"
-  ],
-
-  locals_without_parens: [
-    # Formatter tests
-    assert_format: 2,
-    assert_format: 3,
-    assert_same: 1,
-    assert_same: 2,
-
-    # Errors tests
-    assert_eval_raise: 3
-  ]
-]
@@ -1,13 +1,17 @@
-/doc/
-/lib/*/ebin/
-/lib/*/_build/
-/lib/*/tmp/
+/doc
+/ebin
+/lib/*/ebin/*
+/lib/*/tmp
+/lib/elixir/src/*_lexer.erl
 /lib/elixir/src/*_parser.erl
-/lib/elixir/test/ebin/
+/lib/elixir/src/elixir.app.src
+/lib/elixir/test/ebin
 /man/elixir.1
 /man/iex.1
+/rel/elixir
 /Docs-v*.zip
 /Precompiled-v*.zip
 /.eunit
+/.release
 .elixir.plt
 erl_crash.dump
@@ -1,44 +1,15 @@
-language: bash
+language: erlang
+
+otp_release:
+  - 18.0
+
 sudo: false

-env:
-  global:
-    - ELIXIR_ASSERT_TIMEOUT=2000
-  matrix:
-    - OTP_RELEASE=OTP-19.0
-    - OTP_RELEASE=OTP-19.1
-    - OTP_RELEASE=OTP-19.2
-    - OTP_RELEASE=OTP-19.3
-    - OTP_RELEASE=OTP-20.0
-    - OTP_RELEASE=OTP-20.1
-    - OTP_RELEASE=OTP-20.2
-    - OTP_RELEASE=OTP-20.3
-    - OTP_RELEASE=OTP-21.0
-    - OTP_RELEASE=maint
-    - OTP_RELEASE=master
-
-matrix:
-  fast_finish: true
-  allow_failures:
-    - env: OTP_RELEASE=maint
-    - env: OTP_RELEASE=master
-
-install:
-  - wget -O otp.tar.gz https://repo.hex.pm/builds/otp/ubuntu-14.04/${OTP_RELEASE}.tar.gz
-  - mkdir -p otp
-  - tar zxf otp.tar.gz -C otp --strip-components=1
-  - otp/Install -minimal $(pwd)/otp
-  - PATH=$(pwd)/otp/bin:$PATH
-
-script:
-  - make compile
-  - rm -rf .git
-  - make test
-  - dialyzer -pa lib/elixir/ebin --build_plt --output_plt elixir.plt --apps lib/elixir/ebin/elixir.beam lib/elixir/ebin/Elixir.Kernel.beam
+script: "make compile && rm -rf .git && make test"

 notifications:
+  irc: "irc.freenode.org#elixir-lang"
  recipients:
-    - jose.valim@gmail.com
+    - jose.valim@plataformatec.com.br
    - eric.meadows.jonsson@gmail.com
-    - lexmag@me.com
-    - an.leopardi@gmail.com
+
@@ -1,310 +1,282 @@
-# Changelog for Elixir v1.7
+# Changelog for Elixir v1.2

-Elixir v1.7 is the last release to support Erlang/OTP 19. We recommend everyone to migrate to Erlang/OTP 20+.
+v1.2 brings enhancements, bug fixes, performance improvements and more
+into Elixir. Elixir v1.2 relies on many features in Erlang 18, requiring
+at least Erlang 18+. Upgrading to Erlang 18 is therefore necessary before
+upgrading Elixir.

-## Documentation metadata
+## Erlang 18 support

-Elixir v1.7 implements [EEP 48](http://erlang.org/eep/eeps/eep-0048.html). EEP 48 aims to bring documentation interoperability across all languages running on the Erlang VM. The documentation format proposed by EEP 48 also supports metadata, which is now fully exposed to Elixir developers:
+We have brought many features specific to Erlang 18. Here are the highlights:

-```elixir
-@moduledoc "A brand new module"
-@moduledoc authors: ["Jane", "Mary"], since: "1.4.0"
-```
+  * Maps can now scale from dozens to millions of keys. Therefore, usage of
+    the modules `Dict` and `HashDict` is now discouraged and will be
+    deprecated in future releases, instead use `Map`. Similarly, `Set` and
+    `HashSet` will be deprecated in favor of `MapSet`
+  * Compilation times are faster due to improvements in both the Elixir and
+    Erlang compilers
+  * Dialyzer now emits less false negative warnings thanks to new annotations
+    available in the Erlang compiler

-Passing metadata is supported on `@doc`, `@moduledoc` and `@typedoc`.
+## Language improvements

-To access the new documentation format, developers should use `Code.fetch_docs/1`. The old documentation format is no longer available and the old `Code.get_docs/2` function will return `nil` accordingly.
+This release includes four notable language improvements:

-Tools like IEx and ExDoc have been updated to leverage the new format and show relevant metadata to users. While Elixir allows any metadata to be given, those tools currently exhibit only `:deprecated` and `:since`. Other keys may be shown in the future.
+  * The addition of multi aliases/imports/require:

-## The `__STACKTRACE__` construct
+        alias MyApp.{Foo, Bar, Baz}

-Erlang/OTP 21.0 introduces a new way to retrieve the stacktrace that is lexically scoped and no longer relies on side-effects like `System.stacktrace/0` does. Before one would write:
+  * Support for variables in map keys:

-```elixir
-try do
-  ... something that may fail ...
-rescue
-  e ->
-    log(e, System.stacktrace())
-    reraise(e, System.stacktrace())
-end
-```
+        %{key => value}

-In Elixir v1.7, this can be written as:
+  * Support for the pin operator in map keys and function clauses:

-```elixir
-try do
-  ... something that may fail ...
-rescue
-  e ->
-    log(e, __STACKTRACE__)
-    reraise(e, __STACKTRACE__)
-end
-```
+        %{^key => value} = %{key => value}
+        fn ^key -> :ok end

-This change may also yield performance improvements in the future, since the lexical scope allows us to track precisely when a stacktrace is used and we no longer need to keep references to stacktrace entries after the `try` construct finishes.
+  * Addition of the `with` special form to match on multiple expressions:

-Other parts of the exception system have been improved. For example, more information is provided in certain occurrences of `ArgumentError`, `ArithmeticError` and `KeyError` messages.
+        with {:ok, contents} <- File.read("my_file.ex"),
+             {res, binding} <- Code.eval_string(contents),
+             do: {:ok, res}

-## Erlang/OTP logger integration
+These improvements aim to make the language more consistent and expressive.

-Erlang/OTP 21 includes a new `:logger` module. Elixir v1.7 fully integrates with the new `:logger` and leverages its metadata system. The `Logger.Translator` mechanism has also been improved to export metadata, allowing custom Logger backends to leverage information such as:
+## Getting started experience

-  * `:crash_reason` - a two-element tuple with the throw/error/exit reason as first argument and the stacktrace as second
+While we were improving the language, we also improved both the parser and
+compiler to be even more aware of language constructs, emitting warnings
+on common pitfalls like when piping to expressions without parentheses or
+when defining unsafe variables.

-  * `:initial_call` - the initial call that started the process
+We have also introduced the `i/1` helper in IEx, which allows developers
+to retrieve information about any data type. This will help newcomers
+explore the language values while providing experienced developers with
+crucial information about the value they are introspecting.

-  * `:registered_name` - the process registered name as an atom
+## Workflow improvements

-We recommend Elixir libraries that previously hooked into Erlang's `:error_logger` to hook into `Logger` instead, in order to support all current and future Erlang/OTP versions.
+Umbrella applications are now able to share both build and configuration files.
+This aims to drastically reduce compilation times in umbrella projects by
+adding the following configuration to each umbrella app's `mix.exs` file:

-## Other Logger improvements
+    build_path: "../../_build",
+    config_path: "../../config/config.exs",

-Previously, Logger macros such as `debug`, `info`, and so on would always evaluate their arguments, even when nothing would be logged. From Elixir v1.7, the arguments are only evaluated when the message is logged.
+Finally, Mix will now consolidate protocols by default as we are now able to
+consolidate in parallel and cache the consolidation results, providing the
+best performance across all environments without affecting compilation times.
+The only downside of this change is that, if you have been implementing
+protocols exclusively as part of your test suite, inside the `test` directory,
+those won't be picked up as it happens after compilation. For such cases,
+consolidation can be disabled by setting `consolidate_protocols: false` in
+the project config.

-The Logger configuration system also accepts a new option called `:compile_time_purge_matching` that allows you to remove log calls with specific compile-time metadata. For example, to remove all logger calls from application `:foo` with level lower than `:info`, as well as remove all logger calls from `Bar.foo/3`, you can use the following configuration:
+These are great additions on top of the faster compilation times we have
+achieved when migrating to Erlang 18.

-```elixir
-config :logger,
-  compile_time_purge_matching: [
-    [application: :foo, level_lower_than: :info],
-    [module: Bar, function: "foo/3"]
-  ]
-```
+## Rebar 3 support

-## ExUnit improvements
+With Rebar 3 gaining more adoption in the Erlang community, Mix is
+now able to fetch and compile Rebar 3 dependencies. This feature is currently
+experimental and therefore opt-in: if you have a Rebar 3 dependency, you can
+ask Mix to use Rebar 3 to compile it by passing the `manager: :rebar3` option.
+Once configured, Mix will prompt you to install Rebar 3 if it is not yet
+available.

-ExUnit has also seen its own share of improvements. Assertions such as `assert some_fun(arg1, arg2, arg3)` will now include the value of each argument in the failure report:
-
-```
-  1) test function call arguments (TestOneOfEach)
-     lib/ex_unit/examples/one_of_each.exs:157
-     Expected truthy, got false
-     code: assert some_vars(1 + 2, 3 + 4)
-     arguments:
-
-         # 1
-         3
-
-         # 2
-         7
-
-     stacktrace:
-       lib/ex_unit/examples/one_of_each.exs:158: (test)
-```
-
-Furthermore, failures in doctests are now colored and diffed.
-
-On the `mix test` side of things, there is a new `--failed` flag that runs all tests that failed the last time they ran. Finally, coverage reports generated with `mix test --cover` include a summary out of the box:
-
-```
-Generating cover results ...
-
-Percentage | Module
-----------|--------------------------
-   100.00% | Plug.Exception.Any
-   100.00% | Plug.Adapters.Cowboy2.Stream
-   100.00% | Collectable.Plug.Conn
-   100.00% | Plug.Crypto.KeyGenerator
-   100.00% | Plug.Parsers
-   100.00% | Plug.Head
-   100.00% | Plug.Router.Utils
-   100.00% | Plug.RequestId
-       ... | ...
-----------|--------------------------
-    77.19% | Total
-```
-
-## v1.7.4 (2018-10-24)
+## v1.2.6 (2016-06-06)

 ### 1. Enhancements

-#### Elixir
-
-  * [Kernel] Expand `left..right` at compile time in more cases, which leads to improved performance under different scenarios, especially on `x in left..right` expressions
-
-#### Mix
-
-  * [mix deps.loadpaths] Add `--no-load-deps` flag. This is useful for Rebar 3 compatibility
+  * [Kernel] Support Erlang 19
+  * [Kernel] Supported generated: true in the `quote` special form

 ### 2. Bug fixes

-#### Elixir
+  * [Path] Fix a bug in path join with "/" followed by empty segments
+  * [String] Fix a bug in NFD normalization when followed by one-byte sized graphemes
+  * [Typespec] Correctly support `<<_::size, _::_*unit>>` syntax

-  * [Calendar] Fix for converting from negative iso days on New Year in a leap year
-  * [Kernel] Ensure `@spec`, `@callback`, `@type` and friends can be read accordingly
-  * [Module] Avoid warnings when using Module.eval_quoted in the middle of existing definitions
-
-#### Mix
-
-  * [mix archive.build] Unload previous archive versions before building
-  * [mix format] Expand paths so mix format `path\for\windows.ex` works
-  * [mix test] Ensure that `--cover` displays correct coverage in an umbrella app
-
-## v1.7.3 (2018-08-24)
+## v1.2.5 (2016-04-30)

 ### 1. Bug fixes

-#### ExUnit
+  * [Logger] Stringify truncated function data in Logger
+  * [Logger] Ensure poorly formatted char data can also be logged by using the replacement character "�" (diamond question mark)
+  * [Mix] Do not assume `@impl` is always a list
+  * [String] Fix bugs in `String.replace_*` functions where it would not include the accumulated value for certain replacements

-  * [ExUnit.Assertions] Do not attempt to expand `try/1` as it is a special form
+## v1.2.4 (2016-04-01)

-#### Mix
+### 1. Enhancements

-  * [mix compile.app] Do not include applications with `runtime: false` as a runtime dependency for applications coming from Hex
+  * [Mix] Add `:archives` configuration to `def project` that allows projects to list archive dependencies. `--no-archives-check` (as well as `--no-deps-check`) will disable the archive check. The `:archives` option is not checked for dependencies.
+  * [Mix] Add `deps.precompile` task as hook
+  * [Mix] Support `--include-children` in `mix deps.compile` option
+  * [String] Update version of the Unicode database to 8.0.0

-## v1.7.2 (2018-08-05)
+### 2. Bug fixes

-### 1. Bug fixes
+  * [Application] Ensure `spec/2` returns nil for unknown applications
+  * [Integer] Fix a possible binary leak in `parse/1`
+  * [Mix] Purge Erlang modules on recompilation
+  * [String] Ensure `split/1` does not break on non-breakable whitespace
+  * [String] Ensure NFC and NFD normalization pass all of Unicode 8.0.0 tests
+  * [Version] Allow dots in build info for versions in `Version.parse/1`

-#### Elixir
+## v1.2.3 (2016-02-21)

-  * [DateTime] Take negative years into account in `DateTime.from_iso8601/1`
-  * [Kernel] Do not emit warnings for repeated docs over different clauses due to false positives
+### 1. Enhancements

-#### Mix
+  * [Base] Add `:ignore` and `:padding` option to encoding/decoding functions
+  * [Mix] Add `Mix.Projects.deps_paths` that returns the dependencies path as a map

-  * [mix compile] Properly mark top-level dependencies as optional and as runtime. This fixes a bug where Mix attempted to start optional dependencies of a package when those optional dependencies were not available
-  * [mix compile] Avoid deadlock when a config has a timestamp later than current time
-  * [mix help] Show task and alias help when both are available
-  * [mix test] Do not fail suite if there are no test files
+### 2. Bug fixes

-## v1.7.1 (2018-07-26)
+  * [ExUnit] Do not provide negative line numbers without generated annotation (for compatibility with Erlang 19)
+  * [Mix] Reject non fullfilled optional dependencies later on in the convergence resolution for proper dependency sorting
+  * [String] Fix incomplete data trimming on both `String.replace_trailing` and `String.rstrip`
+  * [String] Attach debug_info back into Unicode modules for Dialyzer support

-### 1. Bug fixes
+## v1.2.2 (2016-01-31)

-#### Elixir
+### 1. Enhancements

-  * [Calendar] Work-around a Dialyzer bug that causes it to loop for a long time, potentially indefinitely
+  * [Kernel] Support `@compile {:autoload, false}` to disable automatic loading after compilation

-## v1.7.0 (2018-07-25)
+### 2. Bug fixes
+
+  * [ExUnit] Raise if trying to override reserved tag in `setup` blocks
+  * [Mix] Ensure retrieve compile manifests do fail if some compilers are not yet available
+  * [Mix] Automatically merge managers according to the mix > rebar3 > rebar > make order
+  * [Mix] Force recompilation if dependency was recently fetched
+
+## v1.2.1 (2016-01-14)
+
+### 1. Enhancements
+
+  * [IEx] Support remote pids/ports with IEx helper `i/1`
+  * [Protocol] Warn when `defimpl` is called for a consolidated protocol
+
+### 2. Bug fixes
+
+  * [ExUnit] Ensure `assert` macros can be used from quoted code
+  * [ExUnit] Do not warn in match assertion if variable is reused in pattern
+  * [Macro] Fix a bug in `Macro.to_string/1` where a remote function could be accidentally interpreted as a sigil
+  * [Mix] Ensure dependencies are properly skipped when `--only` option is given to `mix deps.get`
+
+## v1.2.0 (2016-01-01)

 ### 1. Enhancements

 #### Elixir

-  * [Calendar.ISO] Support negative dates in `Calendar.ISO`
-  * [Calendar] Add `Calendar.months_in_year/1` callback
-  * [Code] Add `Code.compile_file/2` that compiles files without leaving footprints on the system
-  * [Code] Add `Code.purge_compiler_modules/0` that purges any compiler module left behind. This is useful for live systems dynamically compiling code
-  * [Code] Add `Code.fetch_docs/1` that returns docs in the [EEP 48](http://erlang.org/eep/eeps/eep-0048.html) format
-  * [Date] Add `Date.months_in_year/1` function
-  * [DynamicSupervisor] Use the name of the `DynamicSupervisor` as the ID whenever possible
-  * [Exception] Provide "did you mean" suggestions on KeyError
-  * [Exception] Provide more information on ArithmeticError on Erlang/OTP 21+
-  * [Function] Add `Function` module with `capture/3`, `info/1` and `info/2` functions
-  * [GenServer] Support the new `handle_continue/2` callback on Erlang/OTP 21+
-  * [IO.ANSI] Add cursor movement to `IO.ANSI`
-  * [Kernel] Support adding arbitrary documentation metadata by passing a keyword list to `@doc`, `@moduledoc` and `@typedoc`
-  * [Kernel] Introduce `__STACKTRACE__` to retrieve the current stacktrace inside `catch`/`rescue` (this will be a requirement for Erlang/OTP 21+)
-  * [Kernel] Raise on unsafe variables in order to allow us to better track unused variables
-  * [Kernel] Warn when using `length` to check if a list is not empty on guards
-  * [Kernel] Add hints on mismatched `do`/`end` and others pairs
-  * [Kernel] Warn when comparing structs using the `>`, `<`, `>=` and `<=` operators
-  * [Kernel] Warn on unsupported nested comparisons such as `x < y < z`
-  * [Kernel] Warn if redefining documentation across clauses of the same definition
-  * [Kernel] Warn on unnecessary quotes around atoms, keywords and calls
-  * [Macro] Add `Macro.special_form?/2` and `Macro.operator?/2` that returns `true` if the given name/arity is a special form or operator respectively
-  * [Macro.Env] Add `Macro.Env.vars/1` and `Macro.Env.has_var?/2` that gives access to environment data without accessing private fields
-  * [Regex] Include endianness in the regex version. This allows regexes to be recompiled when an archive is installed in a system with a different endianness
-  * [Registry] Add `Registry.count/1` and `Registry.count_match/4`
-  * [String] Update to Unicode 11
-  * [StringIO] Add `StringIO.open/3`
-  * [System] Use ISO 8601 in `System.build_info/0`
+  * [Application] Add `spec/1` and `spec/2` to retrieve application specification
+  * [Application] Add `get_application/1` to retrieve the application a given module belongs to
+  * [Base] Optimize encode and decode operations about 10 times
+  * [Enum] Use the faster and auto-seeding `:rand` instead of `:random` in `Enum.shuffle/1` and `Enum.random/1` and `Enum.take_random/2`
+  * [Enum] Add `Enum.with_index/2`
+  * [GenServer] Add `GenServer.stop/1` for shutting down servers reliably
+  * [IO] Add `color` related functions to `IO.ANSI`
+  * [Kernel] Support multiple aliases in `alias`, `import`, `require` and `use`. For example, `alias MyApp.{Foo, Bar, Baz}`
+  * [Kernel] Add `struct!/2`. Similar to `struct/2` but raises on invalid keys
+  * [Kernel] Warn if `@doc/@typedoc/@moduledoc` attributes are redefined
+  * [Kernel] Warn if non-variables are used in `defdelegate/2` (as they have no effect)
+  * [Kernel] Mark quoted expressions as generated, avoiding false positives on dialyzer
+  * [Kernel] Allow variables as map keys on creation `%{key => value}` and on matches `%{^key => value}`
+  * [Kernel] Allow the pin operator `^` in `fn` clauses and on the left side of `<-` in `for` comprehensions
+  * [Kernel] Introduce `with` as a special form that allows matching on right side parameters
+  * [Kernel] Warn when right hand side of `->` does not provide any expression
+  * [Kernel] Warn if the Elixir was compiled with a different endianness than the one currently available at runtime
+  * [Kernel] Warn if a variable is used after being defined exclusively in a nested context
+  * [Kernel] Warn if piping into an expression without parentheses
+  * [Macro] Add `Macro.traverse/4` that performs pre and post-walk at once
+  * [Macro] Add `Macro.camelize/1` and `Macro.underscore/1`
+  * [Process] Add `Process.get_keys/0`
+  * [Stream] Add `Stream.with_index/2`
+  * [String] Introduce `String.replace_{prefix,suffix,leading,trailing}/2`. The first two will replace only the first occurrence of the given match in string. The last two will replace all occurrences of the given match
+  * [String] Support `String.normalize/2` and `String.equivalent?/2` that perform NFD and NFC normalization
+  * [System] Add `System.time_offset`, `System.monotonic_time`, `System.system_time`, `System.convert_time_unit` and `System.unique_integer`
+  * [System] Allow `System.cmd/3` to remove variables by specifying nil values
+  * [Task] Add `Task.Supervisor.async_nolink/1/3` that spawns a supervised task without linking to the caller process
+  * [Task] Introduce `Task.yield_many/2`
+  * [Task] Raise an error when a task is queried from a non-owning process (instead of waiting forever)

 #### ExUnit

-  * [ExUnit.Assertion] Print the arguments in error reports when asserting on a function call. For example, if `assert is_list(arg)` fails, the argument will be shown in the report
-  * [ExUnit.Diff] Improve diffing of lists when one list is a subset of the other
-  * [ExUnit.DocTest] Show colored diffs on failed doctests
-  * [ExUnit.Formatter] Excluded tests, via the `--exclude` and `--only` flags, are now shown as "Excluded" in reports. Tests skipped via `@tag :skip` are now exclusively shown as "Skipped" and in yellow
+  * [ExUnit] Allow one test to raise multiple errors. The goal is to enable tools in the ecosystem to emit multiple failure reports from the same test
+  * [ExUnit] Support `@tag report: [:foo, :bar]` which will include the values for tags `:foo` and `:bar` whenever a test fails

 #### IEx

-  * [IEx.Helpers] Add `use_if_available/2`
-  * [IEx.Helpers] Allow `force: true` option in `recompile/1`
-  * [IEx.Helpers] Add `:allocators` pane to `runtime_info/1`
-  * [IEx.Helpers] Show documentation metadata in `h/1` helpers
+  * [IEx] Allow `IEX_WITH_WERL` to be set on Windows to always run on WERL mode
+  * [IEx] Display type docs for `t(Module.type)` and `t(Module.type/arity)`
+  * [IEx] Add `i/1` helper that prints information about any data type
+  * [IEx] Show source code snippet whenever there is a request to pry a given process

 #### Logger

-  * [Logger] Ensure nil metadata is always pruned
-  * [Logger] Only evaluate Logger macro arguments when the message will be logged
-  * [Logger] Add `:compile_time_purge_matching` to purge logger calls that match certain compile time metadata, such as module names and application names
-  * [Logger] Log to `:stderr` if a backend fails and there are no other backends
-  * [Logger] Allow translators to return custom metadata
-  * [Logger] Return `:crash_reason`, `:initial_call` and `:registered_name` as metadata in crash reports coming from Erlang/OTP
+  * [Logger] Add file to logger metadata

 #### Mix

-  * [mix archive.install] Add support for the Hex organization via `--organization`
-  * [mix archive.uninstall] Support `--force` flag
-  * [mix compile] Improve support for external build tools such as `rebar`
-  * [mix deps] Include `override: true` in rebar dependencies to make the behaviour closer to how rebar3 works (although diverged deps are still marked as diverged)
-  * [mix escript.install] Add support for the Hex organization via `--organization`
-  * [mix escript.uninstall] Support `--force` flag
-  * [mix help] Also list aliases
-  * [mix local] Use ipv6 with auto fallback to ipv4 when downloading data
-  * [mix profile] Allow all profiling tasks to run programatically
-  * [mix test] Add `--failed` option that only runs previously failed tests
-  * [mix test] Print coverage summary by default when the `--cover` flag is given
-  * [Mix.Project] Add `Mix.Project.clear_deps_cache/0`
-  * [Mix.Project] Add `Mix.Project.config_mtime/0` that caches the config mtime values to avoid filesystem access
+  * [Mix] Cache and always consolidate protocols
+  * [Mix] Add `warn_test_pattern` to `mix test` that will warn on potentially misconfigured test files
+  * [Mix] Introduce `MIX_QUIET` environment variable that configures the underlying Mix task to output only error messages
+  * [Mix] Introduce `MIX_DEBUG` environment variable that prints information about the task being run
+  * [Mix] Validate git options and warn on conflicting ref, branch or tags
+  * [Mix] New umbrella applications will now share configuration and build files
+  * [Mix] Add experimental support for Rebar 3
+  * [Mix] Do not warn when an optional dependency has a conflicting `:only` option with another dependency
+  * [Mix] Raise readable error message when parsertools is not available
+  * [Mix] Add `--build` flag to `mix deps.clean DEP` to only remove artifacts from `_build`

 ### 2. Bug fixes

-#### Elixir
+#### Kernel

-  * [IO.ANSI.Docs] Fix table column alignment when converting docs to ANSI escapes
-  * [Code] Ensure `string_to_quoted` returns error tuples instead of raising in certain constructs
-  * [Code.Formatter] Consistently format keyword lists in function calls with and without parens
-  * [Code.Formatter] Do not break after `->` when there are only comments and one-line clauses
-  * [File] Allow the `:trim_bom` option to be used with `:encoding`
-  * [Kernel] Raise on unsafe variables as some of the code emitted with unsafe variables would not correctly propagate variables or would disable tail call optimization semantics
-  * [Kernel] Do not crash on dynamic sizes in binary generators with collectable into in comprehensions
-  * [Kernel] Do not crash on literals with non-unary size in binary generators with collectable into in comprehensions
-  * [Task] Improve error reports and exit reasons for failed tasks on Erlang/OTP 20+
+  * [Access] Improve error messages when using Access on non-valid key-value structures
+  * [Kernel] Raise when conflicting `:only` and `:except` are given to import
+  * [Kernel] Change `__ENV__.file` if `@file` is set for the given function
+  * [Kernel] Make `Kernel.ParallelRequire` aware of `:warning_as_errors`
+  * [Kernel] Improve error message for invalid `do`/`do:`
+  * [Macro] Ensure `Macro.to_string/2` respects operator precedence when using the access operator
+  * [Path] Do not crash when expanding paths that go beyond the root, for example, `Path.expand("/../..")`
+  * [String] Ensure `UnicodeConversionError` does not contain invalid string in its error message

-#### ExUnit
+#### IEx

-  * [ExUnit.Case] Raise proper error if `@tag` and `@moduletag` are used before `use ExUnit.Case`
-  * [ExUnit.Case] Raise proper error if `@describetag` is used outside of `describe/2` blocks
-  * [ExUnit.DocTest] Emit proper assertion error on doctests with invalid UTF-8
+  * [IEx] Do not start apps on `recompile` helper if `--no-start` was given
+  * [IEx] Avoid copying of data when evaluating every expression in IEx

 #### Mix

-  * [mix archive.install] Fetch optional dependencies when installing an archive from Git/Hex
-  * [mix compile] Properly track config files in umbrella projects and recompile when any relevant umbrella configuration changes
-  * [mix deps] Ensure the same dependency from different SCMs are tagged as diverged when those SCMs are remote and non-remote
-  * [mix deps] Ensure we re-run dependency resolution when overriding a skipped dep in umbrella
-  * [mix deps.compile] Perform clean builds for dependencies on outdated locks to avoid old modules from affecting future compilation
-  * [mix escript.install] Fetch optional dependencies when installing an escript from Git/Hex
+  * [Mix] Always run non-recursive tasks at the umbrella root
+  * [Mix] Ensure rebar projects work on directory names that contain non-latin characters
+  * [Mix] Ignore directories inside `apps` in umbrellas that do not have a `mix.exs` file
+  * [Mix] Ensure Mix can be used with path dependencies where the app name is different than the path basename
+  * [Mix] Ensure dependencies won't crash when updating from a git repository to a hex repository and the git version did not respect SemVer
+  * [Mix] Do not run remote converger if dependencies have diverged
+  * [Mix] Ensure umbrella dependencies across all environments are loaded on parent deps.get/deps.update

-### 3. Soft-deprecations (no warnings emitted)
+#### ExUnit

-#### Elixir
+  * [ExUnit] Include file and line in all compilation errors for doctests

-  * [Code] Deprecate `Code.load_file/2` in favor of `Code.compile_file/2`
-  * [Code] Deprecate `Code.loaded_files/0` in favor of `Code.required_files/0`
-  * [Code] Deprecate `Code.unload_files/1` in favor of `Code.unrequire_files/1`
+### 3. Soft deprecations (no warnings emitted)

-#### Logger
+#### Kernel

-  * [Logger] `compile_time_purge_level` is deprecated in favor of `compile_time_purge_matching`
+  * [Dict] `Dict` and `HashDict` are soft deprecated in favor of `Map`
+  * [Keyword] `Keyword.size/1` is deprecated in favor of `length/1`
+  * [Map] `Map.size/1` is deprecated in favor of `map_size/1`
+  * [Set] `Set` and `HashSet` are soft deprecated in favor of `MapSet`

-### 4. Hard-deprecations
+#### Mix

-#### Elixir
+  * [Mix] `Mix.Utils.camelize/1` and `Mix.Utils.underscore/1` are soft deprecated in favor of `Macro.camelize/1` and `Macro.underscore/1`

-  * [Code] `Code.get_docs/2` is deprecated in favor of `Code.fetch_docs/1`
-  * [Enum] `Enum.chunk/2/3/4` is deprecated in favor of `Enum.chunk_every/2/3/4` - notice `chunk_every` does not discard incomplete chunks by default
-  * [GenServer] Warn if `super` is used in any of the GenServer callbacks
-  * [Kernel] `not left in right` is ambiguous and is deprecated in favor of `left not in right`
-  * [Kernel] Warn on confusing operator sequences, such as `1+++1` meaning `1 ++ +1` or `........` meaning `... .. ...`
-  * [OptionParser] Deprecate dynamic option parser mode that depended on atoms to be previously loaded and therefore behaved inconsistently
-  * [Stream] `Stream.chunk/2/3/4` is deprecated in favor of `Stream.chunk_every/2/3/4` - notice `chunk_every` does not discard incomplete chunks by default
+## v1.1

-## v1.6
-
-The CHANGELOG for v1.6 releases can be found [in the v1.6 branch](https://github.com/elixir-lang/elixir/blob/v1.6/CHANGELOG.md).
+The CHANGELOG for v1.1 releases can be found [in the v1.1 branch](https://github.com/elixir-lang/elixir/blob/v1.1/CHANGELOG.md).
@@ -1,56 +1,22 @@
-# Code of Conduct
+# Contributor Code of Conduct

-Contact: elixir-lang-conduct@googlegroups.com
+As contributors and maintainers of this project, and in the interest of fostering an open and welcoming community, we pledge to respect all people who contribute through reporting issues, posting feature requests, updating documentation, submitting pull requests or patches, and other activities.

-## Why have a Code of Conduct?
+We are committed to making participation in this project a harassment-free experience for everyone, regardless of level of experience, gender, gender identity and expression, sexual orientation, disability, personal appearance, body size, race, ethnicity, age, religion, or nationality.

-As contributors and maintainers of this project, we are committed to providing a friendly, safe and welcoming environment for all, regardless of age, disability, gender, nationality, race, religion, sexuality, or similar personal characteristic.
+Examples of unacceptable behavior by participants include:

-The goal of the Code of Conduct is to specify a baseline standard of behavior so that people with different social values and communication styles can talk about Elixir effectively, productively, and respectfully, even in face of disagreements. The Code of Conduct also provides a mechanism for resolving conflicts in the community when they arise.
+* The use of sexualized language or imagery
+* Personal attacks
+* Trolling or insulting/derogatory comments
+* Public or private harassment
+* Publishing other's private information, such as physical or electronic addresses, without explicit permission
+* Other unethical or unprofessional conduct.

-## Our Values
+The Elixir Core Team has the right and responsibility to remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct. By adopting this Code of Conduct, we commit ourselves to fairly and consistently applying these principles to every aspect of managing this project. Project maintainers who do not follow or enforce the Code of Conduct may be permanently removed from the project team.

-These are the values Elixir developers should aspire to:
+This code of conduct applies both within project spaces and in public spaces when an individual is representing the project or its community.

-  * Be friendly and welcoming
-  * Be patient
-    * Remember that people have varying communication styles and that not everyone is using their native language. (Meaning and tone can be lost in translation.)
-  * Be thoughtful
-    * Productive communication requires effort. Think about how your words will be interpreted.
-    * Remember that sometimes it is best to refrain entirely from commenting.
-  * Be respectful
-    * In particular, respect differences of opinion. It is important that we resolve disagreements and differing views constructively.
-  * Avoid destructive behavior
-    * Derailing: stay on topic; if you want to talk about something else, start a new conversation.
-    * Unconstructive criticism: don't merely decry the current state of affairs; offer (or at least solicit) suggestions as to how things may be improved.
-    * Snarking (pithy, unproductive, sniping comments).
+Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by sending an e-mail to elixir-lang-conduct@googlegroups.com.

-The following actions are explicitly forbidden:
-
-  * Insulting, demeaning, hateful, or threatening remarks.
-  * Discrimination based on age, disability, gender, nationality, race, religion, sexuality, or similar personal characteristic.
-  * Bullying or systematic harassment.
-  * Unwelcome sexual advances.
-  * Incitement to any of these.
-
-## Where does the Code of Conduct apply?
-
-If you participate in or contribute to the Elixir ecosystem in any way, you are encouraged to follow the Code of Conduct while doing so.
-
-Explicit enforcement of the Code of Conduct applies to the official mediums operated by the Elixir project:
-
-* The official GitHub projects and code reviews.
-* The official elixir-lang mailing lists.
-* The #elixir-lang IRC channel on Freenode.
-
-Other Elixir activities (such as conferences, meetups, and other unofficial forums) are encouraged to adopt this Code of Conduct. Such groups must provide their own contact information.
-
-Project maintainers may remove, edit, or reject comments, commits, code, wiki edits, issues, and other contributions that are not aligned to this Code of Conduct.
-
-Instances of abusive, harassing, or otherwise unacceptable behavior may be reported by emailing: elixir-lang-conduct@googlegroups.com. All complaints will be reviewed and investigated and will result in a response that is deemed necessary and appropriate to the circumstances. **All reports will be kept confidential**.
-
-**The goal of the Code of Conduct is to resolve conflicts in the most harmonious way possible**. We hope that in most cases issues may be resolved through polite discussion and mutual agreement. Bannings and other forceful measures are to be employed only as a last resort. **Do not** post about the issue publicly or try to rally sentiment against a particular individual or group.
-
-## Acknowledgements
-
-This document was based on the Code of Conduct from the Go project with parts derived from Django's Code of Conduct, Rust's Code of Conduct and the Contributor Covenant.
+This Code of Conduct is adapted from the [Contributor Covenant](http://contributor-covenant.org), version 1.2.0, available at [http://contributor-covenant.org/version/1/2/0/](http://contributor-covenant.org/version/1/2/0/)
@@ -0,0 +1,275 @@
+# Contributing to Elixir
+
+Please take a moment to review this document in order to make the contribution
+process easy and effective for everyone involved!
+
+Also make sure you read our [Code of Conduct](CODE_OF_CONDUCT.md) that
+outlines our commitment towards an open and welcoming environment.
+
+## Using the issue tracker
+
+Use the issues tracker for:
+
+* [bug reports](#bug-reports)
+* [submitting pull requests](#pull-requests)
+
+Please **do not** use the issue tracker for personal support requests nor feature requests. Support requests should be sent to:
+
+* [the elixir-talk mailing list](https://groups.google.com/group/elixir-lang-talk)
+* [Stack Overflow](http://stackoverflow.com/questions/ask?tags=elixir)
+* **[#elixir-lang](irc://chat.freenode.net/elixir-lang)** IRC channel on [chat.freenode.net](http://www.freenode.net/)
+
+Feature requests can be discussed on [the elixir-core mailing list](https://groups.google.com/group/elixir-lang-core).
+
+We do our best to keep the issue tracker tidy and organized, making it useful
+for everyone. For example, we classify open issues per application and perceived
+difficulty of the issue, making it easier for developers to
+[contribute to Elixir](#contributing).
+
+## Bug reports
+
+A bug is a _demonstrable problem_ that is caused by the code in the repository.
+Good bug reports are extremely helpful - thank you!
+
+Guidelines for bug reports:
+
+1. **Use the GitHub issue search** &mdash; [check if the issue has already been
+   reported](https://github.com/elixir-lang/elixir/search?type=Issues).
+
+2. **Check if the issue has been fixed** &mdash; try to reproduce it using the
+   `master` branch in the repository.
+
+3. **Isolate and report the problem** &mdash; ideally create a reduced test
+   case.
+
+Please try to be as detailed as possible in your report. Include information about
+your Operating System, your Erlang and Elixir versions. Please provide steps to
+reproduce the issue as well as the outcome you were expecting! All these details
+will help developers to fix any potential bugs.
+
+Example:
+
+> Short and descriptive example bug report title
+>
+> A summary of the issue and the environment in which it occurs. If suitable,
+> include the steps required to reproduce the bug.
+>
+> 1. This is the first step
+> 2. This is the second step
+> 3. Further steps, etc.
+>
+> `<url>` - a link to the reduced test case (e.g. a GitHub Gist)
+>
+> Any other information you want to share that is relevant to the issue being
+> reported. This might include the lines of code that you have identified as
+> causing the bug, and potential solutions (and your opinions on their
+> merits).
+
+## Feature requests
+
+Feature requests are welcome and should be discussed on [the elixir-core mailing list](https://groups.google.com/group/elixir-lang-core). But take a moment to find
+out whether your idea fits with the scope and aims of the project. It's up to *you*
+to make a strong case to convince the community of the merits of this feature.
+Please provide as much detail and context as possible.
+
+## Contributing
+
+We incentivize everyone to contribute to Elixir and help us tackle
+existing issues! To do so, there are a few things you need to know
+about the code. First, Elixir code is divided in applications inside
+the `lib` folder:
+
+* `elixir` - Contains Elixir's kernel and stdlib
+
+* `eex` - Template engine that allows you to embed Elixir
+
+* `ex_unit` - Simple test framework that ships with Elixir
+
+* `iex` - IEx, Elixir's interactive shell
+
+* `mix` - Elixir's build tool
+
+You can run all tests in the root directory with `make test` and you can
+also run tests for a specific framework `make test_#{NAME}`, for example,
+`make test_ex_unit`.
+
+In case you are changing a single file, you can compile and run tests only
+for that particular file for fast development cycles. For example, if you
+are changing the String module, you can compile it and run its tests as:
+
+```sh
+bin/elixirc lib/elixir/lib/string.ex -o lib/elixir/ebin
+bin/elixir lib/elixir/test/elixir/string_test.exs
+```
+
+After your changes are done, please remember to run the full suite with
+`make test`.
+
+From time to time, your tests may fail in an existing Elixir checkout and
+may require a clean start by running `make clean compile`. You can always
+check [the official build status on Travis-CI](https://travis-ci.org/elixir-lang/elixir).
+
+With tests running and passing, you are ready to contribute to Elixir and
+send your pull requests.
+
+## Contributing Documentation
+
+Code documentation (`@doc`, `@moduledoc`, `@typedoc`) has a special convention:
+the first paragraph is considered to be a short summary.
+
+For functions, macros and callbacks say what it will do. For example write
+something like:
+
+```elixir
+@doc """
+Returns only those elements for which `fun` is `true`.
+
+...
+"""
+def filter(collection, fun) ...
+```
+
+For modules, protocols and types say what it is. For example write
+something like:
+
+```elixir
+defmodule File.Stat do
+  @moduledoc """
+  Information about a file.
+
+  ...
+  """
+
+  defstruct [...]
+end
+```
+
+Keep in mind that the first paragraph might show up in a summary somewhere, long
+texts in the first paragraph create very ugly summaries. As a rule of thumb
+anything longer than 80 characters is too long.
+
+Try to keep unnecessary details out of the first paragraph, it's only there to
+give a user a quick idea of what the documented "thing" does/is. The rest of the
+documentation string can contain the details, for example when a value and when
+`nil` is returned.
+
+If possible include examples, preferably in a form that works with doctests. For
+example:
+
+```elixir
+@doc """
+Returns only those elements for which `fun` is `true`.
+
+## Examples
+
+    iex> Enum.filter([1, 2, 3], fn(x) -> rem(x, 2) == 0 end)
+    [2]
+
+"""
+def filter(collection, fun) ...
+```
+
+This makes it easy to test the examples so that they don't go stale and examples
+are often a great help in explaining what a function does.
+
+## Pull requests
+
+Good pull requests - patches, improvements, new features - are a fantastic
+help. They should remain focused in scope and avoid containing unrelated
+commits.
+
+**NOTE**: Do not send code style changes as pull requests like changing
+the indentation of some particular code snippet or how a function is called.
+Those will not be accepted as they pollute the repository history with non
+functional changes and are often based on personal preferences.
+
+**IMPORTANT**: By submitting a patch, you agree that your work will be
+licensed under the license used by the project.
+
+If you have any large pull request in mind (e.g. implementing features,
+refactoring code, etc), **please ask first** otherwise you risk spending
+a lot of time working on something that the project's developers might
+not want to merge into the project.
+
+Please adhere to the coding conventions in the project (indentation,
+accurate comments, etc.) and don't forget to add your own tests and
+documentation. When working with Git, we recommend the following process
+in order to craft an excellent pull request:
+
+1. [Fork](https://help.github.com/fork-a-repo/) the project, clone your fork,
+  and configure the remotes:
+
+  ```sh
+  # Clone your fork of the repo into the current directory
+  git clone https://github.com/<your-username>/elixir
+  # Navigate to the newly cloned directory
+  cd elixir
+  # Assign the original repo to a remote called "upstream"
+  git remote add upstream https://github.com/elixir-lang/elixir
+  ```
+
+2. If you cloned a while ago, get the latest changes from upstream:
+
+  ```sh
+  git checkout master
+  git pull upstream master
+  ```
+
+3. Create a new topic branch (off of `master`) to contain your feature, change,
+  or fix.
+
+  **IMPORTANT**: Making changes in `master` is discouraged. You should always
+  keep your local `master` in sync with upstream `master` and make your
+  changes in topic branches.
+
+  ```sh
+  git checkout -b <topic-branch-name>
+  ```
+
+4. Commit your changes in logical chunks. Keep your commit messages organized,
+  with a short description in the first line and more detailed information on
+  the following lines. Feel free to use Git's
+  [interactive rebase](https://help.github.com/articles/interactive-rebase)
+  feature to tidy up your commits before making them public.
+
+5. Make sure all the tests are still passing.
+
+  ```sh
+  make test
+  ```
+
+  This command will compile the code in your branch and use that
+  version of Elixir to run the tests. This is needed to ensure your changes can
+  pass all the tests.
+
+6. Push your topic branch up to your fork:
+
+  ```sh
+  git push origin <topic-branch-name>
+  ```
+
+7. [Open a Pull Request](https://help.github.com/articles/using-pull-requests/)
+  with a clear title and description.
+
+8. If you haven't updated your pull request for a while, you should consider
+  rebasing on master and resolving any conflicts.
+
+  **IMPORTANT**: _Never ever_ merge upstream `master` into your branches. You
+  should always `git rebase` on `master` to bring your changes up to date when
+  necessary.
+
+  ```sh
+  git checkout master
+  git pull upstream master
+  git checkout <your-topic-branch>
+  git rebase master
+  ```
+
+We have saved some excellent pull requests we have received in the past in case
+you are looking for some examples:
+
+* [Implement Enum.member? – Pull Request](https://github.com/elixir-lang/elixir/pull/992)
+* [Add String.valid? – Pull Request](https://github.com/elixir-lang/elixir/pull/1058)
+* [Implement capture_io for ExUnit – Pull Request](https://github.com/elixir-lang/elixir/pull/1059)
+
+Thank you for your contributions!
@@ -1,18 +0,0 @@
-### Precheck
-
-* Do not use the issues tracker for help or support (try Elixir Forum, Stack Overflow, IRC, etc.)
-* For proposing a new feature, please start a discussion on the Elixir Core mailing list
-* For bugs, do a quick search and make sure the bug has not yet been reported
-* Finally, be nice and have fun!
-
-### Environment
-
-* Elixir & Erlang/OTP versions (elixir --version): 
-* Operating system: 
-
-### Current behavior
-
-Include code samples, errors and stacktraces if appropriate.
-
-### Expected behavior
-
@@ -1,201 +1,13 @@
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
+Copyright 2012 Plataformatec

-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at

-   1. Definitions.
+      http://www.apache.org/licenses/LICENSE-2.0

-      "License" shall mean the terms and conditions for use, reproduction,
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-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
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-   6. Trademarks. This License does not grant permission to use the trade
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-      origin of the Work and reproducing the content of the NOTICE file.
-
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-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
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-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
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-      Work (including but not limited to damages for loss of goodwill,
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-      the Work or Derivative Works thereof, You may choose to offer,
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-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "{}"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright 2012 Plataformatec
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
@@ -1,32 +1,29 @@
+REBAR ?= "$(CURDIR)/rebar"
 PREFIX ?= /usr/local
-SHARE_PREFIX ?= $(PREFIX)/share
-CANONICAL := v1.7/
+DOCS := v1.2
+CANONICAL := stable
 ELIXIRC := bin/elixirc --verbose --ignore-module-conflict
 ERLC := erlc -I lib/elixir/include
 ERL := erl -I lib/elixir/include -noshell -pa lib/elixir/ebin
-GENERATE_APP := $(CURDIR)/lib/elixir/generate_app.escript
 VERSION := $(strip $(shell cat VERSION))
 Q := @
 LIBDIR := lib
-BINDIR := bin
 INSTALL = install
 INSTALL_DIR = $(INSTALL) -m755 -d
 INSTALL_DATA = $(INSTALL) -m644
 INSTALL_PROGRAM = $(INSTALL) -m755
-GIT_REVISION = $(strip $(shell git rev-parse HEAD 2> /dev/null ))
-GIT_TAG = $(strip $(shell head="$(call GIT_REVISION)"; git tag --points-at $$head 2> /dev/null | tail -1) )

-.PHONY: install compile erlang elixir unicode app build_plt clean_plt dialyze test clean clean_residual_files install_man clean_man docs Docs.zip Precompiled.zip zips
+.PHONY: install compile erlang elixir build_plt clean_plt dialyze test clean install_man clean_man docs Docs.zip Precompiled.zip publish_zips publish_docs publish_mix
 .NOTPARALLEL: compile

 #==> Functions

 define CHECK_ERLANG_RELEASE
-	erl -noshell -eval '{V,_} = string:to_integer(erlang:system_info(otp_release)), io:fwrite("~s", [is_integer(V) and (V >= 19)])' -s erlang halt | grep -q '^true'; \
-		if [ $$? != 0 ]; then \
-		  echo "At least Erlang/OTP 19.0 is required to build Elixir"; \
-		  exit 1; \
-		fi
+	$(Q) erl -noshell -eval 'io:fwrite("~s", [erlang:system_info(otp_release) >= "18"])' -s erlang halt | grep -q '^true'; \
+		if [ $$? != 0 ]; then                                                                                                \
+		   echo "At least Erlang 18.0 is required to build Elixir";                                                          \
+		   exit 1;                                                                                                           \
+		fi;
 endef

 define APP_TEMPLATE
@@ -51,49 +48,46 @@ endef

 #==> Compilation tasks

-APP := lib/elixir/ebin/elixir.app
-PARSER := lib/elixir/src/elixir_parser.erl
-KERNEL := lib/elixir/ebin/Elixir.Kernel.beam
-UNICODE := lib/elixir/ebin/Elixir.String.Unicode.beam
+KERNEL:=lib/elixir/ebin/Elixir.Kernel.beam
+UNICODE:=lib/elixir/ebin/Elixir.String.Unicode.beam

 default: compile

-compile: erlang $(APP) elixir
+compile: lib/elixir/src/elixir.app.src erlang elixir

-erlang: $(PARSER)
-	$(Q) if [ ! -f $(APP) ]; then $(call CHECK_ERLANG_RELEASE); fi
-	$(Q) cd lib/elixir && mkdir -p ebin && erl -make
+lib/elixir/src/elixir.app.src: src/elixir.app.src
+	$(Q) $(call CHECK_ERLANG_RELEASE)
+	$(Q) rm -rf lib/elixir/src/elixir.app.src
+	$(Q) echo "%% This file is automatically generated from <project_root>/src/elixir.app.src" \
+	                             >lib/elixir/src/elixir.app.src
+	$(Q) cat src/elixir.app.src >>lib/elixir/src/elixir.app.src

-$(PARSER): lib/elixir/src/elixir_parser.yrl
-	$(Q) erlc -o $@ +'{verbose,true}' +'{report,true}' $<
+erlang:
+	$(Q) cd lib/elixir && $(REBAR) compile

-# Since Mix depends on EEx and EEx depends on Mix,
-# we first compile EEx without the .app file,
-# then Mix and then compile EEx fully
+# Since Mix depends on EEx and EEx depends on
+# Mix, we first compile EEx without the .app
+# file, then mix and then compile EEx fully
 elixir: stdlib lib/eex/ebin/Elixir.EEx.beam mix ex_unit logger eex iex

 stdlib: $(KERNEL) VERSION
 $(KERNEL): lib/elixir/lib/*.ex lib/elixir/lib/*/*.ex lib/elixir/lib/*/*/*.ex
-	$(Q) if [ ! -f $(KERNEL) ]; then \
-		echo "==> bootstrap (compile)"; \
-		$(ERL) -s elixir_compiler bootstrap -s erlang halt; \
+	$(Q) if [ ! -f $(KERNEL) ]; then                    \
+		echo "==> bootstrap (compile)";                 \
+		$(ERL) -s elixir_compiler core -s erlang halt;  \
 	fi
 	@ echo "==> elixir (compile)";
 	$(Q) cd lib/elixir && ../../$(ELIXIRC) "lib/kernel.ex" -o ebin;
 	$(Q) cd lib/elixir && ../../$(ELIXIRC) "lib/**/*.ex" -o ebin;
 	$(Q) $(MAKE) unicode
-	$(Q) $(MAKE) app
-
-app: $(APP)
-$(APP): lib/elixir/src/elixir.app.src lib/elixir/ebin VERSION $(GENERATE_APP)
-	$(Q) $(GENERATE_APP) $< $@ $(VERSION)
+	$(Q) rm -rf lib/elixir/ebin/elixir.app
+	$(Q) cd lib/elixir && $(REBAR) compile

 unicode: $(UNICODE)
 $(UNICODE): lib/elixir/unicode/*
 	@ echo "==> unicode (compile)";
-	$(Q) $(ELIXIRC) lib/elixir/unicode/unicode.ex -o lib/elixir/ebin;
-	$(Q) $(ELIXIRC) lib/elixir/unicode/properties.ex -o lib/elixir/ebin;
-	$(Q) $(ELIXIRC) lib/elixir/unicode/tokenizer.ex -o lib/elixir/ebin;
+	@ echo "Embedding the Unicode database... (this may take a while)"
+	$(Q) cd lib/elixir && ../../$(ELIXIRC) unicode/unicode.ex -o ebin;

 $(eval $(call APP_TEMPLATE,ex_unit,ExUnit))
 $(eval $(call APP_TEMPLATE,logger,Logger))
@@ -104,51 +98,45 @@ $(eval $(call APP_TEMPLATE,iex,IEx))
 install: compile
 	@ echo "==> elixir (install)"
 	$(Q) for dir in lib/*; do \
-		rm -rf $(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/$$dir/ebin; \
+		rm -Rf $(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/$$dir/ebin; \
 		$(INSTALL_DIR) "$(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/$$dir/ebin"; \
 		$(INSTALL_DATA) $$dir/ebin/* "$(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/$$dir/ebin"; \
 	done
 	$(Q) $(INSTALL_DIR) "$(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/bin"
 	$(Q) $(INSTALL_PROGRAM) $(filter-out %.ps1, $(filter-out %.bat, $(wildcard bin/*))) "$(DESTDIR)$(PREFIX)/$(LIBDIR)/elixir/bin"
-	$(Q) $(INSTALL_DIR) "$(DESTDIR)$(PREFIX)/$(BINDIR)"
-	$(Q) for file in "$(DESTDIR)$(PREFIX)"/$(LIBDIR)/elixir/bin/*; do \
-		ln -sf "../$(LIBDIR)/elixir/bin/$${file##*/}" "$(DESTDIR)$(PREFIX)/$(BINDIR)/"; \
+	$(Q) $(INSTALL_DIR) "$(DESTDIR)$(PREFIX)/bin"
+	$(Q) for file in "$(DESTDIR)$(PREFIX)"/$(LIBDIR)/elixir/bin/* ; do \
+		ln -sf "../$(LIBDIR)/elixir/bin/$${file##*/}" "$(DESTDIR)$(PREFIX)/bin/" ; \
 	done
 	$(MAKE) install_man

 clean:
+	cd lib/elixir && $(REBAR) clean
 	rm -rf ebin
 	rm -rf lib/*/ebin
-	rm -rf $(PARSER)
-	$(Q) $(MAKE) clean_residual_files
+	rm -rf lib/elixir/test/ebin
+	rm -rf lib/*/tmp
+	rm -rf lib/mix/test/fixtures/git_repo
+	rm -rf lib/mix/test/fixtures/deps_on_git_repo
+	rm -rf lib/mix/test/fixtures/git_rebar
+	rm -rf lib/elixir/src/elixir.app.src
+	$(MAKE) clean_man

-clean_elixir:
+clean_exbeam:
 	$(Q) rm -f lib/*/ebin/Elixir.*.beam

-clean_residual_files:
-	rm -rf lib/*/_build/
-	rm -rf lib/*/tmp/
-	rm -rf lib/elixir/test/ebin/
-	rm -rf lib/mix/test/fixtures/deps_on_git_repo/
-	rm -rf lib/mix/test/fixtures/git_rebar/
-	rm -rf lib/mix/test/fixtures/git_repo/
-	rm -rf lib/mix/test/fixtures/git_sparse_repo/
-	rm -f erl_crash.dump
-	$(Q) $(MAKE) clean_man
-
-#==> Documentation tasks
+#==>  Create Documentation

 LOGO_PATH = $(shell test -f ../docs/logo.png && echo "--logo ../docs/logo.png")
-SOURCE_REF = $(shell tag="$(call GIT_TAG)" revision="$(call GIT_REVISION)"; echo "$${tag:-$$revision}\c")
-DOCS_FORMAT = html
-COMPILE_DOCS = bin/elixir ../ex_doc/bin/ex_doc "$(1)" "$(VERSION)" "lib/$(2)/ebin" -m "$(3)" -u "https://github.com/elixir-lang/elixir" --source-ref "$(call SOURCE_REF)" $(call LOGO_PATH) -o doc/$(2) -n https://hexdocs.pm/$(2)/$(CANONICAL) -p http://elixir-lang.org/docs.html -f "$(DOCS_FORMAT)" $(4)
+SOURCE_REF = $(shell head="$$(git rev-parse HEAD)" tag="$$(git tag --points-at $$head | tail -1)" ; echo "$${tag:-$$head}\c")
+COMPILE_DOCS = bin/elixir ../ex_doc/bin/ex_doc "$(1)" "$(VERSION)" "lib/$(2)/ebin" -m "$(3)" -u "https://github.com/elixir-lang/elixir" --source-ref "v$(VERSION)" $(call LOGO_PATH) -o doc/$(2) -a http://elixir-lang.org/docs/$(CANONICAL)/$(2)/ -p http://elixir-lang.org/docs.html $(4)

 docs: compile ../ex_doc/bin/ex_doc docs_elixir docs_eex docs_mix docs_iex docs_ex_unit docs_logger

 docs_elixir: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (elixir)"
 	$(Q) rm -rf doc/elixir
-	$(call COMPILE_DOCS,Elixir,elixir,Kernel,-c lib/elixir/docs.exs)
+	$(call COMPILE_DOCS,Elixir,elixir,Kernel,-e "lib/elixir/pages/Typespecs.md" -e "lib/elixir/pages/Writing Documentation.md")

 docs_eex: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (eex)"
@@ -179,45 +167,34 @@ docs_logger: compile ../ex_doc/bin/ex_doc
 	@ echo "ex_doc is not found in ../ex_doc as expected. See README for more information."
 	@ false

-#==> Zip tasks
+#==> Zips

 Docs.zip: docs
-	rm -f Docs-v$(VERSION).zip
+	rm -rf Docs-v$(VERSION).zip
 	zip -9 -r Docs-v$(VERSION).zip CHANGELOG.md doc NOTICE LICENSE README.md
 	@ echo "Docs file created $(CURDIR)/Docs-v$(VERSION).zip"

 Precompiled.zip: build_man compile
-	rm -f Precompiled-v$(VERSION).zip
-	zip -9 -r Precompiled-v$(VERSION).zip bin CHANGELOG.md lib/*/ebin lib/*/lib LICENSE man NOTICE README.md VERSION
+	rm -rf Precompiled-v$(VERSION).zip
+	zip -9 -r Precompiled-v$(VERSION).zip bin CHANGELOG.md lib/*/ebin LICENSE man NOTICE README.md VERSION
 	@ echo "Precompiled file created $(CURDIR)/Precompiled-v$(VERSION).zip"

-zips: Precompiled.zip Docs.zip
-	@ echo ""
-	@ echo "## Checksums"
-	@ echo ""
-	@ shasum -a 1 < Precompiled-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Precompiled.zip SHA1:"
-	@ shasum -a 512 < Precompiled-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Precompiled.zip SHA512:"
-	@ shasum -a 1 < Docs-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Docs.zip SHA1:"
-	@ shasum -a 512 < Docs-v$(VERSION).zip | sed -e "s/-//" | xargs echo "  * Docs.zip SHA512:"
-	@ echo ""
+#==> Publish

-#==> Test tasks
+publish_zips: Precompiled.zip Docs.zip

-test: test_formatted test_erlang test_elixir
+publish_docs: docs
+	rm -rf ../docs/$(DOCS)/*/
+	cp -R doc/* ../docs/$(DOCS)

-test_windows: test test_taskkill
+#==> Tests tasks

-test_taskkill:
-	taskkill //IM erl.exe //F //T //FI "MEMUSAGE gt 0"
-	taskkill //IM epmd.exe //F //T //FI "MEMUSAGE gt 0"
+test: test_erlang test_elixir

 TEST_ERL = lib/elixir/test/erlang
 TEST_EBIN = lib/elixir/test/ebin
 TEST_ERLS = $(addprefix $(TEST_EBIN)/, $(addsuffix .beam, $(basename $(notdir $(wildcard $(TEST_ERL)/*.erl)))))

-test_formatted: compile
-	bin/elixir bin/mix format --check-formatted
-
 test_erlang: compile $(TEST_ERLS)
 	@ echo "==> elixir (eunit)"
 	$(Q) $(ERL) -pa $(TEST_EBIN) -s test_helper test;
@@ -262,26 +239,24 @@ build_man: man/iex.1 man/elixir.1

 man/iex.1:
 	$(Q) cp man/iex.1.in man/iex.1
-	$(Q) sed -i.bak "/{COMMON}/r man/common" man/iex.1
+	$(Q) sed -i.bak "/{COMMON}/r common" man/iex.1
 	$(Q) sed -i.bak "/{COMMON}/d" man/iex.1
-	$(Q) rm -f man/iex.1.bak
+	$(Q) rm man/iex.1.bak

 man/elixir.1:
 	$(Q) cp man/elixir.1.in man/elixir.1
-	$(Q) sed -i.bak "/{COMMON}/r man/common" man/elixir.1
+	$(Q) sed -i.bak "/{COMMON}/r common" man/elixir.1
 	$(Q) sed -i.bak "/{COMMON}/d" man/elixir.1
-	$(Q) rm -f man/elixir.1.bak
+	$(Q) rm man/elixir.1.bak

 clean_man:
 	rm -f man/elixir.1
-	rm -f man/elixir.1.bak
 	rm -f man/iex.1
-	rm -f man/iex.1.bak

 install_man: build_man
-	$(Q) mkdir -p $(DESTDIR)$(SHARE_PREFIX)/man/man1
-	$(Q) $(INSTALL_DATA) man/elixir.1  $(DESTDIR)$(SHARE_PREFIX)/man/man1
-	$(Q) $(INSTALL_DATA) man/elixirc.1 $(DESTDIR)$(SHARE_PREFIX)/man/man1
-	$(Q) $(INSTALL_DATA) man/iex.1     $(DESTDIR)$(SHARE_PREFIX)/man/man1
-	$(Q) $(INSTALL_DATA) man/mix.1     $(DESTDIR)$(SHARE_PREFIX)/man/man1
+	$(Q) mkdir -p $(DESTDIR)$(PREFIX)/share/man/man1
+	$(Q) $(INSTALL_DATA) man/elixir.1  $(DESTDIR)$(PREFIX)/share/man/man1
+	$(Q) $(INSTALL_DATA) man/elixirc.1 $(DESTDIR)$(PREFIX)/share/man/man1
+	$(Q) $(INSTALL_DATA) man/iex.1     $(DESTDIR)$(PREFIX)/share/man/man1
+	$(Q) $(INSTALL_DATA) man/mix.1     $(DESTDIR)$(PREFIX)/share/man/man1
 	$(MAKE) clean_man
@@ -1,16 +1,15 @@
 ![Elixir](https://github.com/elixir-lang/elixir-lang.github.com/raw/master/images/logo/logo.png)
 =========
-[![Travis build](https://secure.travis-ci.org/elixir-lang/elixir.svg?branch=master
+[![Build Status](https://secure.travis-ci.org/elixir-lang/elixir.svg?branch=master 
 "Build Status")](https://travis-ci.org/elixir-lang/elixir)

-Elixir is a dynamic, functional language designed for building scalable and maintainable applications.
-
 For more about Elixir, installation and documentation,
 [check Elixir's website](http://elixir-lang.org/).

-## Compiling from source
+## Usage

-To run Elixir from source, clone this repository to your machine, compile and test it:
+If you want to contribute to Elixir or run it from source, clone this
+repository to your machine, compile and test it:

 ```sh
 git clone https://github.com/elixir-lang/elixir.git
@@ -26,133 +25,26 @@ If Elixir fails to build (specifically when pulling in a new version via
 `git`), be sure to remove any previous build artifacts by running
 `make clean`, then `make test`.

-If tests pass, you are ready to move on to the [Getting Started guide][1]
-or to try Interactive Elixir by running `bin/iex` in your terminal.
+If tests pass, you are ready to move on to the
+[Getting Started guide][1] or to try Interactive Elixir by running:
+`bin/iex` in your terminal.

-However, if tests fail, it is likely you have an outdated Erlang/OTP version
-(Elixir requires Erlang/OTP 19.0 or later). You can check your Erlang/OTP version
-by calling `erl` in the command line. You will see some information as follows:
+However, if tests fail, it is likely you have an outdated Erlang version
+(Elixir requires Erlang 18.0 or later).
+You can check your Erlang version by calling `erl` in the command line.
+You will see some information as follows:

-    Erlang/OTP 19 [erts-8.0] [smp:2:2] [async-threads:10] [kernel-poll:false]
+`Erlang/OTP 18 [erts-7.0] [source] [smp:2:2] [async-threads:10] [hipe]
+[kernel-poll:false]`

-If you have properly set up your dependencies and tests still fail,
-you may want to open up a bug report, as explained next.
-
-## Bug reports
-
-For reporting bugs, [visit our issues tracker][2] and follow the steps
-for reporting a new issue. Please disclose security vulnerabilities
-privately at elixir-security@googlegroups.com.
-
-## Proposing new features
-
-For proposing new features, please start a discussion in the
-[Elixir Core mailing list][3]. Keep in mind that it is your responsibility
-to argue and explain why a feature is useful and how it will impact the
-codebase and the community.
-
-Once a proposal is accepted, it will be added to [the issues tracker][2].
-The issues tracker focuses on *actionable items* and it holds a list of
-upcoming enhancements and pending bugs. All entries in the tracker are
-tagged for clarity and to ease collaboration.
-
-Features and bug fixes that have already been merged and will be included
-in the next release are marked as "closed" in the issues tracker and are
-added to the [CHANGELOG](CHANGELOG.md).
-
-Finally, remember all interactions in our official spaces follow our
-[Code of Conduct][7].
-
-## Contributing
-
-We welcome everyone to contribute to Elixir. To do so, there are a few
-things you need to know about the code. First, Elixir code is divided
-in applications inside the `lib` folder:
-
-* `elixir` - Contains Elixir's kernel and stdlib
-
-* `eex` - Template engine that allows you to embed Elixir
-
-* `ex_unit` - Simple test framework that ships with Elixir
-
-* `iex` - IEx, Elixir's interactive shell
-
-* `logger` - The built-in logger
-
-* `mix` - Elixir's build tool
-
-You can run all tests in the root directory with `make test` and you can
-also run tests for a specific framework `make test_#{NAME}`, for example,
-`make test_ex_unit`. If you just changed something in the Elixir's standard
-library, you can run only that portion through `make test_stdlib`.
-
-If you are changing just one file, you can choose to compile and run tests only
-for that particular file for fast development cycles. For example, if you
-are changing the String module, you can compile it and run its tests as:
-
-```sh
-bin/elixirc lib/elixir/lib/string.ex -o lib/elixir/ebin
-bin/elixir lib/elixir/test/elixir/string_test.exs
-```
-
-To recompile (including Erlang modules):
-
-```sh
-make compile
-```
-
-After your changes are done, please remember to run the full suite with
-`make test` and then `mix format` to guarantee all files are properly
-formatted.
-
-If your contribution fails during the bootstrapping of the language,
-you can rebuild the language from scratch with:
-
-```sh
-make clean_elixir compile
-```
-
-Similarly, if you can't get Elixir to compile or the tests to pass after
-updating an existing checkout, run `make clean compile`. You can check
-[the official build status on Travis-CI](https://travis-ci.org/elixir-lang/elixir).
-More tasks can be found by reading the [Makefile](./Makefile).
-
-With tests running and passing, you are ready to contribute to Elixir and
-[send a pull request](https://help.github.com/articles/using-pull-requests/).
-We have saved some excellent pull requests we have received in the past in
-case you are looking for some examples:
-
-* [Implement Enum.member? – Pull Request](https://github.com/elixir-lang/elixir/pull/992)
-* [Add String.valid? – Pull Request](https://github.com/elixir-lang/elixir/pull/1058)
-* [Implement capture_io for ExUnit – Pull Request](https://github.com/elixir-lang/elixir/pull/1059)
-
-### Reviewing changes
-
-Once a pull request is sent, the Elixir team will review your changes.
-We outline our process below to clarify the roles of everyone involved.
-
-All pull requests must be approved by two committers before being merged into
-the repository. If any changes are necessary, the team will leave appropriate
-comments requesting changes to the code. Unfortunately we cannot guarantee a
-pull request will be merged, even when modifications are requested, as the Elixir
-team will re-evaluate the contribution as it changes.
-
-Committers may also push style changes directly to your branch. If you would
-rather manage all changes yourself, you can disable "Allow edits from maintainers"
-feature when submitting your pull request.
-
-The Elixir team may optionally assign someone to review a pull request.
-If someone is assigned, they must explicitly approve the code before
-another team member can merge it.
-
-When the review finishes, your pull request will be squashed and merged
-into the repository. If you have carefully organized your commits and
-believe they should be merged without squashing, leave a comment.
+If you have the correct version and tests still fail, feel free to
+[open an issue][2].

 ## Building documentation

-Building the documentation requires [ExDoc](https://github.com/elixir-lang/ex_doc)
-to be installed and built alongside Elixir:
+Building the documentation requires
+[ExDoc](https://github.com/elixir-lang/ex_doc) to be installed and built
+alongside Elixir.

 ```sh
 # After cloning and compiling Elixir, in its parent directory:
@@ -161,26 +53,31 @@ cd ex_doc && ../elixir/bin/mix do deps.get, compile
 cd ../elixir && make docs
 ```

-This will produce documentation sets for `elixir`, `mix`, etc. under
-the `doc` directory. If you are planning to contribute documentation,
-[please check our best practices for writing documentation](https://hexdocs.pm/elixir/writing-documentation.html).
+This will produce documentation sets for `elixir`, `mix`, etc., under the `doc` directory.

-## Development links
+## Contributing

-  * [Elixir Getting Started guide][1]
-  * [Elixir Documentation][6]
-  * [Elixir Core Mailing list (development)][3]
-  * [Issues tracker][2]
-  * [Code of Conduct][7]
-  * **[#elixir-lang][4]** on [Freenode][5] IRC
+We appreciate any contribution to Elixir.
+Check our [CODE_OF_CONDUCT.md](CODE_OF_CONDUCT.md) and
+[CONTRIBUTING.md](CONTRIBUTING.md) guides for more information.
+We usually keep a list of features and bugs [in the issue tracker][2].

-  [1]: https://elixir-lang.org/getting-started/introduction.html
+## Important links
+
+* [Elixir Website][1]
+* [Elixir Documentation][7]
+* **[#elixir-lang][5]** on [Freenode][6] IRC
+* [Issue tracker][2]
+* [elixir-talk Mailing list (questions)][3]
+* [elixir-core Mailing list (development)][4]
+
+  [1]: http://elixir-lang.org
  [2]: https://github.com/elixir-lang/elixir/issues
-  [3]: https://groups.google.com/group/elixir-lang-core
-  [4]: https://webchat.freenode.net/?channels=#elixir-lang
-  [5]: http://www.freenode.net
-  [6]: http://elixir-lang.org/docs.html
-  [7]: CODE_OF_CONDUCT.md
+  [3]: https://groups.google.com/group/elixir-lang-talk
+  [4]: https://groups.google.com/group/elixir-lang-core
+  [5]: https://webchat.freenode.net/?channels=#elixir-lang
+  [6]: http://www.freenode.net
+  [7]: http://elixir-lang.org/docs.html

 ## License

@@ -1,41 +1,41 @@
 # Release process

-## Shipping a new version
+## All releases
+
+This document simply outlines the release process:

 1. Ensure you are running on the oldest supported Erlang version

-2. Update version in /VERSION
+2. Remove all `-dev` extension from versions (see below for all files)

-3. Ensure /CHANGELOG.md is updated, versioned and add the current date
+3. Ensure CHANGELOG is updated and add current date

-4. Update "Compatibility and Deprecations" if a new OTP version is supported
+4. Commit changes above with title "Release vVERSION" and generate new tag

-5. Commit changes above with title "Release vVERSION" and generate a new tag
+5. Run `make clean test` to ensure all tests pass from scratch and the CI is green

-6. Run `make clean test` to ensure all tests pass from scratch and the CI is green
+6. Recompile an existing project (for example, Ecto) to ensure manifests can be upgraded

-7. Recompile an existing project (for example, Ecto) to ensure manifests can be upgraded
+7. Push branch and the new tag

-8. Push branch and the new tag
+8. Publish new docs with `make publish_docs`, copy docs to `docs/stable` if appropriate, and push to GitHub Pages

-9. Publish new zips with `make zips`, upload `Precompiled.zip` and `Docs.zip` to GitHub Releases, and include SHAs+CHANGELOG
+9. Publish new zips with `make publish_zips`, upload `Precompiled.zip` and `Docs.zip` to GitHub Releases

-10. Add the release to `elixir.csv` and `_data/elixir-versions.yml` files in `elixir-lang/elixir-lang.github.com`
+10. Add the release to `elixir.csv` file in `elixir-lang/elixir-lang.github.com`

-## Creating a new vMAJOR.MINOR branch
+11. Build and push standalone Mix with `make publish_mix` (requires AWS credentials)

-### In the new branch
+## New vMAJOR.MINOR releases

-1. Set `CANONICAL=` in /Makefile
+12. Create a new branch "vMAJOR.MINOR"

-2. Update **all** tables in "Compatibility and Deprecations"
+13. Move docs generation to `docs/vMAJOR.MINOR` in Makefile and copy them from `docs/stable` (change index.html accordingly)

-3. Commit "Prepare vMAJOR.MINOR for release"
+14. In master, bump versions, start new CHANGELOG, add `-dev` back and commit "Start vVERSION+1"

-### Back in master
+## Places where version is mentioned

-1. Bump /VERSION file
-
-2. Start new /CHANGELOG.md
-
-3. Commit "Start vMAJOR.MINOR+1"
+* VERSION (make sure there is no newline in this file)
+* CHANGELOG.md
+* src/elixir.app.src (not lib/elixir/src/elixir.app.src)
@@ -1 +1 @@
-1.7.4
+1.2.6
@@ -2,26 +2,22 @@
 if [ $# -eq 0 ] || [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
  echo "Usage: `basename $0` [options] [.exs file] [data]

-  -e COMMAND                  Evaluates the given command (*)
-  -r FILE                     Requires the given files/patterns (*)
-  -S SCRIPT                   Finds and executes the given script in PATH
-  -pr FILE                    Requires the given files/patterns in parallel (*)
-  -pa PATH                    Prepends the given path to Erlang code path (*)
-  -pz PATH                    Appends the given path to Erlang code path (*)
-
-  --app APP                   Starts the given app and its dependencies (*)
-  --cookie COOKIE             Sets a cookie for this distributed node
-  --detached                  Starts the Erlang VM detached from console
-  --erl SWITCHES              Switches to be passed down to Erlang (*)
-  --help, -h                  Prints this message and exits
-  --hidden                    Makes a hidden node
-  --logger-otp-reports BOOL   Enables or disables OTP reporting
-  --logger-sasl-reports BOOL  Enables or disables SASL reporting
-  --name NAME                 Makes and assigns a name to the distributed node
-  --no-halt                   Does not halt the Erlang VM after execution
-  --sname NAME                Makes and assigns a short name to the distributed node
-  --version, -v               Prints Elixir version and exits
-  --werl                      Uses Erlang's Windows shell GUI (Windows only)
+  -v                Prints version and exits
+  -e \"command\"      Evaluates the given command (*)
+  -r \"file\"         Requires the given files/patterns (*)
+  -S \"script\"       Finds and executes the given script
+  -pr \"file\"        Requires the given files/patterns in parallel (*)
+  -pa \"path\"        Prepends the given path to Erlang code path (*)
+  -pz \"path\"        Appends the given path to Erlang code path (*)
+  --app \"app\"       Start the given app and its dependencies (*)
+  --erl \"switches\"  Switches to be passed down to Erlang (*)
+  --name \"name\"     Makes and assigns a name to the distributed node
+  --sname \"name\"    Makes and assigns a short name to the distributed node
+  --cookie \"cookie\" Sets a cookie for this distributed node
+  --hidden          Makes a hidden node
+  --detached        Starts the Erlang VM detached from console
+  --werl            Uses Erlang's Windows shell GUI (Windows only)
+  --no-halt         Does not halt the Erlang VM after execution

 ** Options marked with (*) can be given more than once
 ** Options given after the .exs file or -- are passed down to the executed code
@@ -72,20 +68,6 @@ while [ $I -le $# ]; do
        eval "VAL=\${$I}"
        ERL="$ERL `echo $PEEK | cut -c 2-` "$VAL""
        ;;
-    --logger-otp-reports)
-        I=$(expr $I + 1)
-        eval "VAL=\${$I}"
-        if [ "$VAL" = 'true' ] || [ "$VAL" = 'false' ]; then
-            ERL="$ERL -logger handle_otp_reports "$VAL""
-        fi
-        ;;
-    --logger-sasl-reports)
-        I=$(expr $I + 1)
-        eval "VAL=\${$I}"
-        if [ "$VAL" = 'true' ] || [ "$VAL" = 'false' ]; then
-            ERL="$ERL -logger handle_sasl_reports "$VAL""
-        fi
-        ;;
    --erl)
        I=$(expr $I + 1)
        eval "VAL=\${$I}"
@@ -117,7 +99,11 @@ if [ "$OS" = "Windows_NT" ] && [ $USE_WERL ]; then
 fi

 if [ -z "$ERL_PATH" ]; then
-  ERL_PATH="$ERL_EXEC"
+  if [ -f "$SCRIPT_PATH/../releases/RELEASES" ] && [ -f "$SCRIPT_PATH/erl" ]; then
+    ERL_PATH="$SCRIPT_PATH"/"$ERL_EXEC"
+  else
+    ERL_PATH="$ERL_EXEC"
+  fi
 fi

 exec "$ERL_PATH" -pa "$SCRIPT_PATH"/../lib/*/ebin $ELIXIR_ERL_OPTIONS $ERL -extra "$@"
@@ -1,39 +1,34 @@
-@if defined ELIXIR_CLI_ECHO (@echo on) else (@echo off)
+@if defined ELIXIR_CLI_ECHO (@echo on) else  (@echo off)
 setlocal
-if    ""%1""==""""       goto documentation
-if /I ""%1""==""--help"" goto documentation
-if /I ""%1""==""-h""     goto documentation
-if /I ""%1""==""/h""     goto documentation
-if    ""%1""==""/?""     goto documentation
+if ""%1""==""""       goto :documentation
+if ""%1""==""--help"" goto :documentation
+if ""%1""==""-h""     goto :documentation
+if ""%1""==""/h""     goto :documentation
 goto parseopts

 :documentation
 echo Usage: %~nx0 [options] [.exs file] [data]
 echo.
-echo   -e COMMAND                  Evaluates the given command (*)
-echo   -r FILE                     Requires the given files/patterns (*)
-echo   -S SCRIPT                   Finds and executes the given script in PATH
-echo   -pr FILE                    Requires the given files/patterns in parallel (*)
-echo   -pa PATH                    Prepends the given path to Erlang code path (*)
-echo   -pz PATH                    Appends the given path to Erlang code path (*)
-echo.
-echo   --app APP                   Starts the given app and its dependencies (*)
-echo   --cookie COOKIE             Sets a cookie for this distributed node
-echo   --detached                  Starts the Erlang VM detached from console
-echo   --erl SWITCHES              Switches to be passed down to Erlang (*)
-echo   --help, -h                  Prints this message and exits
-echo   --hidden                    Makes a hidden node
-echo   --logger-otp-reports BOOL   Enables or disables OTP reporting
-echo   --logger-sasl-reports BOOL  Enables or disables SASL reporting
-echo   --name NAME                 Makes and assigns a name to the distributed node
-echo   --no-halt                   Does not halt the Erlang VM after execution
-echo   --sname NAME                Makes and assigns a short name to the distributed node
-echo   --version, -v               Prints Elixir version and exits
-echo   --werl                      Uses Erlang's Windows shell GUI
+echo   -v                Prints version and exits
+echo   -e command        Evaluates the given command (*)
+echo   -r file           Requires the given files/patterns (*)
+echo   -S script         Finds and executes the given script
+echo   -pr file          Requires the given files/patterns in parallel (*)
+echo   -pa path          Prepends the given path to Erlang code path (*)
+echo   -pz path          Appends the given path to Erlang code path (*)
+echo   --app app         Start the given app and its dependencies (*)
+echo   --erl switches    Switches to be passed down to erlang (*)
+echo   --name name       Makes and assigns a name to the distributed node
+echo   --sname name      Makes and assigns a short name to the distributed node
+echo   --cookie cookie   Sets a cookie for this distributed node
+echo   --hidden          Makes a hidden node
+echo   --detached        Starts the Erlang VM detached from console
+echo   --werl            Uses Erlang's Windows shell GUI
+echo   --no-halt         Does not halt the Erlang VM after execution
 echo.
 echo ** Options marked with (*) can be given more than once
 echo ** Options given after the .exs file or -- are passed down to the executed code
-echo ** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS or --erl
+echo ** Options can be passed to the erlang runtime using ELIXIR_ERL_OPTIONS or --erl
 goto end

 :parseopts
@@ -62,52 +57,49 @@ set par="%1"
 shift
 if "%par%"=="" (
  rem if no parameters defined
-  goto expand_erl_libs
+  goto :expand_erl_libs
 )
 if "%par%"=="""" (
  rem if no parameters defined - special case for parameter that is already quoted
-  goto expand_erl_libs
+  goto :expand_erl_libs
 )
 rem ******* EXECUTION OPTIONS **********************
-if "%par%"==""--werl"" (set useWerl=1)
-if "%par%"==""+iex"" (set runMode="iex")
-rem ******* ELIXIR PARAMETERS **********************
+IF "%par%"==""--werl"" (Set useWerl=1)
+IF "%par%"==""+iex"" (Set runMode="iex")
+rem ******* elixir parameters **********************
 rem Note: we don't have to do anything with options that don't take an argument
-if """"=="%par:-e=%"      (shift)
-if """"=="%par:-r=%"      (shift)
-if """"=="%par:-pr=%"     (shift)
-if """"=="%par:-pa=%"     (shift)
-if """"=="%par:-pz=%"     (shift)
-if """"=="%par:--app=%"   (shift)
-if """"=="%par:--remsh=%" (shift)
+IF """"=="%par:-e=%"      (shift) 
+IF """"=="%par:-r=%"      (shift) 
+IF """"=="%par:-pr=%"     (shift) 
+IF """"=="%par:-pa=%"     (shift) 
+IF """"=="%par:-pz=%"     (shift) 
+IF """"=="%par:--app=%"   (shift) 
+IF """"=="%par:--remsh=%" (shift) 
 rem ******* ERLANG PARAMETERS **********************
-if """"=="%par:--detached=%"            (set parsErlang=%parsErlang% -detached)
-if """"=="%par:--hidden=%"              (set parsErlang=%parsErlang% -hidden)
-if """"=="%par:--cookie=%"              (set parsErlang=%parsErlang% -setcookie %1 && shift)
-if """"=="%par:--sname=%"               (set parsErlang=%parsErlang% -sname %1 && shift)
-if """"=="%par:--name=%"                (set parsErlang=%parsErlang% -name %1 && shift)
-if """"=="%par:--logger-otp-reports=%"  (set parsErlang=%parsErlang% -logger handle_otp_reports %1 && shift)
-if """"=="%par:--logger-sasl-reports=%" (set parsErlang=%parsErlang% -logger handle_sasl_reports %1 && shift)
-if """"=="%par:--erl=%"                 (set "beforeExtra=%beforeExtra% %~1" && shift)
+IF """"=="%par:--detached=%" (Set parsErlang=%parsErlang% -detached) 
+IF """"=="%par:--hidden=%"   (Set parsErlang=%parsErlang% -hidden)
+IF """"=="%par:--cookie=%"   (Set parsErlang=%parsErlang% -setcookie %1 && shift)
+IF """"=="%par:--sname=%"    (Set parsErlang=%parsErlang% -sname %1 && shift) 
+IF """"=="%par:--name=%"     (Set parsErlang=%parsErlang% -name %1 && shift) 
+IF """"=="%par:--erl=%"      (Set beforeExtra=%beforeExtra% %~1 && shift) 
 goto:startloop

 rem ******* assume all pre-params are parsed ********************
 :expand_erl_libs
 rem ******* expand all ebin paths as Windows does not support the ..\*\ebin wildcard ********************
-setlocal enabledelayedexpansion
+SETLOCAL enabledelayedexpansion
 set ext_libs=
 for  /d %%d in ("%originPath%..\lib\*.") do (
  set ext_libs=!ext_libs! -pa "%%~fd\ebin"
 )
-setlocal disabledelayedexpansion
-
+SETLOCAL disabledelayedexpansion
 :run
-if not %runMode% == "iex" (
+IF NOT %runMode% == "iex" (
  set beforeExtra=-noshell -s elixir start_cli %beforeExtra%
 )
-if %useWerl% equ 1 (
+IF %useWerl% EQU 1 (
  start werl.exe %ext_libs% %ELIXIR_ERL_OPTIONS% %parsErlang% %beforeExtra% -extra %*
-) else (
+) ELSE (
  erl.exe %ext_libs% %ELIXIR_ERL_OPTIONS% %parsErlang% %beforeExtra% -extra %*
 )
 :end
@@ -2,19 +2,16 @@
 if [ $# -eq 0 ] || [ "$1" = "--help" ] || [ "$1" = "-h" ]; then
  echo "Usage: `basename $0` [elixir switches] [compiler switches] [.ex files]

-  -o                        The directory to output compiled files
-
-  --help, -h                Prints this message and exits
-  --ignore-module-conflict  Does not emit warnings if a module was previously defined
-  --no-debug-info           Does not attach debug info to compiled modules
-  --no-docs                 Does not attach documentation to compiled modules
-  --verbose                 Prints compilation status
-  --version, -v             Prints Elixir version and exits
-  --warnings-as-errors      Treats warnings as errors and return non-zero exit code
+  -o               The directory to output compiled files
+  --no-docs        Do not attach documentation to compiled modules
+  --no-debug-info  Do not attach debug info to compiled modules
+  --ignore-module-conflict
+  --warnings-as-errors Treat warnings as errors and return non-zero exit code
+  --verbose        Print informational messages.

 ** Options given after -- are passed down to the executed code
-** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS
-** Options can be passed to the Erlang compiler using ERL_COMPILER_OPTIONS" >&2
+** Options can be passed to the erlang runtime using ELIXIR_ERL_OPTIONS
+** Options can be passed to the erlang compiler using ERL_COMPILER_OPTIONS" >&2
  exit 1
 fi

@@ -1,12 +1,10 @@
-@if defined ELIXIR_CLI_ECHO (@echo on) else (@echo off)
-setlocal
+@if defined ELIXIR_CLI_ECHO (@echo on) else  (@echo off)
 set argc=0
 for %%A in (%*) do (
-  if /I "%%A"=="--help" goto documentation
-  if /I "%%A"=="-h"     goto documentation
-  if /I "%%A"=="/h"     goto documentation
-  if    "%%A"=="/?"     goto documentation
-  set /A argc+=1
+    if "%%A"=="--help" goto documentation
+    if "%%A"=="-h"     goto documentation
+    if "%%A"=="/h"     goto documentation
+    set /A argc+=1
 )
 if %argc%==0 goto documentation
 goto run
@@ -14,23 +12,15 @@ goto run
 :documentation
 echo Usage: %~nx0 [elixir switches] [compiler switches] [.ex files]
 echo.
-echo   -o                        The directory to output compiled files
-echo.
-echo   --help, -h                Prints this message and exits
-echo   --ignore-module-conflict  Does not emit warnings if a module was previously defined
-echo   --no-debug-info           Does not attach debug info to compiled modules
-echo   --no-docs                 Does not attach documentation to compiled modules
-echo   --verbose                 Prints compilation status
-echo   --version, -v             Prints Elixir version and exits
-echo   --warnings-as-errors      Treats warnings as errors and returns non-zero exit code
+echo  -o               The directory to output compiled files
+echo  --no-docs        Do not attach documentation to compiled modules
+echo  --no-debug-info  Do not attach debug info to compiled modules
+echo  --ignore-module-conflict
+echo  --warnings-as-errors Treat warnings as errors and return non-zero exit code
+echo  --verbose        Print informational messages.
 echo.
 echo ** Options given after -- are passed down to the executed code
 echo ** Options can be passed to the Erlang runtime using ELIXIR_ERL_OPTIONS
-echo ** Options can be passed to the Erlang compiler using ERL_COMPILER_OPTIONS
-goto end
-
+echo ** Options can be passed to the Erlang compiler using ERL_COMPILER_OPTIONS >&2
 :run
 call "%~dp0\elixir.bat" +elixirc %*
-
-:end
-endlocal
@@ -2,30 +2,24 @@
 if [ $# -gt 0 ] && ([ "$1" = "--help" ] || [ "$1" = "-h" ]); then
  echo "Usage: `basename $0` [options] [.exs file] [data]

-  -e COMMAND                  Evaluates the given command (*)
-  -r FILE                     Requires the given files/patterns (*)
-  -S SCRIPT                   Finds and executes the given script in PATH
-  -pr FILE                    Requires the given files/patterns in parallel (*)
-  -pa PATH                    Prepends the given path to Erlang code path (*)
-  -pz PATH                    Appends the given path to Erlang code path (*)
-
-  --app APP                   Starts the given app and its dependencies (*)
-  --cookie COOKIE             Sets a cookie for this distributed node
-  --detached                  Starts the Erlang VM detached from console
-  --erl SWITCHES              Switches to be passed down to Erlang (*)
-  --help, -h                  Prints this message and exits
-  --hidden                    Makes a hidden node
-  --logger-otp-reports BOOL   Enables or disables OTP reporting
-  --logger-sasl-reports BOOL  Enables or disables SASL reporting
-  --name NAME                 Makes and assigns a name to the distributed node
-  --no-halt                   Does not halt the Erlang VM after execution
-  --sname NAME                Makes and assigns a short name to the distributed node
-  --version, -v               Prints IEx version and exits
-  --werl                      Uses Erlang's Windows shell GUI (Windows only)
-
-  --dot-iex PATH              Overrides default .iex.exs file and uses path instead;
-                              path can be empty, then no file will be loaded
-  --remsh NAME                Connects to a node using a remote shell
+  -v                Prints version
+  -e \"command\"      Evaluates the given command (*)
+  -r \"file\"         Requires the given files/patterns (*)
+  -S \"script\"       Finds and executes the given script
+  -pr \"file\"        Requires the given files/patterns in parallel (*)
+  -pa \"path\"        Prepends the given path to Erlang code path (*)
+  -pz \"path\"        Appends the given path to Erlang code path (*)
+  --app \"app\"       Start the given app and its dependencies (*)
+  --erl \"switches\"  Switches to be passed down to Erlang (*)
+  --name \"name\"     Makes and assigns a name to the distributed node
+  --sname \"name\"    Makes and assigns a short name to the distributed node
+  --cookie \"cookie\" Sets a cookie for this distributed node
+  --hidden          Makes a hidden node
+  --werl            Uses Erlang's Windows shell GUI (Windows only)
+  --detached        Starts the Erlang VM detached from console
+  --remsh \"name\"    Connects to a node using a remote shell
+  --dot-iex \"path\"  Overrides default .iex.exs file and uses path instead;
+                    path can be empty, then no file will be loaded

 ** Options marked with (*) can be given more than once
 ** Options given after the .exs file or -- are passed down to the executed code
@@ -45,4 +39,4 @@ readlink_f () {

 SELF=$(readlink_f "$0")
 SCRIPT_PATH=$(dirname "$SELF")
-exec "$SCRIPT_PATH"/elixir --no-halt --erl "-noshell -user Elixir.IEx.CLI" +iex "$@"
+exec "$SCRIPT_PATH"/elixir --no-halt --erl "-user Elixir.IEx.CLI" +iex "$@"
@@ -1,46 +1,4 @@
@if defined ELIXIR_CLI_ECHO (@echo on) else  (@echo off)
-setlocal
-if /I ""%1""==""--help"" goto documentation
-if /I ""%1""==""-h""     goto documentation
-if /I ""%1""==""/h""     goto documentation
-if    ""%1""==""/?""     goto documentation
-goto run
-
-:documentation
-echo Usage: %~nx0 [options] [.exs file] [data]
-echo.
-echo   -e COMMAND                  Evaluates the given command (*)
-echo   -r FILE                     Requires the given files/patterns (*)
-echo   -S SCRIPT                   Finds and executes the given script in PATH
-echo   -pr FILE                    Requires the given files/patterns in parallel (*)
-echo   -pa PATH                    Prepends the given path to Erlang code path (*)
-echo   -pz PATH                    Appends the given path to Erlang code path (*)
-echo.
-echo   --app APP                   Starts the given app and its dependencies (*)
-echo   --cookie COOKIE             Sets a cookie for this distributed node
-echo   --detached                  Starts the Erlang VM detached from console
-echo   --erl SWITCHES              Switches to be passed down to Erlang (*)
-echo   --help, -h                  Prints this message and exits
-echo   --hidden                    Makes a hidden node
-echo   --logger-otp-reports BOOL   Enables or disables OTP reporting
-echo   --logger-sasl-reports BOOL  Enables or disables SASL reporting
-echo   --name NAME                 Makes and assigns a name to the distributed node
-echo   --no-halt                   Does not halt the Erlang VM after execution
-echo   --sname NAME                Makes and assigns a short name to the distributed node
-echo   --version, -v               Prints IEx version and exits
-echo   --werl                      Uses Erlang's Windows shell GUI (Windows only)
-echo.
-echo   --dot-iex PATH              Overrides default .iex.exs file and uses path instead;
-echo                               path can be empty, then no file will be loaded
-echo   --remsh NAME                Connects to a node using a remote shell
-echo.
-echo ** Options marked with (*) can be given more than once
-echo ** Options given after the .exs file or -- are passed down to the executed code
-echo ** Options can be passed to the Erlang VM using ELIXIR_ERL_OPTIONS or --erl
-goto end
-
-:run
@if defined IEX_WITH_WERL (@set __ELIXIR_IEX_FLAGS=--werl) else (set __ELIXIR_IEX_FLAGS=)
-call "%~dp0\elixir.bat" --no-halt --erl "-noshell -user Elixir.IEx.CLI" +iex %__ELIXIR_IEX_FLAGS% %*
-:end
-endlocal
+call "%~dp0\elixir.bat" +iex --erl "-user Elixir.IEx.CLI" --no-halt %__ELIXIR_IEX_FLAGS% %*
+@set __ELIXIR_IEX_FLAGS=
@@ -1,2 +1,2 @@
-@if defined ELIXIR_CLI_ECHO (@echo on) else (@echo off)
-call "%~dp0\elixir.bat" "%~dp0\mix" %*
+@if defined ELIXIR_CLI_ECHO (@echo on) else  (@echo off)
+call "%~dp0\elixir.bat" "%~dp0\mix" %*
@@ -1,7 +1,6 @@
 defmodule EEx.SyntaxError do
  defexception [:message, :file, :line]

-  @impl true
  def message(exception) do
    "#{exception.file}:#{exception.line}: #{exception.message}"
  end
@@ -12,7 +11,7 @@ defmodule EEx do
  EEx stands for Embedded Elixir. It allows you to embed
  Elixir code inside a string in a robust way.

-      iex> EEx.eval_string("foo <%= bar %>", bar: "baz")
+      iex> EEx.eval_string "foo <%= bar %>", [bar: "baz"]
      "foo baz"

  ## API
@@ -36,14 +35,13 @@ defmodule EEx do

  ## Options

-  All functions in this module accept EEx-related options.
+  All functions in this module accepts EEx-related options.
  They are:

    * `:line` - the line to be used as the template start. Defaults to 1.
    * `:file` - the file to be used in the template. Defaults to the given
      file the template is read from or to "nofile" when compiling from a string.
    * `:engine` - the EEx engine to be used for compilation.
-    * `:trim` - trims whitespace left/right of quotation tags

  ## Engine

@@ -66,7 +64,7 @@ defmodule EEx do
  **must** use the equals sign (`=`). Since everything in
  Elixir is an expression, there are no exceptions for this rule.
  For example, while some template languages would special-case
-  `if/2` clauses, they are treated the same in EEx and
+  `if` clauses, they are treated the same in EEx and
  also require `=` in order to have their result printed:

      <%= if true do %>
@@ -84,14 +82,14 @@ defmodule EEx do
  An example is the `@` macro which allows easy data access
  in a template:

-      iex> EEx.eval_string("<%= @foo %>", assigns: [foo: 1])
+      iex> EEx.eval_string "<%= @foo %>", assigns: [foo: 1]
      "1"

  In other words, `<%= @foo %>` translates to:

      <%= {:ok, v} = Access.fetch(assigns, :foo); v %>

-  The `assigns` extension is useful when the number of variables
+  The assigns extension is useful when the number of variables
  required by the template is not specified at compilation time.
  """

@@ -112,14 +110,14 @@ defmodule EEx do

  """
  defmacro function_from_string(kind, name, source, args \\ [], options \\ []) do
-    quote bind_quoted: binding() do
-      info = Keyword.merge([file: __ENV__.file, line: __ENV__.line], options)
-      args = Enum.map(args, fn arg -> {arg, [line: info[:line]], nil} end)
+    quote bind_quoted: binding do
+      info = Keyword.merge [file: __ENV__.file, line: __ENV__.line], options
+      args = Enum.map args, fn arg -> {arg, [line: info[:line]], nil} end
      compiled = EEx.compile_string(source, info)

      case kind do
-        :def -> def unquote(name)(unquote_splicing(args)), do: unquote(compiled)
-        :defp -> defp unquote(name)(unquote_splicing(args)), do: unquote(compiled)
+        :def  -> def(unquote(name)(unquote_splicing(args)), do: unquote(compiled))
+        :defp -> defp(unquote(name)(unquote_splicing(args)), do: unquote(compiled))
      end
    end
  end
@@ -149,16 +147,16 @@ defmodule EEx do

  """
  defmacro function_from_file(kind, name, file, args \\ [], options \\ []) do
-    quote bind_quoted: binding() do
-      info = Keyword.merge(options, file: file, line: 1)
-      args = Enum.map(args, fn arg -> {arg, [line: 1], nil} end)
+    quote bind_quoted: binding do
+      info = Keyword.merge options, [file: file, line: 1]
+      args = Enum.map args, fn arg -> {arg, [line: 1], nil} end
      compiled = EEx.compile_file(file, info)

      @external_resource file
      @file file
      case kind do
-        :def -> def unquote(name)(unquote_splicing(args)), do: unquote(compiled)
-        :defp -> defp unquote(name)(unquote_splicing(args)), do: unquote(compiled)
+        :def  -> def(unquote(name)(unquote_splicing(args)), do: unquote(compiled))
+        :defp -> defp(unquote(name)(unquote_splicing(args)), do: unquote(compiled))
      end
    end
  end
@@ -167,8 +165,7 @@ defmodule EEx do
  Gets a string `source` and generate a quoted expression
  that can be evaluated by Elixir or compiled to a function.
  """
-  @spec compile_string(String.t(), keyword) :: Macro.t() | no_return
-  def compile_string(source, options \\ []) when is_binary(source) and is_list(options) do
+  def compile_string(source, options \\ []) do
    EEx.Compiler.compile(source, options)
  end

@@ -176,9 +173,8 @@ defmodule EEx do
  Gets a `filename` and generate a quoted expression
  that can be evaluated by Elixir or compiled to a function.
  """
-  @spec compile_file(String.t(), keyword) :: Macro.t() | no_return
-  def compile_file(filename, options \\ []) when is_binary(filename) and is_list(options) do
-    options = Keyword.merge(options, file: filename, line: 1)
+  def compile_file(filename, options \\ []) do
+    options = Keyword.merge options, [file: filename, line: 1]
    compile_string(File.read!(filename), options)
  end

@@ -187,13 +183,11 @@ defmodule EEx do

  ## Examples

-      iex> EEx.eval_string("foo <%= bar %>", bar: "baz")
+      iex> EEx.eval_string "foo <%= bar %>", [bar: "baz"]
      "foo baz"

  """
-  @spec eval_string(String.t(), keyword, keyword) :: any
-  def eval_string(source, bindings \\ [], options \\ [])
-      when is_binary(source) and is_list(bindings) and is_list(options) do
+  def eval_string(source, bindings \\ [], options \\ []) do
    compiled = compile_string(source, options)
    do_eval(compiled, bindings, options)
  end
@@ -210,10 +204,8 @@ defmodule EEx do
      EEx.eval_file "sample.eex", [bar: "baz"] #=> "foo baz"

  """
-  @spec eval_file(String.t(), keyword, keyword) :: any
-  def eval_file(filename, bindings \\ [], options \\ [])
-      when is_binary(filename) and is_list(bindings) and is_list(options) do
-    options = Keyword.put(options, :file, filename)
+  def eval_file(filename, bindings \\ [], options \\ []) do
+    options  = Keyword.put options, :file, filename
    compiled = compile_file(filename, options)
    do_eval(compiled, bindings, options)
  end
@@ -9,111 +9,55 @@ defmodule EEx.Compiler do
  and the engine together by handling the tokens and invoking
  the engine every time a full expression or text is received.
  """
-  @spec compile(String.t(), keyword) :: Macro.t() | no_return
-  def compile(source, opts) when is_binary(source) and is_list(opts) do
-    file = opts[:file] || "nofile"
-    line = opts[:line] || 1
-    trim = opts[:trim] || false
-
+  def compile(source, opts) do
+    file   = opts[:file] || "nofile"
+    line   = opts[:line] || 1
+    trim   = opts[:trim] || false
    case EEx.Tokenizer.tokenize(source, line, trim: trim) do
      {:ok, tokens} ->
-        state = %{
-          engine: opts[:engine] || @default_engine,
-          file: file,
-          line: line,
-          quoted: [],
-          start_line: nil
-        }
-
-        init = state.engine.init(opts)
-        generate_buffer(tokens, init, [], state)
-
+        state = %{engine: opts[:engine] || @default_engine,
+                  file: file, line: line, quoted: [], start_line: nil}
+        generate_buffer(tokens, "", [], state)
      {:error, line, message} ->
        raise EEx.SyntaxError, line: line, file: file, message: message
    end
  end

-  # Generates the buffers by handling each expression from the tokenizer.
-  # It returns Macro.t/0 or it raises.
+  # Generates the buffers by handling each expression from the tokenizer

-  defp generate_buffer([{:text, chars} | rest], buffer, scope, state) do
+  defp generate_buffer([{:text, chars}|t], buffer, scope, state) do
    buffer = state.engine.handle_text(buffer, IO.chardata_to_string(chars))
-    generate_buffer(rest, buffer, scope, state)
+    generate_buffer(t, buffer, scope, state)
  end

-  defp generate_buffer([{:expr, line, mark, chars} | rest], buffer, scope, state) do
-    expr = Code.string_to_quoted!(chars, line: line, file: state.file)
+  defp generate_buffer([{:expr, line, mark, chars}|t], buffer, scope, state) do
+    expr = Code.string_to_quoted!(chars, [line: line, file: state.file])
    buffer = state.engine.handle_expr(buffer, IO.chardata_to_string(mark), expr)
-    generate_buffer(rest, buffer, scope, state)
+    generate_buffer(t, buffer, scope, state)
  end

-  defp generate_buffer([{:start_expr, start_line, mark, chars} | rest], buffer, scope, state) do
-    {contents, line, rest} = look_ahead_text(rest, start_line, chars)
-
-    {contents, rest} =
-      generate_buffer(rest, state.engine.handle_begin(buffer), [contents | scope], %{
-        state
-        | quoted: [],
-          line: line,
-          start_line: start_line
-      })
-
+  defp generate_buffer([{:start_expr, start_line, mark, chars}|t], buffer, scope, state) do
+    {contents, line, t} = look_ahead_text(t, start_line, chars)
+    {contents, t} = generate_buffer(t, "", [contents|scope],
+                                    %{state | quoted: [], line: line, start_line: start_line})
    buffer = state.engine.handle_expr(buffer, IO.chardata_to_string(mark), contents)
-    generate_buffer(rest, buffer, scope, state)
+    generate_buffer(t, buffer, scope, state)
  end

-  defp generate_buffer([{:middle_expr, line, '', chars} | rest], buffer, [current | scope], state) do
+  defp generate_buffer([{:middle_expr, line, _, chars}|t], buffer, [current|scope], state) do
    {wrapped, state} = wrap_expr(current, line, buffer, chars, state)
-    state = %{state | line: line}
-    generate_buffer(rest, state.engine.handle_begin(buffer), [wrapped | scope], state)
+    generate_buffer(t, "", [wrapped|scope], %{state | line: line})
  end

-  defp generate_buffer(
-         [{:middle_expr, line, modifier, chars} | t],
-         buffer,
-         [_ | _] = scope,
-         state
-       ) do
-    message =
-      "unexpected beginning of EEx tag \"<%#{modifier}\" on \"<%#{modifier}#{chars}%>\", " <>
-        "please remove \"#{modifier}\" accordingly"
-
-    :elixir_errors.warn(line, state.file, message)
-    generate_buffer([{:middle_expr, line, '', chars} | t], buffer, scope, state)
-    # TODO: Make this an error on Elixir v2.0 since it accidentally worked previously.
-    # raise EEx.SyntaxError, message: message, file: state.file, line: line
-  end
-
-  defp generate_buffer([{:middle_expr, line, _, chars} | _], _buffer, [], state) do
-    raise EEx.SyntaxError,
-      message: "unexpected middle of expression <%#{chars}%>",
-      file: state.file,
-      line: line
-  end
-
-  defp generate_buffer([{:end_expr, line, '', chars} | rest], buffer, [current | _], state) do
+  defp generate_buffer([{:end_expr, line, _, chars}|t], buffer, [current|_], state) do
    {wrapped, state} = wrap_expr(current, line, buffer, chars, state)
-    tuples = Code.string_to_quoted!(wrapped, line: state.start_line, file: state.file)
+    tuples = Code.string_to_quoted!(wrapped, [line: state.start_line, file: state.file])
    buffer = insert_quoted(tuples, state.quoted)
-    {buffer, rest}
+    {buffer, t}
  end

-  defp generate_buffer([{:end_expr, line, modifier, chars} | t], buffer, [_ | _] = scope, state) do
-    message =
-      "unexpected beginning of EEx tag \"<%#{modifier}\" on end of " <>
-        "expression \"<%#{modifier}#{chars}%>\", please remove \"#{modifier}\" accordingly"
-
-    :elixir_errors.warn(line, state.file, message)
-    generate_buffer([{:end_expr, line, '', chars} | t], buffer, scope, state)
-    # TODO: Make this an error on Elixir v2.0 since it accidentally worked previously.
-    # raise EEx.SyntaxError, message: message, file: state.file, line: line
-  end
-
-  defp generate_buffer([{:end_expr, line, _, chars} | _], _buffer, [], state) do
-    raise EEx.SyntaxError,
-      message: "unexpected end of expression <%#{chars}%>",
-      file: state.file,
-      line: line
+  defp generate_buffer([{:end_expr, line, _, chars}|_], _buffer, [], state) do
+    raise EEx.SyntaxError, message: "unexpected token #{inspect chars}", file: state.file, line: line
  end

  defp generate_buffer([], buffer, [], state) do
@@ -121,10 +65,8 @@ defmodule EEx.Compiler do
  end

  defp generate_buffer([], _buffer, _scope, state) do
-    raise EEx.SyntaxError,
-      message: "unexpected end of string, expected a closing '<% end %>'",
-      file: state.file,
-      line: state.line
+    raise EEx.SyntaxError, message: "unexpected end of string, expected a closing '<% end %>'",
+                           file: state.file, line: state.line
  end

  # Creates a placeholder and wrap it inside the expression block
@@ -132,33 +74,23 @@ defmodule EEx.Compiler do
  defp wrap_expr(current, line, buffer, chars, state) do
    new_lines = List.duplicate(?\n, line - state.line)
    key = length(state.quoted)
-    placeholder = '__EEX__(' ++ Integer.to_charlist(key) ++ ');'
-    count = current ++ placeholder ++ new_lines ++ chars
-    new_state = %{state | quoted: [{key, state.engine.handle_end(buffer)} | state.quoted]}
-
-    {count, new_state}
+    placeholder = '__EEX__(' ++ Integer.to_char_list(key) ++ ');'
+    {current ++ placeholder ++ new_lines ++ chars,
+     %{state | quoted: [{key, buffer}|state.quoted]}}
  end

  # Look text ahead on expressions

-  defp look_ahead_text(
-         [{:text, text}, {:middle_expr, line, _, chars} | rest] = tokens,
-         start,
-         contents
-       ) do
+  defp look_ahead_text([{:text, text}, {:middle_expr, line, _, chars}|t]=list, start, contents) do
    if only_spaces?(text) do
-      {contents ++ text ++ chars, line, rest}
+      {contents ++ text ++ chars, line, t}
    else
-      {contents, start, tokens}
+      {contents, start, list}
    end
  end

-  defp look_ahead_text([{:middle_expr, line, _, chars} | rest], _start, contents) do
-    {contents ++ chars, line, rest}
-  end
-
-  defp look_ahead_text(tokens, start, contents) do
-    {contents, start, tokens}
+  defp look_ahead_text(t, start, contents) do
+    {contents, start, t}
  end

  defp only_spaces?(chars) do
@@ -168,7 +100,7 @@ defmodule EEx.Compiler do
  # Changes placeholder to real expression

  defp insert_quoted({:__EEX__, _, [key]}, quoted) do
-    {^key, value} = List.keyfind(quoted, key, 0)
+    {^key, value} = List.keyfind quoted, key, 0
    value
  end

@@ -181,7 +113,7 @@ defmodule EEx.Compiler do
  end

  defp insert_quoted(list, quoted) when is_list(list) do
-    Enum.map(list, &insert_quoted(&1, quoted))
+    Enum.map list, &insert_quoted(&1, quoted)
  end

  defp insert_quoted(other, _quoted) do
@@ -2,43 +2,21 @@ defmodule EEx.Engine do
  @moduledoc ~S"""
  Basic EEx engine that ships with Elixir.

-  An engine needs to implement six functions:
+  An engine needs to implement three functions:

-    * `init(opts)` - called at the beginning of every text
-      and it must return the initial state.
+    * `handle_body(quoted)` - receives the final built quoted
+      expression, should do final post-processing and return a
+      quoted expression.

-    * `handle_body(state)` - receives the state of the document
-      and it must return a quoted expression.
-
-    * `handle_text(state, text)` - it receives the state,
+    * `handle_text(buffer, text)` - it receives the buffer,
      the text and must return a new quoted expression.

-    * `handle_expr(state, marker, expr)` - it receives the state,
-      the marker, the expr and must return a new state.
-
-    * `handle_begin(state)` - called every time there a new state
-      is needed with an empty buffer. Typically called for do/end
-      blocks, case expressions, anonymous functions, etc
-
-    * `handle_end(state)` - opposite of `handle_begin(state)` and
-      it must return quoted expression
+    * `handle_expr(buffer, marker, expr)` - it receives the buffer,
+      the marker, the expr and must return a new quoted expression.

      The marker is what follows exactly after `<%`. For example,
      `<% foo %>` has an empty marker, but `<%= foo %>` has `"="`
-      as marker. The allowed markers so far are: 
-
-        * `""`
-        * `"="`
-        * `"/"`
-        * `"|"`
-
-      Markers `"/"` and `"|"` are only for use in custom EEx engines
-      and are not implemented by default. Using them without the
-      implementation raises `EEx.SyntaxError`.
-
-      If your engine does not implement all markers, please ensure that
-      `handle_expr/3` falls back to `EEx.Engine.handle_expr/3` 
-      to raise the proper error message.
+      as marker. The allowed markers so far are: `""` and `"="`.

      Read `handle_expr/3` below for more information about the markers
      implemented by default by this engine.
@@ -47,34 +25,17 @@ defmodule EEx.Engine do
  default implementations for the functions above.
  """

-  @type state :: term
-
-  @callback init(opts :: keyword) :: state
-  @callback handle_body(state) :: Macro.t()
-  @callback handle_text(state, text :: String.t()) :: state
-  @callback handle_expr(state, marker :: String.t(), expr :: Macro.t()) :: state
-  @callback handle_begin(state) :: state
-  @callback handle_end(state) :: Macro.t()
+  @callback handle_body(Macro.t) :: Macro.t
+  @callback handle_text(Macro.t, String.t) :: Macro.t
+  @callback handle_expr(Macro.t, String.t, Macro.t) :: Macro.t

  @doc false
  defmacro __using__(_) do
    quote do
      @behaviour EEx.Engine

-      def init(opts) do
-        EEx.Engine.init(opts)
-      end
-
-      def handle_body(quoted) do
-        EEx.Engine.handle_body(quoted)
-      end
-
-      def handle_begin(quoted) do
-        EEx.Engine.handle_begin(quoted)
-      end
-
-      def handle_end(quoted) do
-        EEx.Engine.handle_end(quoted)
+      def handle_body(body) do
+        EEx.Engine.handle_body(body)
      end

      def handle_text(buffer, text) do
@@ -85,7 +46,7 @@ defmodule EEx.Engine do
        EEx.Engine.handle_expr(buffer, marker, expr)
      end

-      defoverridable EEx.Engine
+      defoverridable [handle_body: 1, handle_expr: 3, handle_text: 2]
    end
  end

@@ -104,58 +65,30 @@ defmodule EEx.Engine do
      end

  """
-  @spec handle_assign(Macro.t()) :: Macro.t()
  def handle_assign({:@, meta, [{name, _, atom}]}) when is_atom(name) and is_atom(atom) do
    line = meta[:line] || 0
-    quote(line: line, do: EEx.Engine.fetch_assign!(var!(assigns), unquote(name)))
+    quote line: line, do: EEx.Engine.fetch_assign!(var!(assigns), unquote(name))
  end
-
  def handle_assign(arg) do
    arg
  end

  @doc false
-  # TODO: Raise on 2.0
-  @spec fetch_assign!(Access.t(), Access.key()) :: term | nil
+  # TODO: raise on 1.3 or 1.4
  def fetch_assign!(assigns, key) do
    case Access.fetch(assigns, key) do
      {:ok, val} ->
        val
-
      :error ->
        keys = Enum.map(assigns, &elem(&1, 0))
-
-        IO.warn(
-          "assign @#{key} not available in EEx template. " <>
-            "Please ensure all assigns are given as options. " <>
-            "Available assigns: #{inspect(keys)}"
-        )
-
+        IO.write :stderr, "warning: assign @#{key} not available in eex template. " <>
+                          "Please ensure all assigns are given as options. " <>
+                          "Available assigns: #{inspect keys}\n" <>
+                          Exception.format_stacktrace
        nil
    end
  end

-  @doc """
-  Returns an empty string as initial buffer.
-  """
-  def init(_opts) do
-    ""
-  end
-
-  @doc """
-  Returns an empty string as the new buffer.
-  """
-  def handle_begin(_previous) do
-    ""
-  end
-
-  @doc """
-  End of the new buffer.
-  """
-  def handle_end(quoted) do
-    quoted
-  end
-
  @doc """
  The default implementation simply returns the given expression.
  """
@@ -167,7 +100,7 @@ defmodule EEx.Engine do
  The default implementation simply concatenates text to the buffer.
  """
  def handle_text(buffer, text) do
-    quote(do: unquote(buffer) <> unquote(text))
+    quote do: unquote(buffer) <> unquote(text)
  end

  @doc """
@@ -175,11 +108,10 @@ defmodule EEx.Engine do

      <% Elixir expression - inline with output %>
      <%= Elixir expression - replace with result %>
-      <%/ Elixir expression - raise EEx.SyntaxError, to be implemented by custom engines %>
-      <%| Elixir expression - raise EEx.SyntaxError, to be implemented by custom engines %>

  All other markers are not implemented by this engine.
  """
+  @spec handle_expr(Macro.t, String.t, Macro.t) :: Macro.t
  def handle_expr(buffer, "=", expr) do
    quote do
      tmp1 = unquote(buffer)
@@ -194,9 +126,4 @@ defmodule EEx.Engine do
      tmp2
    end
  end
-
-  def handle_expr(_buffer, marker, _expr) when marker in ["/", "|"] do
-    raise EEx.SyntaxError,
-          "unsupported EEx syntax <%#{marker} %> (the syntax is valid but not supported by the current EEx engine)"
-  end
 end
@@ -1,51 +1,39 @@
 defmodule EEx.Tokenizer do
  @moduledoc false

-  @type content :: IO.chardata()
-  @type line :: non_neg_integer
-  @type marker :: '=' | '/' | '|' | ''
-  @type token ::
-          {:text, content}
-          | {:expr | :start_expr | :middle_expr | :end_expr, line, marker, content}
-
  @doc """
-  Tokenizes the given charlist or binary.
+  Tokenizes the given char list or binary.

  It returns {:ok, list} with the following tokens:

-    * `{:text, content}`
-    * `{:expr, line, marker, content}`
-    * `{:start_expr, line, marker, content}`
-    * `{:middle_expr, line, marker, content}`
-    * `{:end_expr, line, marker, content}`
+    * `{:text, contents}`
+    * `{:expr, line, marker, contents}`
+    * `{:start_expr, line, marker, contents}`
+    * `{:middle_expr, line, marker, contents}`
+    * `{:end_expr, line, marker, contents}`

  Or `{:error, line, error}` in case of errors.
  """
-  @spec tokenize(binary | charlist, line, keyword) :: {:ok, [token]} | {:error, line, String.t()}
  def tokenize(bin, line, opts \\ [])

-  def tokenize(bin, line, opts)
-      when is_binary(bin) and is_integer(line) and line >= 0 and is_list(opts) do
-    tokenize(String.to_charlist(bin), line, opts)
+  def tokenize(bin, line, opts) when is_binary(bin) do
+    tokenize(String.to_char_list(bin), line, opts)
  end

-  def tokenize(list, line, opts)
-      when is_list(list) and is_integer(line) and line >= 0 and is_list(opts) do
+  def tokenize(list, line, opts) do
    tokenize(list, line, opts, [], [])
  end

  defp tokenize('<%%' ++ t, line, opts, buffer, acc) do
-    tokenize(t, line, opts, [?%, ?< | buffer], acc)
+   tokenize t, line, opts, [?%, ?<|buffer], acc
  end

  defp tokenize('<%#' ++ t, line, opts, buffer, acc) do
    case expr(t, line, []) do
-      {:error, _, _} = error ->
-        error
-
+      {:error, _, _} = error -> error
      {:ok, _, new_line, rest} ->
        {rest, new_line, buffer} = trim_if_needed(rest, new_line, opts, buffer, acc)
-        tokenize(rest, new_line, opts, buffer, acc)
+        tokenize rest, new_line, opts, buffer, acc
    end
  end

@@ -53,24 +41,22 @@ defmodule EEx.Tokenizer do
    {marker, t} = retrieve_marker(t)

    case expr(t, line, []) do
-      {:error, _, _} = error ->
-        error
-
+      {:error, _, _} = error -> error
      {:ok, expr, new_line, rest} ->
        token = token_name(expr)
        {rest, new_line, buffer} = trim_if_needed(rest, new_line, opts, buffer, acc)
-        acc = tokenize_text(buffer, acc)
+        acc   = tokenize_text(buffer, acc)
        final = {token, line, marker, Enum.reverse(expr)}
-        tokenize(rest, new_line, opts, [], [final | acc])
+        tokenize rest, new_line, opts, [], [final | acc]
    end
  end

  defp tokenize('\n' ++ t, line, opts, buffer, acc) do
-    tokenize(t, line + 1, opts, [?\n | buffer], acc)
+    tokenize t, line + 1, opts, [?\n|buffer], acc
  end

-  defp tokenize([h | t], line, opts, buffer, acc) do
-    tokenize(t, line, opts, [h | buffer], acc)
+  defp tokenize([h|t], line, opts, buffer, acc) do
+    tokenize t, line, opts, [h|buffer], acc
  end

  defp tokenize([], _line, _opts, buffer, acc) do
@@ -79,8 +65,8 @@ defmodule EEx.Tokenizer do

  # Retrieve marker for <%

-  defp retrieve_marker([marker | t]) when marker in [?=, ?/, ?|] do
-    {[marker], t}
+  defp retrieve_marker('=' ++ t) do
+    {'=', t}
  end

  defp retrieve_marker(t) do
@@ -89,16 +75,16 @@ defmodule EEx.Tokenizer do

  # Tokenize an expression until we find %>

-  defp expr([?%, ?> | t], line, buffer) do
+  defp expr([?%, ?>|t], line, buffer) do
    {:ok, buffer, line, t}
  end

  defp expr('\n' ++ t, line, buffer) do
-    expr(t, line + 1, [?\n | buffer])
+    expr t, line + 1, [?\n|buffer]
  end

-  defp expr([h | t], line, buffer) do
-    expr(t, line, [h | buffer])
+  defp expr([h|t], line, buffer) do
+    expr t, line, [h|buffer]
  end

  defp expr([], line, _buffer) do
@@ -112,11 +98,11 @@ defmodule EEx.Tokenizer do
  # Middle tokens are marked with "->" or keywords
  # End tokens contain only the end word and optionally ")"

-  defp token_name([h | t]) when h in [?\s, ?\t, ?)] do
+  defp token_name([h|t]) when h in [?\s, ?\t, ?)] do
    token_name(t)
  end

-  defp token_name('od' ++ [h | _]) when h in [?\s, ?\t, ?)] do
+  defp token_name('od' ++ [h|_]) when h in [?\s, ?\t, ?)] do
    :start_expr
  end

@@ -129,8 +115,8 @@ defmodule EEx.Tokenizer do
    # token and, if so, it is not followed by an "end"
    # token. If this is the case, we are on a start expr.
    case :elixir_tokenizer.tokenize(rest, 1, file: "eex", check_terminators: false) do
-      {:ok, tokens} ->
-        tokens = Enum.reverse(tokens)
+      {:ok, _line, _column, tokens} ->
+        tokens   = Enum.reverse(tokens)
        fn_index = fn_index(tokens)

        if fn_index && end_index(tokens) > fn_index do
@@ -138,28 +124,27 @@ defmodule EEx.Tokenizer do
        else
          :middle_expr
        end
-
      _error ->
        :middle_expr
    end
  end

-  defp token_name('esle' ++ t), do: check_spaces(t, :middle_expr)
-  defp token_name('retfa' ++ t), do: check_spaces(t, :middle_expr)
-  defp token_name('hctac' ++ t), do: check_spaces(t, :middle_expr)
+  defp token_name('esle' ++ t),   do: check_spaces(t, :middle_expr)
+  defp token_name('retfa' ++ t),  do: check_spaces(t, :middle_expr)
+  defp token_name('hctac' ++ t),  do: check_spaces(t, :middle_expr)
  defp token_name('eucser' ++ t), do: check_spaces(t, :middle_expr)
-  defp token_name('dne' ++ t), do: check_spaces(t, :end_expr)
+  defp token_name('dne' ++ t),    do: check_spaces(t, :end_expr)

  defp token_name(_) do
    :expr
  end

  defp fn_index(tokens) do
-    Enum.find_index(tokens, fn
+    Enum.find_index tokens, fn
      {:fn_paren, _} -> true
-      {:fn, _} -> true
-      _ -> false
-    end)
+      {:fn, _}       -> true
+      _                -> false
+    end
  end

  defp end_index(tokens) do
@@ -188,14 +173,13 @@ defmodule EEx.Tokenizer do
  # If trim mode is enabled and the token is on a line with
  # only itself and whitespace, trim the whitespace around it,
  # including the line break following it if there is one.
+
  defp trim_if_needed(rest, line, opts, buffer, acc) do
    original = {rest, line, buffer}
-
    if opts[:trim] do
      case {trim_left(buffer, acc), trim_right(rest, line)} do
        {{true, new_buffer}, {true, new_rest, new_line}} ->
          {new_rest, new_line, new_buffer}
-
        _ ->
          original
      end
@@ -206,7 +190,7 @@ defmodule EEx.Tokenizer do

  defp trim_left(buffer, acc) do
    case {trim_whitespace(buffer), acc} do
-      {[?\n | _] = trimmed_buffer, _} -> {true, trimmed_buffer}
+      {[?\n|_] = trimmed_buffer, _} -> {true, trimmed_buffer}
      {[], []} -> {true, []}
      _ -> {false, buffer}
    end
@@ -214,14 +198,14 @@ defmodule EEx.Tokenizer do

  defp trim_right(rest, line) do
    case trim_whitespace(rest) do
-      [?\r, ?\n | trimmed_rest] -> {true, trimmed_rest, line + 1}
-      [?\n | trimmed_rest] -> {true, trimmed_rest, line + 1}
+      [?\r, ?\n|trimmed_rest] -> {true, trimmed_rest, line + 1}
+      [?\n|trimmed_rest] -> {true, trimmed_rest, line + 1}
      [] -> {true, [], line}
      _ -> {false, rest, line}
    end
  end

-  defp trim_whitespace([h | t]) when h == ?\s or h == ?\t do
+  defp trim_whitespace([h|t]) when h == ?\s or h == ?\t do
    trim_whitespace(t)
  end

@@ -1,11 +1,9 @@
-defmodule EEx.MixProject do
+defmodule EEx.Mixfile do
  use Mix.Project

  def project do
-    [
-      app: :eex,
-      version: System.version(),
-      build_per_environment: false
-    ]
+    [app: :eex,
+     version: System.version,
+     build_per_environment: false]
  end
 end
@@ -1,48 +1,36 @@
-Code.require_file("../test_helper.exs", __DIR__)
+Code.require_file "../test_helper.exs", __DIR__

 defmodule EEx.SmartEngineTest do
-  # TODO: Make this async: true once capture_io is removed
-  use ExUnit.Case
+  use ExUnit.Case, async: true

  test "evaluates simple string" do
-    assert_eval("foo bar", "foo bar")
+    assert_eval "foo bar", "foo bar"
  end

  test "evaluates with assigns as keywords" do
-    assert_eval("1", "<%= @foo %>", assigns: [foo: 1])
+    assert_eval "1", "<%= @foo %>", assigns: [foo: 1]
  end

  test "evaluates with assigns as a map" do
-    assert_eval("1", "<%= @foo %>", assigns: %{foo: 1})
-  end
-
-  test "error with missing assigns" do
-    stderr =
-      ExUnit.CaptureIO.capture_io(:stderr, fn ->
-        assert_eval("", "<%= @foo %>", assigns: %{})
-      end)
-
-    assert stderr =~ "assign @foo not available in EEx template"
+    assert_eval "1", "<%= @foo %>", assigns: %{foo: 1}
  end

  test "evaluates with loops" do
-    assert_eval("1\n2\n3\n", "<%= for x <- [1, 2, 3] do %><%= x %>\n<% end %>")
+    assert_eval "1\n2\n3\n", "<%= for x <- [1, 2, 3] do %><%= x %>\n<% end %>"
  end

-  test "preserves line numbers" do
+  test "compiled preserved line numbers" do
    result = EEx.compile_string("<%= @hello %>", engine: EEx.SmartEngine)
-
    Macro.prewalk(result, fn
      {_left, meta, _right} ->
        assert Keyword.get(meta, :line, 0) in [0, 1]
-
      _ ->
        :ok
    end)
  end

  defp assert_eval(expected, actual, binding \\ []) do
-    result = EEx.eval_string(actual, binding, file: __ENV__.file, engine: EEx.SmartEngine)
+    result = EEx.eval_string(actual, binding, file: __ENV__.file)
    assert result == expected
  end
 end
@@ -1,4 +1,4 @@
-Code.require_file("../test_helper.exs", __DIR__)
+Code.require_file "../test_helper.exs", __DIR__

 defmodule EEx.TokenizerTest do
  use ExUnit.Case, async: true
@@ -13,102 +13,86 @@ defmodule EEx.TokenizerTest do
  end

  test "strings with embedded code" do
-    assert T.tokenize('foo <% bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '', ' bar '}]}
+    assert T.tokenize('foo <% bar %>', 1) ==
+           {:ok, [{:text, 'foo '}, {:expr, 1, '', ' bar '}]}
  end

  test "strings with embedded equals code" do
-    assert T.tokenize('foo <%= bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '=', ' bar '}]}
-  end
-
-  test "strings with embedded slash code" do
-    assert T.tokenize('foo <%/ bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '/', ' bar '}]}
-  end
-
-  test "strings with embedded pipe code" do
-    assert T.tokenize('foo <%| bar %>', 1) == {:ok, [{:text, 'foo '}, {:expr, 1, '|', ' bar '}]}
+    assert T.tokenize('foo <%= bar %>', 1) ==
+           {:ok, [{:text, 'foo '}, {:expr, 1, '=', ' bar '}]}
  end

  test "strings with more than one line" do
-    assert T.tokenize('foo\n<%= bar %>', 1) == {:ok, [{:text, 'foo\n'}, {:expr, 2, '=', ' bar '}]}
+    assert T.tokenize('foo\n<%= bar %>', 1) ==
+           {:ok, [{:text, 'foo\n'}, {:expr, 2, '=', ' bar '}]}
  end

  test "strings with more than one line and expression with more than one line" do
    string = '''
-    foo <%= bar
+foo <%= bar

-    baz %>
-    <% foo %>
-    '''
+baz %>
+<% foo %>
+'''

-    exprs = [
+    assert T.tokenize(string, 1) == {:ok, [
      {:text, 'foo '},
      {:expr, 1, '=', ' bar\n\nbaz '},
      {:text, '\n'},
      {:expr, 4, '', ' foo '},
      {:text, '\n'}
-    ]
-
-    assert T.tokenize(string, 1) == {:ok, exprs}
+    ]}
  end

  test "quotation" do
-    assert T.tokenize('foo <%% true %>', 1) == {:ok, [{:text, 'foo <% true %>'}]}
+    assert T.tokenize('foo <%% true %>', 1) == {:ok, [
+      {:text, 'foo <% true %>'}
+    ]}
  end

  test "quotation with do/end" do
-    assert T.tokenize('foo <%% true do %>bar<%% end %>', 1) ==
-             {:ok, [{:text, 'foo <% true do %>bar<% end %>'}]}
+    assert T.tokenize('foo <%% true do %>bar<%% end %>', 1) == {:ok, [
+      {:text, 'foo <% true do %>bar<% end %>'}
+    ]}
  end

  test "quotation with interpolation" do
-    exprs = [
+    assert T.tokenize('a <%% b <%= c %> <%= d %> e %> f', 1) == {:ok, [
      {:text, 'a <% b '},
      {:expr, 1, '=', ' c '},
      {:text, ' '},
      {:expr, 1, '=', ' d '},
      {:text, ' e %> f'}
-    ]
+    ]}

-    assert T.tokenize('a <%% b <%= c %> <%= d %> e %> f', 1) == {:ok, exprs}
-  end
-
-  test "improperly formatted quotation with interpolation" do
-    exprs = [
+    assert T.tokenize('<%%% a <%%= b %> c %>', 1) == {:ok, [
      {:text, '<%% a <%= b %> c %>'}
-    ]
-
-    assert T.tokenize('<%%% a <%%= b %> c %>', 1) == {:ok, exprs}
+    ]}
  end

  test "comments" do
-    exprs = [
+    assert T.tokenize('foo <%# true %>', 1) == {:ok, [
      {:text, 'foo '}
-    ]
-
-    assert T.tokenize('foo <%# true %>', 1) == {:ok, exprs}
+    ]}
  end

  test "comments with do/end" do
-    exprs = [
+    assert T.tokenize('foo <%# true do %>bar<%# end %>', 1) == {:ok, [
      {:text, 'foo bar'}
-    ]
-
-    assert T.tokenize('foo <%# true do %>bar<%# end %>', 1) == {:ok, exprs}
+    ]}
  end

  test "strings with embedded do end" do
-    exprs = [
+    assert T.tokenize('foo <% if true do %>bar<% end %>', 1) == {:ok, [
      {:text, 'foo '},
      {:start_expr, 1, '', ' if true do '},
      {:text, 'bar'},
      {:end_expr, 1, '', ' end '}
-    ]
-
-    assert T.tokenize('foo <% if true do %>bar<% end %>', 1) == {:ok, exprs}
+    ]}
  end

  test "strings with embedded -> end" do
-    exprs = [
+    assert T.tokenize('foo <% cond do %><% false -> %>bar<% true -> %>baz<% end %>', 1) == {:ok, [
      {:text, 'foo '},
      {:start_expr, 1, '', ' cond do '},
      {:middle_expr, 1, '', ' false -> '},
@@ -116,65 +100,51 @@ defmodule EEx.TokenizerTest do
      {:middle_expr, 1, '', ' true -> '},
      {:text, 'baz'},
      {:end_expr, 1, '', ' end '}
-    ]
-
-    assert T.tokenize('foo <% cond do %><% false -> %>bar<% true -> %>baz<% end %>', 1) ==
-             {:ok, exprs}
+    ]}
  end

  test "strings with embedded keywords blocks" do
-    exprs = [
+    assert T.tokenize('foo <% if true do %>bar<% else %>baz<% end %>', 1) == {:ok, [
      {:text, 'foo '},
      {:start_expr, 1, '', ' if true do '},
      {:text, 'bar'},
      {:middle_expr, 1, '', ' else '},
      {:text, 'baz'},
      {:end_expr, 1, '', ' end '}
-    ]
-
-    assert T.tokenize('foo <% if true do %>bar<% else %>baz<% end %>', 1) == {:ok, exprs}
+    ]}
  end

  test "trim mode" do
    template = '\t<%= if true do %> \n TRUE \n  <% else %>\n FALSE \n  <% end %>  '
-
-    exprs = [
+    assert T.tokenize(template, 1, trim: true) == {:ok, [
      {:start_expr, 1, '=', ' if true do '},
      {:text, ' TRUE \n'},
      {:middle_expr, 3, '', ' else '},
      {:text, ' FALSE \n'},
      {:end_expr, 5, '', ' end '}
-    ]
-
-    assert T.tokenize(template, 1, trim: true) == {:ok, exprs}
+    ]}
  end

  test "trim mode with comment" do
-    exprs = [
+    assert T.tokenize('  <%# comment %>  \n123', 1, trim: true) == {:ok, [
      {:text, '123'}
-    ]
-
-    assert T.tokenize('  <%# comment %>  \n123', 1, trim: true) == {:ok, exprs}
+    ]}
  end

  test "trim mode with CRLF" do
-    exprs = [
+    assert T.tokenize('0\r\n  <%= 12 %>  \r\n34', 1, trim: true) == {:ok, [
      {:text, '0\r\n'},
      {:expr, 2, '=', ' 12 '},
      {:text, '34'}
-    ]
-
-    assert T.tokenize('0\r\n  <%= 12 %>  \r\n34', 1, trim: true) == {:ok, exprs}
+    ]}
  end

  test "trim mode set to false" do
-    exprs = [
+    assert T.tokenize(' <%= 12 %> \n', 1, trim: false) == {:ok, [
      {:text, ' '},
      {:expr, 1, '=', ' 12 '},
      {:text, ' \n'}
-    ]
-
-    assert T.tokenize(' <%= 12 %> \n', 1, trim: false) == {:ok, exprs}
+    ]}
  end

  test "trim mode no false positives" do
@@ -188,6 +158,5 @@ defmodule EEx.TokenizerTest do

  test "raise syntax error when there is start mark and no end mark" do
    assert T.tokenize('foo <% :bar', 1) == {:error, 1, "missing token '%>'"}
-    assert T.tokenize('<%# true ', 1) == {:error, 1, "missing token '%>'"}
  end
 end
@@ -1,36 +1,39 @@
-Code.require_file("test_helper.exs", __DIR__)
+Code.require_file "test_helper.exs", __DIR__

 require EEx

 defmodule EExTest.Compiled do
  def before_compile do
-    {__ENV__.line, hd(tl(get_stacktrace()))}
+    fill_in_stacktrace
+    {__ENV__.line, hd(tl(System.stacktrace))}
  end

-  EEx.function_from_string(:def, :string_sample, "<%= a + b %>", [:a, :b])
+  EEx.function_from_string :def, :string_sample, "<%= a + b %>", [:a, :b]

  filename = Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")
-  EEx.function_from_file(:defp, :private_file_sample, filename, [:bar])
+  EEx.function_from_file :defp, :private_file_sample, filename, [:bar]

  filename = Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")
-  EEx.function_from_file(:def, :public_file_sample, filename, [:bar])
+  EEx.function_from_file :def, :public_file_sample, filename, [:bar]

  def file_sample(arg), do: private_file_sample(arg)

  def after_compile do
-    {__ENV__.line, hd(tl(get_stacktrace()))}
+    fill_in_stacktrace
+    {__ENV__.line, hd(tl(System.stacktrace))}
  end

  @file "unknown"
  def unknown do
-    {__ENV__.line, hd(tl(get_stacktrace()))}
+    fill_in_stacktrace
+    {__ENV__.line, hd(tl(System.stacktrace))}
  end

-  defp get_stacktrace do
+  defp fill_in_stacktrace do
    try do
-      :erlang.error("failed")
-    rescue
-      _ -> __STACKTRACE__
+      :erlang.error "failed"
+    catch
+      :error, _ -> System.stacktrace
    end
  end
 end
@@ -50,439 +53,355 @@ defmodule EExTest do
  doctest EEx.Engine
  doctest EEx.SmartEngine

-  describe "evaluates" do
-    test "simple string" do
-      assert_eval("foo bar", "foo bar")
-    end
+  test "evaluates simple string" do
+    assert_eval "foo bar", "foo bar"
+  end

-    test "Unicode" do
-      template = """
-        • <%= "•" %> •
-        <%= "Jößé Vâlìm" %> Jößé Vâlìm
-      """
+  test "evaluates with embedded" do
+    assert_eval "foo bar", "foo <%= :bar %>"
+  end

-      assert_eval("  • • •\n  Jößé Vâlìm Jößé Vâlìm\n", template)
-    end
+  test "evaluates with embedded and the binding" do
+    assert EEx.eval_string("foo <%= bar %>", [bar: 1]) == "foo 1"
+  end

-    test "trim mode" do
-      string = "<%= 123 %> \n456\n  <%= 789 %>"
-      expected = "123456\n789"
-      assert_eval(expected, string, [], trim: true)
-    end
+  test "evaluates with embedded do end" do
+    assert_eval "foo bar", "foo <%= if true do %>bar<% end %>"
+  end

-    test "trim mode with middle expression" do
-      string = """
-      <%= cond do %>
-      <% false -> %>
-        this
-      <% true -> %>
-        that
-      <% end %>
-      """
+  test "evaluates with embedded do end and eval the expression" do
+    assert_eval "foo ", "foo <%= if false do %>bar<% end %>"
+  end

-      expected = "  that\n"
-      assert_eval(expected, string, [], trim: true)
-    end
+  test "evaluates with embedded do end and nested print expression" do
+    assert_eval "foo bar", "foo <%= if true do %><%= :bar %><% end %>"
+  end

-    test "embedded code" do
-      assert_eval("foo bar", "foo <%= :bar %>")
-    end
+  test "evaluates with embedded do end and nested expressions" do
+    assert_eval "foo bar baz", "foo <%= if true do %>bar <% Process.put(:eex_text, 1) %><%= :baz %><% end %>"
+    assert Process.get(:eex_text) == 1
+  end

-    test "embedded code with binding" do
-      assert EEx.eval_string("foo <%= bar %>", bar: 1) == "foo 1"
-    end
+  test "evaluates with embedded middle expression" do
+    assert_eval "foo bar", "foo <%= if true do %>bar<% else %>baz<% end %>"
+  end

-    test "embedded code with do end when true" do
-      assert_eval("foo bar", "foo <%= if true do %>bar<% end %>")
-    end
+  test "evaluates with embedded middle expression and eval the expression" do
+    assert_eval "foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>"
+  end

-    test "embedded code with do end when false" do
-      assert_eval("foo ", "foo <%= if false do %>bar<% end %>")
-    end
+  test "evaluates with nested start expression" do
+    assert_eval "foo bar", "foo <%= if true do %><%= if true do %>bar<% end %><% end %>"
+  end

-    test "embedded code with do end and expression" do
-      assert_eval("foo bar", "foo <%= if true do %><%= :bar %><% end %>")
-    end
+  test "evaluates with nested middle expression" do
+    assert_eval "foo baz", "foo <%= if true do %><%= if false do %>bar<% else %>baz<% end %><% end %>"
+  end

-    test "embedded code with do end and multiple expressions" do
-      assert_eval(
-        "foo bar baz",
-        "foo <%= if true do %>bar <% Process.put(:eex_text, 1) %><%= :baz %><% end %>"
-      )
+  test "evaluates with parentheses after end in end token" do
+    assert_eval " 101  102  103 ", "<%= Enum.map([1,2,3], (fn x -> %> <%= 100 + x %> <% end) ) %>"
+  end

-      assert Process.get(:eex_text) == 1
-    end
+  test "evaluates with defined variable" do
+    assert_eval "foo 1", "foo <% bar = 1 %><%= bar %>"
+  end

-    test "embedded code with middle expression" do
-      assert_eval("foo bar", "foo <%= if true do %>bar<% else %>baz<% end %>")
-    end
+  test "evaluates with require code" do
+    assert_eval "foo 1,2,3", "foo <% require Enum, as: E %><%= E.join [1, 2, 3], \",\" %>"
+  end

-    test "embedded code with evaluated middle expression" do
-      assert_eval("foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>")
-    end
+  test "evaluates with end of token" do
+    assert_eval "foo bar %>", "foo bar %>"
+  end

-    test "embedded code with nested do end" do
-      assert_eval("foo bar", "foo <%= if true do %><%= if true do %>bar<% end %><% end %>")
-    end
-
-    test "embedded code with nested do end with middle expression" do
-      assert_eval(
-        "foo baz",
-        "foo <%= if true do %><%= if false do %>bar<% else %>baz<% end %><% end %>"
-      )
-    end
-
-    test "embedded code with parentheses after end in end token" do
-      assert_eval(
-        " 101  102  103 ",
-        "<%= Enum.map([1, 2, 3], (fn x -> %> <%= 100 + x %> <% end) ) %>"
-      )
-    end
-
-    test "embedded code with variable definition" do
-      assert_eval("foo 1", "foo <% bar = 1 %><%= bar %>")
-    end
-
-    test "embedded code with require" do
-      assert_eval("foo 1,2,3", "foo <% require Enum, as: E %><%= E.join [1, 2, 3], \",\" %>")
-    end
-
-    test "with end of token" do
-      assert_eval("foo bar %>", "foo bar %>")
+  test "raises a syntax error when the token is invalid" do
+    assert_raise EEx.SyntaxError, "nofile:1: missing token '%>'", fn ->
+      EEx.compile_string "foo <%= bar"
    end
  end

-  describe "raises syntax errors" do
-    test "when the token is invalid" do
-      assert_raise EEx.SyntaxError, "nofile:1: missing token '%>'", fn ->
-        EEx.compile_string("foo <%= bar")
-      end
-    end
-
-    test "when middle expression is found without a start expression" do
-      assert_raise EEx.SyntaxError, "nofile:1: unexpected middle of expression <% else %>", fn ->
-        EEx.compile_string("<% if true %> foo<% else %>bar<% end %>")
-      end
-    end
-
-    test "when end expression is found without a start expression" do
-      assert_raise EEx.SyntaxError, "nofile:1: unexpected end of expression <% end %>", fn ->
-        EEx.compile_string("foo <% end %>")
-      end
-    end
-
-    test "when start expression is found without an end expression" do
-      msg = "nofile:2: unexpected end of string, expected a closing '<% end %>'"
-
-      assert_raise EEx.SyntaxError, msg, fn ->
-        EEx.compile_string("foo\n<% if true do %>")
-      end
-    end
-
-    test "when nested end expression is found without a start expression" do
-      assert_raise EEx.SyntaxError, "nofile:1: unexpected end of expression <% end %>", fn ->
-        EEx.compile_string("foo <% if true do %><% end %><% end %>")
-      end
-    end
-
-    test "when middle expression has a modifier" do
-      assert ExUnit.CaptureIO.capture_io(:stderr, fn ->
-               EEx.compile_string("foo <%= if true do %>true<%= else %>false<% end %>")
-             end) =~ ~s[unexpected beginning of EEx tag \"<%=\" on \"<%= else %>\"]
-    end
-
-    test "when end expression has a modifier" do
-      assert ExUnit.CaptureIO.capture_io(:stderr, fn ->
-               EEx.compile_string("foo <%= if true do %>true<% else %>false<%= end %>")
-             end) =~
-               ~s[unexpected beginning of EEx tag \"<%=\" on end of expression \"<%= end %>\"]
-    end
-
-    test "when trying to use marker '/' without implementation" do
-      msg =
-        ~r/unsupported EEx syntax <%\/ %> \(the syntax is valid but not supported by the current EEx engine\)/
-
-      assert_raise EEx.SyntaxError, msg, fn ->
-        EEx.compile_string("<%/ true %>")
-      end
-    end
-
-    test "when trying to use marker '|' without implementation" do
-      msg =
-        ~r/unsupported EEx syntax <%| %> \(the syntax is valid but not supported by the current EEx engine\)/
-
-      assert_raise EEx.SyntaxError, msg, fn ->
-        EEx.compile_string("<%| true %>")
-      end
+  test "raises a syntax error when end expression is found without a start expression" do
+    assert_raise EEx.SyntaxError, "nofile:1: unexpected token ' end '",  fn ->
+      EEx.compile_string "foo <% end %>"
    end
  end

-  describe "environment" do
-    test "respects line numbers" do
-      expected = """
-      foo
-      2
-      """
-
-      string = """
-      foo
-      <%= __ENV__.line %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "respects line numbers inside nested expressions" do
-      expected = """
-      foo
-
-      3
-
-      5
-      """
-
-      string = """
-      foo
-      <%= if true do %>
-      <%= __ENV__.line %>
-      <% end %>
-      <%= __ENV__.line %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "respects line numbers inside start expression" do
-      expected = """
-      foo
-
-      true
-
-      5
-      """
-
-      string = """
-      foo
-      <%= if __ENV__.line == 2 do %>
-      <%= true %>
-      <% end %>
-      <%= __ENV__.line %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "respects line numbers inside middle expression with ->" do
-      expected = """
-      foo
-
-      true
-
-      7
-      """
-
-      string = """
-      foo
-      <%= cond do %>
-      <% false -> %> false
-      <% __ENV__.line == 4 -> %>
-      <%= true %>
-      <% end %>
-      <%= __ENV__.line %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "respects line number inside middle expressions with keywords" do
-      expected = """
-      foo
-
-      5
-
-      7
-      """
-
-      string = """
-      foo
-      <%= if false do %>
-      <%= __ENV__.line %>
-      <% else %>
-      <%= __ENV__.line %>
-      <% end %>
-      <%= __ENV__.line %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "respects files" do
-      assert_eval("sample.ex", "<%= __ENV__.file %>", [], file: "sample.ex")
+  test "raises a syntax error when start expression is found without an end expression" do
+    assert_raise EEx.SyntaxError, "nofile:2: unexpected end of string, expected a closing '<% end %>'", fn ->
+      EEx.compile_string "foo\n<% if true do %>"
    end
  end

-  describe "clauses" do
-    test "inside functions" do
-      expected = """
-
-      Number 1
-
-      Number 2
-
-      Number 3
-
-      """
-
-      string = """
-      <%= Enum.map [1, 2, 3], fn x -> %>
-      Number <%= x %>
-      <% end %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "inside cond" do
-      expected = """
-      foo
-
-      true
-
-      """
-
-      string = """
-      foo
-      <%= cond do %>
-      <% false -> %> false
-      <% fn -> 1 end -> %>
-      <%= true %>
-      <% end %>
-      """
-
-      assert_eval(expected, string)
-    end
-
-    test "inside cond with do end" do
-      string = """
-      <% y = ["a", "b", "c"] %>
-      <%= cond do %>
-       <% "a" in y -> %>
-        Good
-       <% true -> %>
-        <% if true do %>true<% else %>false<% end %>
-        Bad
-      <% end %>
-      """
-
-      assert_eval("\n\n  Good\n \n", string)
+  test "raises a syntax error when nested end expression is found without a start expression" do
+    assert_raise EEx.SyntaxError, "nofile:1: unexpected token ' end '", fn ->
+      EEx.compile_string "foo <% if true do %><% end %><% end %>"
    end
  end

-  describe "buffers" do
-    test "unused buffers are kept out" do
-      string = """
-      <%= 123 %>
-      <% if true do %>
-        <%= 456 %>
-      <% end %>
-      <%= 789 %>
-      """
+  test "respects line numbers" do
+    expected = """
+foo
+2
+"""

-      assert_eval("123\n\n789\n", string)
-    end
+    string = """
+foo
+<%= __ENV__.line %>
+"""

-    test "inside comprehensions" do
-      string = """
-      <%= for _name <- packages || [] do %>
-      <% end %>
-      <%= all || :done %>
-      """
+    assert_eval expected, string
+  end

-      assert_eval("\ndone\n", string, packages: nil, all: nil)
+  test "respects line numbers inside nested expressions" do
+    expected = """
+foo
+
+3
+
+5
+"""
+
+    string = """
+foo
+<%= if true do %>
+<%= __ENV__.line %>
+<% end %>
+<%= __ENV__.line %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "respects line numbers inside start expression" do
+    expected = """
+foo
+
+true
+
+5
+"""
+
+    string = """
+foo
+<%= if __ENV__.line == 2 do %>
+<%= true %>
+<% end %>
+<%= __ENV__.line %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "respects line numbers inside middle expression with ->" do
+    expected = """
+foo
+
+true
+
+7
+"""
+
+    string = """
+foo
+<%= cond do %>
+<% false -> %> false
+<% __ENV__.line == 4 -> %>
+<%= true %>
+<% end %>
+<%= __ENV__.line %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "respects line number inside middle expressions with keywords" do
+    expected = """
+foo
+
+5
+
+7
+"""
+
+    string = """
+foo
+<%= if false do %>
+<%= __ENV__.line %>
+<% else %>
+<%= __ENV__.line %>
+<% end %>
+<%= __ENV__.line %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "respects files" do
+    assert_eval "sample.ex", "<%= __ENV__.file %>", [], file: "sample.ex"
+  end
+
+  test "properly handle functions" do
+    expected = """
+
+Number 1
+
+Number 2
+
+Number 3
+
+"""
+
+    string = """
+<%= Enum.map [1, 2, 3], fn x -> %>
+Number <%= x %>
+<% end %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "properly handle functions on the left side of clauses" do
+    expected = """
+foo
+
+true
+
+"""
+
+    string = """
+foo
+<%= cond do %>
+<% false -> %> false
+<% fn -> 1 end -> %>
+<%= true %>
+<% end %>
+"""
+
+    assert_eval expected, string
+  end
+
+  test "evaluates nested do expressions" do
+    string = """
+    <% y = ["a", "b", "c"] %>
+    <%= cond do %>
+     <% "a" in y -> %>
+      Good
+     <% true -> %>
+      <% if true do %>true<% else %>false<% end %>
+      Bad
+    <% end %>
+    """
+
+    assert_eval "\n\n  Good\n \n", string
+  end
+
+  test "evaluates expressions with buffers" do
+    string = """
+    <%= 123 %>
+    <% if true do %>
+      <%= 456 %>
+    <% end %>
+    <%= 789 %>
+    """
+
+    assert_eval "123\n\n789\n", string
+  end
+
+  test "for comprehensions" do
+    string = """
+    <%= for _name <- packages || [] do %>
+    <% end %>
+    <%= all || :done %>
+    """
+    assert_eval "\ndone\n", string, packages: nil, all: nil
+  end
+
+  test "unicode" do
+    template = """
+      • <%= "•" %> •
+      <%= "Jößé Vâlìm" %> Jößé Vâlìm
+    """
+    result = EEx.eval_string(template)
+    assert result == "  • • •\n  Jößé Vâlìm Jößé Vâlìm\n"
+  end
+
+  test "trim mode" do
+    string = "<%= 123 %> \n456\n  <%= 789 %>"
+    expected = "123456\n789"
+    assert_eval expected, string, [], trim: true
+  end
+
+  test "evaluates the source from a given file" do
+    filename = Path.join(__DIR__, "fixtures/eex_template.eex")
+    result = EEx.eval_file(filename)
+    assert result == "foo bar.\n"
+  end
+
+  test "evaluates the source from a given file with bindings" do
+    filename = Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")
+    result = EEx.eval_file(filename, [bar: 1])
+    assert result == "foo 1\n"
+  end
+
+  test "raises an Exception when there's an error with the given file" do
+    assert_raise File.Error, "could not read file non-existent.eex: no such file or directory", fn ->
+      filename = "non-existent.eex"
+      EEx.compile_file(filename)
    end
  end

-  describe "from file" do
-    test "evaluates the source" do
-      filename = Path.join(__DIR__, "fixtures/eex_template.eex")
-      result = EEx.eval_file(filename)
-      assert_normalized_newline_equal("foo bar.\n", result)
-    end
-
-    test "evaluates the source with bindings" do
-      filename = Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")
-      result = EEx.eval_file(filename, bar: 1)
-      assert_normalized_newline_equal("foo 1\n", result)
-    end
-
-    test "raises an Exception when file is missing" do
-      msg = "could not read file \"non-existent.eex\": no such file or directory"
-
-      assert_raise File.Error, msg, fn ->
-        filename = "non-existent.eex"
-        EEx.compile_file(filename)
-      end
-    end
-
-    test "sets external resource attribute" do
-      assert EExTest.Compiled.__info__(:attributes)[:external_resource] ==
-               [Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")]
-    end
+  test "sets external resource attribute" do
+    assert EExTest.Compiled.__info__(:attributes)[:external_resource] ==
+           [Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")]
  end

-  describe "precompiled" do
-    test "from string" do
-      assert EExTest.Compiled.string_sample(1, 2) == "3"
-    end
+  test "defined from string" do
+    assert EExTest.Compiled.string_sample(1, 2) == "3"
+  end

-    test "from file" do
-      assert_normalized_newline_equal("foo 1\n", EExTest.Compiled.file_sample(1))
-      assert_normalized_newline_equal("foo 1\n", EExTest.Compiled.public_file_sample(1))
-    end
+  test "defined from file" do
+    assert EExTest.Compiled.file_sample(1) == "foo 1\n"
+    assert EExTest.Compiled.public_file_sample(1) == "foo 1\n"
+  end

-    test "from file does not affect backtrace" do
-      file = to_charlist(Path.relative_to_cwd(__ENV__.file))
+  test "defined from file do not affect backtrace" do
+    assert EExTest.Compiled.before_compile ==
+      {8,
+        {EExTest.Compiled,
+          :before_compile,
+          0,
+          [file: to_char_list(Path.relative_to_cwd(__ENV__.file)), line: 7]
+       }
+     }

-      assert EExTest.Compiled.before_compile() ==
-               {7, {EExTest.Compiled, :before_compile, 0, [file: file, line: 7]}}
+    assert EExTest.Compiled.after_compile ==
+      {23,
+        {EExTest.Compiled,
+          :after_compile,
+          0,
+          [file: to_char_list(Path.relative_to_cwd(__ENV__.file)), line: 22]
+       }
+     }

-      assert EExTest.Compiled.after_compile() ==
-               {21, {EExTest.Compiled, :after_compile, 0, [file: file, line: 21]}}
-
-      assert EExTest.Compiled.unknown() ==
-               {26, {EExTest.Compiled, :unknown, 0, [file: 'unknown', line: 26]}}
-    end
+    assert EExTest.Compiled.unknown ==
+      {29,
+        {EExTest.Compiled,
+          :unknown,
+          0,
+          [file: 'unknown', line: 28]
+       }
+     }
  end

  defmodule TestEngine do
    @behaviour EEx.Engine

-    def init(_opts) do
-      "INIT"
-    end
-
    def handle_body(body) do
-      "BODY(#{body})"
-    end
-
-    def handle_begin(_) do
-      "BEGIN"
-    end
-
-    def handle_end(buffer) do
-      buffer <> ":END"
+      {:wrapped, body}
    end

    def handle_text(buffer, text) do
-      buffer <> ":TEXT(#{String.trim(text)})"
-    end
-
-    def handle_expr(buffer, "/", expr) do
-      buffer <> ":DIV(#{Macro.to_string(expr)})"
-    end
-
-    def handle_expr(buffer, "=", expr) do
-      buffer <> ":EQUAL(#{Macro.to_string(expr)})"
+      EEx.Engine.handle_text(buffer, text)
    end

    def handle_expr(buffer, mark, expr) do
@@ -490,41 +409,13 @@ defmodule EExTest do
    end
  end

-  describe "custom engines" do
-    test "text" do
-      assert_eval("BODY(INIT:TEXT(foo))", "foo", [], engine: TestEngine)
-    end
-
-    test "custom marker" do
-      assert_eval("BODY(INIT:TEXT(foo):DIV(:bar))", "foo <%/ :bar %>", [], engine: TestEngine)
-    end
-
-    test "begin/end" do
-      assert_eval(
-        ~s[BODY(INIT:TEXT(foo):EQUAL(if() do\n  "BEGIN:TEXT(this):END"\nelse\n  "BEGIN:TEXT(that):END"\nend))],
-        "foo <%= if do %>this<% else %>that<% end %>",
-        [],
-        engine: TestEngine
-      )
-    end
-
-    test "not implemented custom marker" do
-      msg =
-        ~r/unsupported EEx syntax <%| %> \(the syntax is valid but not supported by the current EEx engine\)/
-
-      assert_raise EEx.SyntaxError, msg, fn ->
-        assert_eval({:wrapped, "foo baz"}, "foo <%| :bar %>", [], engine: TestEngine)
-      end
-    end
+  test "calls handle_body" do
+    assert {:wrapped, "foo"} = EEx.eval_string("foo", [], engine: TestEngine)
  end

  defp assert_eval(expected, actual, binding \\ [], opts \\ []) do
-    opts = Enum.into([file: __ENV__.file, engine: opts[:engine] || EEx.Engine], opts)
+    opts = Enum.into [file: __ENV__.file, engine: EEx.Engine], opts
    result = EEx.eval_string(actual, binding, opts)
    assert result == expected
  end
-
-  defp assert_normalized_newline_equal(expected, actual) do
-    assert String.replace(expected, "\r\n", "\n") == String.replace(actual, "\r\n", "\n")
-  end
 end
@@ -1 +1 @@
-ExUnit.start(trace: "--trace" in System.argv())
+ExUnit.start [trace: "--trace" in System.argv]
@@ -1,19 +0,0 @@
-{'src/*', [
-  warn_unused_vars,
-  warn_export_all,
-  warn_shadow_vars,
-  warn_unused_import,
-  warn_unused_function,
-  warn_bif_clash,
-  warn_unused_record,
-  warn_deprecated_function,
-  warn_obsolete_guard,
-  strict_validation,
-  warn_exported_vars,
-  %% warn_export_vars,
-  %% warn_missing_spec,
-  %% warn_untyped_record,
-  %% warnings_as_errors,
-  debug_info,
-  {outdir, "ebin/"}
-]}.
@@ -1,91 +0,0 @@
-# Returns config for Elixir docs
-[
-  extras: Path.wildcard("lib/elixir/pages/*.md"),
-  groups_for_modules: [
-    # [Kernel, Kernel.SpecialForms],
-
-    "Basic Types": [
-      Atom,
-      Base,
-      Bitwise,
-      Calendar,
-      Calendar.ISO,
-      Date,
-      DateTime,
-      Exception,
-      Float,
-      Function,
-      Integer,
-      NaiveDateTime,
-      Record,
-      Regex,
-      String,
-      Time,
-      Tuple,
-      URI,
-      Version
-    ],
-    "Collections & Enumerables": [
-      Access,
-      Date.Range,
-      Enum,
-      Keyword,
-      List,
-      Map,
-      MapSet,
-      Range,
-      Stream
-    ],
-    "IO & System": [
-      File,
-      File.Stat,
-      File.Stream,
-      IO,
-      IO.ANSI,
-      IO.Stream,
-      OptionParser,
-      Path,
-      Port,
-      StringIO,
-      System
-    ],
-    "Modules & Code": [
-      Code,
-      Kernel.ParallelCompiler,
-      Macro,
-      Macro.Env,
-      Module
-    ],
-    "Processes & Applications": [
-      Agent,
-      Application,
-      DynamicSupervisor,
-      GenServer,
-      Node,
-      Process,
-      Registry,
-      Supervisor,
-      Task,
-      Task.Supervisor
-    ],
-    Protocols: [
-      Collectable,
-      Enumerable,
-      Inspect,
-      Inspect.Algebra,
-      Inspect.Opts,
-      List.Chars,
-      Protocol,
-      String.Chars
-    ],
-    Deprecated: [
-      Behaviour,
-      Dict,
-      GenEvent,
-      HashDict,
-      HashSet,
-      Set,
-      Supervisor.Spec
-    ]
-  ]
-]
@@ -1,13 +0,0 @@
-#!/usr/bin/env escript
-%% -*- erlang -*-
-
-main([Source, Target, Version]) ->
-  {ok, [{application, Name, Props0}]} = file:consult(Source),
-  Ebin = filename:dirname(Target),
-  Files = filelib:wildcard(filename:join(Ebin, "*.beam")),
-  Mods = [list_to_atom(filename:basename(F, ".beam")) || F <- Files],
-  Props1 = lists:keyreplace(modules, 1, Props0, {modules, Mods}),
-  Props = lists:keyreplace(vsn, 1, Props1, {vsn, Version}),
-  AppDef = io_lib:format("~tp.~n", [{application, Name, Props}]),
-  ok = file:write_file(Target, AppDef),
-  io:format("Generated ~ts.app~n", [Name]).
@@ -1,53 +1,20 @@
 defmodule Access do
  @moduledoc """
-  Key-based access to data structures.
+  Key-based access to data structures via the `foo[bar]` syntax.

-  Elixir supports three main key-value constructs: keywords,
-  maps, and structs. It also supports two mechanisms to access those keys:
-  by brackets (via `data[key]`) and by dot-syntax (via `data.field`).
+  Elixir provides two syntaxes for accessing values. `user[:name]`
+  is used by dynamic structures, like maps and keywords, while
+  `user.name` is used by structs. The main difference is that
+  `user[:name]` won't raise if the key `:name` is missing but
+  `user.name` will raise if there is no `:name` key.

-  In the next section we will briefly recap the key-value constructs and then
-  discuss the access mechanisms.
+  ## Key-based lookups

-  ## Key-value constructs
-
-  Elixir provides three main key-value constructs, summarized below:
-
-    * keyword lists - they are lists of two-element tuples where
-      the first element is an atom. Commonly written in the
-      `[key: value]` syntax, they support only atom keys. Keyword
-      lists are used almost exclusively to pass options to functions
-      and macros. They keep the user ordering and allow duplicate
-      keys. See the `Keyword` module.
-
-    * maps - they are the "go to" key-value data structure in Elixir.
-      They are capable of supporting billions of keys of any type. They are
-      written using the `%{key => value}` syntax and also support the
-      `%{key: value}` syntax when the keys are atoms. They do not
-      have any specified ordering and do not allow duplicate keys.
-      See the `Map` module.
-
-    * structs - they are named maps with a pre-determined set of keys.
-      They are defined with `defstruct/1` and written using the
-      `%StructName{key: value}` syntax.
-
-  ## Key-based accessors
-
-  Elixir provides two mechanisms to access data structures by key,
-  described next.
-
-  ### Bracket-based access
-
-  The `data[key]` syntax is used to access data structures with a
-  dynamic number of keys, such as keywords and maps. The key can
-  be of any type. The bracket-based access syntax returns `nil`
-  if the key does not exist:
+  Out of the box, Access works with `Keyword` and `Map`:

      iex> keywords = [a: 1, b: 2]
      iex> keywords[:a]
      1
-      iex> keywords[:c]
-      nil

      iex> map = %{a: 1, b: 2}
      iex> map[:a]
@@ -57,230 +24,118 @@ defmodule Access do
      iex> star_ratings[1.5]
      "★☆"

+  Access can be combined with `Kernel.put_in/3` to put a value
+  in a given key:
+
+      iex> map = %{a: 1, b: 2}
+      iex> put_in map[:a], 3
+      %{a: 3, b: 2}
+
  This syntax is very convenient as it can be nested arbitrarily:

      iex> users = %{"john" => %{age: 27}, "meg" => %{age: 23}}
-      iex> put_in(users["john"][:age], 28)
+      iex> put_in users["john"][:age], 28
      %{"john" => %{age: 28}, "meg" => %{age: 23}}

-  Furthermore, the bracket-based access syntax transparently ignores
-  `nil` values. When trying to access anything on a `nil` value, `nil`
-  is returned:
+  Furthermore, Access transparently ignores `nil` values:

      iex> keywords = [a: 1, b: 2]
      iex> keywords[:c][:unknown]
      nil

-      iex> nil[:a]
-      nil
+  Since Access is a behaviour, it can be implemented to key-value
+  data structures. The implementation should be added to the
+  module that defines the struct being access. Access requires the
+  key comparison to be implemented using the `===` operator.

-  Internally, `data[key]` translates  to `Access.get(term, key, nil)`.
-  Developers interested in implementing their own key-value data
-  structures can implement the `Access` behaviour to provide the
-  bracket-based access syntax. `Access` requires the key comparison
-  to be implemented using the `===/2` operator.
+  ## Field-based lookups

-  ### Dot-based syntax
+  The Access syntax (`foo[bar]`) cannot be used to access fields in
+  structs. That's by design, as Access is meant to be used for
+  dynamic key-value structures, like maps and keywords, and not
+  by static ones like structs.

-  The `data.field` syntax is used exclusively to access atom fields
-  in maps and structs. If the accessed field does not exist, an error is
-  raised. This is a deliberate decision: since all of the
-  fields in a struct are pre-determined, structs support only the
-  dot-based syntax and not the access one.
+  However Elixir already provides a field-based lookup for structs.
+  Imagine a struct named `User` with name and age fields. The
+  following would raise:

-  Imagine a struct named `User` with a `:name` field. The following would raise:
-
-      user = %User{name: "John"}
+      user = %User{name: "john"}
      user[:name]
-      # ** (UndefinedFunctionError) undefined function User.fetch/2 (User does not implement the Access behaviour)
+      ** (UndefinedFunctionError) undefined function User.fetch/2
+         (User does not implement the Access behaviour)

-  Instead we should use the `user.name` syntax to access fields:
+  Structs instead use the `user.name` syntax:

      user.name
-      #=> "John"
+      #=> "john"

-  Differently from `user[:name]`, `user.name` is not extensible via
-  a behaviour and is restricted only to structs and atom keys in maps.
+  The same `user.name` syntax can also be used by `Kernel.put_in/2`
+  to for updating structs fields:

-  ### Summing up
+      put_in user.name, "mary"
+      %User{name: "mary"}

-  The bracket-based syntax, `user[:name]`, is used by dynamic structures,
-  is extensible and returns nil on misisng keys.
+  Differently from `user[:name]`, `user.name` cannot be extended by
+  the developers, and will be always restricted to only maps and
+  structs.

-  The dot-based syntax, `user.name`, is used exclusively to access atom
-  keys in maps and structs, and it raises on missing keys.
+  Summing up:

-  ## Nested data structures
+    * `user[:name]` is used by dynamic structures, is extensible and
+      does not raise on missing keys
+    * `user.name` is used by static structures, it is not extensible
+      and it will raise on missing keys

-  Both key-based access syntaxes can be used with the nested update
-  functions and macros in `Kernel`, such as `Kernel.get_in/2`, `Kernel.put_in/3`,
-  `Kernel.update_in/3`, `Kernel.pop_in/2`, and `Kernel.get_and_update_in/3`.
-
-  For example, to update a map inside another map:
-
-     iex> users = %{"john" => %{age: 27}, "meg" => %{age: 23}}
-     iex> put_in(users["john"].age, 28)
-     %{"john" => %{age: 28}, "meg" => %{age: 23}}
-
-  This module provides convenience functions for traversing other
-  structures, like tuples and lists. These functions can be used
-  in all the `Access`-related functions and macros in `Kernel`.
-
-  For instance, given a user map with the `:name` and `:languages` keys,
-  here is how to deeply traverse the map and convert all language names
-  to uppercase:
-
-      iex> languages = [
-      ...>   %{name: "elixir", type: :functional},
-      ...>   %{name: "c", type: :procedural},
-      ...> ]
-      iex> user = %{name: "john", languages: languages}
-      iex> update_in(user, [:languages, Access.all(), :name], &String.upcase/1)
-      %{name: "john",
-        languages: [%{name: "ELIXIR", type: :functional},
-                    %{name: "C", type: :procedural}]}
-
-  See the functions `key/1`, `key!/1`, `elem/1`, and `all/0` for some of the
-  available accessors.
  """

-  @type container :: keyword | struct | map
-  @type nil_container :: nil
-  @type any_container :: any
-  @type t :: container | nil_container | any_container
+  @type t :: list | map | nil
  @type key :: any
  @type value :: any

-  @type get_fun(data, get_value) ::
-          (:get, data, (term -> term) ->
-             {get_value, new_data :: container})
+  @callback fetch(t, key) :: {:ok, value} | :error
+  @callback get_and_update(t, key, (value -> {value, value})) :: {value, t}

-  @type get_and_update_fun(data, get_value) ::
-          (:get_and_update, data, (term -> term) ->
-             {get_value, new_data :: container} | :pop)
-
-  @type access_fun(data, get_value) ::
-          get_fun(data, get_value) | get_and_update_fun(data, get_value)
-
-  @doc """
-  Invoked in order to access the value stored under `key` in the given term `term`.
-
-  This function should return `{:ok, value}` where `value` is the value under
-  `key` if the key exists in the term, or `:error` if the key does not exist in
-  the term.
-
-  Many of the functions defined in the `Access` module internally call this
-  function. This function is also used when the square-brackets access syntax
-  (`structure[key]`) is used: the `fetch/2` callback implemented by the module
-  that defines the `structure` struct is invoked and if it returns `{:ok,
-  value}` then `value` is returned, or if it returns `:error` then `nil` is
-  returned.
-
-  See the `Map.fetch/2` and `Keyword.fetch/2` implementations for examples of
-  how to implement this callback.
-  """
-  @callback fetch(term :: t, key) :: {:ok, value} | :error
-
-  @doc """
-  Invoked in order to access the value under `key` and update it at the same time.
-
-  The implementation of this callback should invoke `fun` with the value under
-  `key` in the passed structure `data`, or with `nil` if `key` is not present in it.
-  This function must return either `{get_value, update_value}` or `:pop`.
-
-  If the passed function returns `{get_value, update_value}`,
-  the return value of this callback should be `{get_value, new_data}`, where:
-
-    * `get_value` is the retrieved value (which can be operated on before being returned)
-
-    * `update_value` is the new value to be stored under `key`
-
-    * `new_data` is `data` after updating the value of `key` with `update_value`.
-
-  If the passed function returns `:pop`, the return value of this callback
-  must be `{value, new_data}` where `value` is the value under `key`
-  (or `nil` if not present) and `new_data` is `data` without `key`.
-
-  See the implementations of `Map.get_and_update/3` or `Keyword.get_and_update/3`
-  for more examples.
-  """
-  @callback get_and_update(data, key, (value -> {get_value, value} | :pop)) :: {get_value, data}
-            when get_value: var, data: container | any_container
-
-  @doc """
-  Invoked to "pop" the value under `key` out of the given data structure.
-
-  When `key` exists in the given structure `data`, the implementation should
-  return a `{value, new_data}` tuple where `value` is the value that was under
-  `key` and `new_data` is `term` without `key`.
-
-  When `key` is not present in the given structure, a tuple `{value, data}`
-  should be returned, where `value` is implementation-defined.
-
-  See the implementations for `Map.pop/3` or `Keyword.pop/3` for more examples.
-  """
-  @callback pop(data, key) :: {value, data} when data: container | any_container
-
-  defmacrop raise_undefined_behaviour(exception, module, top) do
+  defmacrop raise_undefined_behaviour(e, struct, top) do
    quote do
-      exception =
-        case __STACKTRACE__ do
-          [unquote(top) | _] ->
-            reason = "#{inspect(unquote(module))} does not implement the Access behaviour"
-            %{unquote(exception) | reason: reason}
-
+      stacktrace = System.stacktrace
+      e =
+        case stacktrace do
+          [unquote(top)|_] ->
+            %{unquote(e) | reason: "#{inspect unquote(struct)} does not implement the Access behaviour"}
          _ ->
-            unquote(exception)
+            unquote(e)
        end
-
-      reraise exception, __STACKTRACE__
+      reraise e, stacktrace
    end
  end

  @doc """
-  Fetches the value for the given key in a container (a map, keyword
-  list, or struct that implements the `Access` behaviour).
-
-  Returns `{:ok, value}` where `value` is the value under `key` if there is such
-  a key, or `:error` if `key` is not found.
-
-  ## Examples
-
-      iex> Access.fetch(%{name: "meg", age: 26}, :name)
-      {:ok, "meg"}
-
-      iex> Access.fetch([ordered: true, on_timeout: :exit], :timeout)
-      :error
-
+  Fetches the container's value for the given key.
  """
-  @spec fetch(container, term) :: {:ok, term} | :error
-  @spec fetch(nil_container, any) :: :error
+  @spec fetch(t, term) :: {:ok, term} | :error
  def fetch(container, key)

-  def fetch(%module{} = container, key) do
-    module.fetch(container, key)
+  def fetch(%{__struct__: struct} = container, key) do
+    struct.fetch(container, key)
  rescue
-    exception in UndefinedFunctionError ->
-      raise_undefined_behaviour(exception, module, {^module, :fetch, [^container, ^key], _})
+    e in UndefinedFunctionError ->
+      raise_undefined_behaviour e, struct, {^struct, :fetch, [^container, ^key], _}
  end

-  def fetch(map, key) when is_map(map) do
-    case map do
-      %{^key => value} -> {:ok, value}
-      _ -> :error
-    end
+  def fetch(%{} = map, key) do
+    :maps.find(key, map)
  end

  def fetch(list, key) when is_list(list) and is_atom(key) do
    case :lists.keyfind(key, 1, list) do
-      {_, value} -> {:ok, value}
+      {^key, value} -> {:ok, value}
      false -> :error
    end
  end

  def fetch(list, key) when is_list(list) do
    raise ArgumentError,
-          "the Access calls for keywords expect the key to be an atom, got: " <> inspect(key)
+      "the Access calls for keywords expect the key to be an atom, got: " <> inspect(key)
  end

  def fetch(nil, _key) do
@@ -288,97 +143,45 @@ defmodule Access do
  end

  @doc """
-  Gets the value for the given key in a container (a map, keyword
-  list, or struct that implements the `Access` behaviour).
-
-  Returns the value under `key` if there is such a key, or `default` if `key` is
-  not found.
-
-  ## Examples
-
-      iex> Access.get(%{name: "john"}, :name, "default name")
-      "john"
-      iex> Access.get(%{name: "john"}, :age, 25)
-      25
-
-      iex> Access.get([ordered: true], :timeout)
-      nil
-
+  Gets the container's value for the given key.
  """
-  @spec get(container, term, term) :: term
-  @spec get(nil_container, any, default) :: default when default: var
-  def get(container, key, default \\ nil)
-
-  # Reimplementing the same logic as Access.fetch/2 here is done for performance, since
-  # this is called a lot and calling fetch/2 means introducing some overhead (like
-  # building the "{:ok, _}" tuple and deconstructing it back right away).
-
-  def get(%module{} = container, key, default) do
-    try do
-      module.fetch(container, key)
-    rescue
-      exception in UndefinedFunctionError ->
-        raise_undefined_behaviour(exception, module, {^module, :fetch, [^container, ^key], _})
-    else
+  @spec get(t, term, term) :: term
+  def get(container, key, default \\ nil) do
+    case fetch(container, key) do
      {:ok, value} -> value
      :error -> default
    end
  end

-  def get(map, key, default) when is_map(map) do
-    case map do
-      %{^key => value} -> value
-      _ -> default
-    end
-  end
-
-  def get(list, key, default) when is_list(list) and is_atom(key) do
-    case :lists.keyfind(key, 1, list) do
-      {_, value} -> value
-      false -> default
-    end
-  end
-
-  def get(list, key, _default) when is_list(list) do
-    raise ArgumentError,
-          "the Access calls for keywords expect the key to be an atom, got: " <> inspect(key)
-  end
-
-  def get(nil, _key, default) do
-    default
-  end
-
  @doc """
-  Gets and updates the given key in a `container` (a map, a keyword list,
-  a struct that implements the `Access` behaviour).
+  Gets and updates the container's value for the given key, in a single pass.

-  The `fun` argument receives the value of `key` (or `nil` if `key` is not
-  present in `container`) and must return a two-element tuple `{get_value, update_value}`:
-  the "get" value `get_value` (the retrieved value, which can be operated on before
-  being returned) and the new value to be stored under `key` (`update_value`).
-  `fun` may also return `:pop`, which means the current value
-  should be removed from the container and returned.
+  The argument function `fun` must receive the value for the given `key` (or
+  `nil` if the key doesn't exist in `container`). It must return a tuple
+  containing the `get` value and the new value to be stored in the `container`.

-  The returned value is a two-element tuple with the "get" value returned by
-  `fun` and a new container with the updated value under `key`.
+  This function returns a two-element tuple.
+  The first element is the `get` value, as returned by `fun`.
+  The second element is the container, updated with the value returned by `fun`.
  """
-  @spec get_and_update(data, key, (value -> {get_value, value} | :pop)) :: {get_value, data}
-        when get_value: var, data: container
+  @spec get_and_update(t, term, (term -> {get, term})) :: {get, t} when get: var
  def get_and_update(container, key, fun)

-  def get_and_update(%module{} = container, key, fun) do
-    module.get_and_update(container, key, fun)
+  def get_and_update(%{__struct__: struct} = container, key, fun) do
+    struct.get_and_update(container, key, fun)
  rescue
-    exception in UndefinedFunctionError ->
-      raise_undefined_behaviour(
-        exception,
-        module,
-        {^module, :get_and_update, [^container, ^key, ^fun], _}
-      )
+    e in UndefinedFunctionError ->
+      raise_undefined_behaviour e, struct, {^struct, :get_and_update, [^container, ^key, ^fun], _}
  end

-  def get_and_update(map, key, fun) when is_map(map) do
-    Map.get_and_update(map, key, fun)
+  def get_and_update(%{} = map, key, fun) do
+    current_value = case :maps.find(key, map) do
+      {:ok, value} -> value
+      :error -> nil
+    end
+
+    {get, update} = fun.(current_value)
+    {get, :maps.put(key, update, map)}
  end

  def get_and_update(list, key, fun) when is_list(list) do
@@ -386,427 +189,7 @@ defmodule Access do
  end

  def get_and_update(nil, key, _fun) do
-    raise ArgumentError, "could not put/update key #{inspect(key)} on a nil value"
-  end
-
-  @doc """
-  Removes the entry with a given key from a container (a map, keyword
-  list, or struct that implements the `Access` behaviour).
-
-  Returns a tuple containing the value associated with the key and the
-  updated container. `nil` is returned for the value if the key isn't
-  in the container.
-
-  ## Examples
-
-  With a map:
-
-      iex> Access.pop(%{name: "Elixir", creator: "Valim"}, :name)
-      {"Elixir", %{creator: "Valim"}}
-
-  A keyword list:
-
-      iex> Access.pop([name: "Elixir", creator: "Valim"], :name)
-      {"Elixir", [creator: "Valim"]}
-
-  An unknown key:
-
-      iex> Access.pop(%{name: "Elixir", creator: "Valim"}, :year)
-      {nil, %{creator: "Valim", name: "Elixir"}}
-
-  """
-  @spec pop(data, key) :: {value, data} when data: container
-  def pop(%module{} = container, key) do
-    module.pop(container, key)
-  rescue
-    exception in UndefinedFunctionError ->
-      raise_undefined_behaviour(exception, module, {^module, :pop, [^container, ^key], _})
-  end
-
-  def pop(map, key) when is_map(map) do
-    Map.pop(map, key)
-  end
-
-  def pop(list, key) when is_list(list) do
-    Keyword.pop(list, key)
-  end
-
-  def pop(nil, key) do
-    raise ArgumentError, "could not pop key #{inspect(key)} on a nil value"
-  end
-
-  ## Accessors
-
-  @doc """
-  Returns a function that accesses the given key in a map/struct.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  The returned function uses the default value if the key does not exist.
-  This can be used to specify defaults and safely traverse missing keys:
-
-      iex> get_in(%{}, [Access.key(:user, %{name: "meg"}), Access.key(:name)])
-      "meg"
-
-  Such is also useful when using update functions, allowing us to introduce
-  values as we traverse the data structure for updates:
-
-      iex> put_in(%{}, [Access.key(:user, %{}), Access.key(:name)], "Mary")
-      %{user: %{name: "Mary"}}
-
-  ## Examples
-
-      iex> map = %{user: %{name: "john"}}
-      iex> get_in(map, [Access.key(:unknown, %{}), Access.key(:name, "john")])
-      "john"
-      iex> get_and_update_in(map, [Access.key(:user), Access.key(:name)], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {"john", %{user: %{name: "JOHN"}}}
-      iex> pop_in(map, [Access.key(:user), Access.key(:name)])
-      {"john", %{user: %{}}}
-
-  An error is raised if the accessed structure is not a map or a struct:
-
-      iex> get_in(nil, [Access.key(:foo)])
-      ** (BadMapError) expected a map, got: nil
-
-      iex> get_in([], [Access.key(:foo)])
-      ** (BadMapError) expected a map, got: []
-
-  """
-  @spec key(key, term) :: access_fun(data :: struct | map, get_value :: term)
-  def key(key, default \\ nil) do
-    fn
-      :get, data, next ->
-        next.(Map.get(data, key, default))
-
-      :get_and_update, data, next ->
-        value = Map.get(data, key, default)
-
-        case next.(value) do
-          {get, update} -> {get, Map.put(data, key, update)}
-          :pop -> {value, Map.delete(data, key)}
-        end
-    end
-  end
-
-  @doc """
-  Returns a function that accesses the given key in a map/struct.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  Similar to `key/2`, but the returned function raises if the key does not exist.
-
-  ## Examples
-
-      iex> map = %{user: %{name: "john"}}
-      iex> get_in(map, [Access.key!(:user), Access.key!(:name)])
-      "john"
-      iex> get_and_update_in(map, [Access.key!(:user), Access.key!(:name)], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {"john", %{user: %{name: "JOHN"}}}
-      iex> pop_in(map, [Access.key!(:user), Access.key!(:name)])
-      {"john", %{user: %{}}}
-      iex> get_in(map, [Access.key!(:user), Access.key!(:unknown)])
-      ** (KeyError) key :unknown not found in: %{name: \"john\"}
-
-  An error is raised if the accessed structure is not a map/struct:
-
-      iex> get_in([], [Access.key!(:foo)])
-      ** (RuntimeError) Access.key!/1 expected a map/struct, got: []
-
-  """
-  @spec key!(key) :: access_fun(data :: struct | map, get_value :: term)
-  def key!(key) do
-    fn
-      :get, %{} = data, next ->
-        next.(Map.fetch!(data, key))
-
-      :get_and_update, %{} = data, next ->
-        value = Map.fetch!(data, key)
-
-        case next.(value) do
-          {get, update} -> {get, Map.put(data, key, update)}
-          :pop -> {value, Map.delete(data, key)}
-        end
-
-      _op, data, _next ->
-        raise "Access.key!/1 expected a map/struct, got: #{inspect(data)}"
-    end
-  end
-
-  @doc ~S"""
-  Returns a function that accesses the element at the given index in a tuple.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  The returned function raises if `index` is out of bounds.
-
-  Note that popping elements out of tuples is not possible and raises an
-  error.
-
-  ## Examples
-
-      iex> map = %{user: {"john", 27}}
-      iex> get_in(map, [:user, Access.elem(0)])
-      "john"
-      iex> get_and_update_in(map, [:user, Access.elem(0)], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {"john", %{user: {"JOHN", 27}}}
-      iex> pop_in(map, [:user, Access.elem(0)])
-      ** (RuntimeError) cannot pop data from a tuple
-
-  An error is raised if the accessed structure is not a tuple:
-
-      iex> get_in(%{}, [Access.elem(0)])
-      ** (RuntimeError) Access.elem/1 expected a tuple, got: %{}
-
-  """
-  @spec elem(non_neg_integer) :: access_fun(data :: tuple, get_value :: term)
-  def elem(index) when is_integer(index) and index >= 0 do
-    pos = index + 1
-
-    fn
-      :get, data, next when is_tuple(data) ->
-        next.(:erlang.element(pos, data))
-
-      :get_and_update, data, next when is_tuple(data) ->
-        value = :erlang.element(pos, data)
-
-        case next.(value) do
-          {get, update} -> {get, :erlang.setelement(pos, data, update)}
-          :pop -> raise "cannot pop data from a tuple"
-        end
-
-      _op, data, _next ->
-        raise "Access.elem/1 expected a tuple, got: #{inspect(data)}"
-    end
-  end
-
-  @doc ~S"""
-  Returns a function that accesses all the elements in a list.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  ## Examples
-
-      iex> list = [%{name: "john"}, %{name: "mary"}]
-      iex> get_in(list, [Access.all(), :name])
-      ["john", "mary"]
-      iex> get_and_update_in(list, [Access.all(), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {["john", "mary"], [%{name: "JOHN"}, %{name: "MARY"}]}
-      iex> pop_in(list, [Access.all(), :name])
-      {["john", "mary"], [%{}, %{}]}
-
-  Here is an example that traverses the list dropping even
-  numbers and multiplying odd numbers by 2:
-
-      iex> require Integer
-      iex> get_and_update_in([1, 2, 3, 4, 5], [Access.all], fn num ->
-      ...>   if Integer.is_even(num), do: :pop, else: {num, num * 2}
-      ...> end)
-      {[1, 2, 3, 4, 5], [2, 6, 10]}
-
-  An error is raised if the accessed structure is not a list:
-
-      iex> get_in(%{}, [Access.all()])
-      ** (RuntimeError) Access.all/0 expected a list, got: %{}
-
-  """
-  @spec all() :: access_fun(data :: list, get_value :: list)
-  def all() do
-    &all/3
-  end
-
-  defp all(:get, data, next) when is_list(data) do
-    Enum.map(data, next)
-  end
-
-  defp all(:get_and_update, data, next) when is_list(data) do
-    all(data, next, _gets = [], _updates = [])
-  end
-
-  defp all(_op, data, _next) do
-    raise "Access.all/0 expected a list, got: #{inspect(data)}"
-  end
-
-  defp all([head | rest], next, gets, updates) do
-    case next.(head) do
-      {get, update} -> all(rest, next, [get | gets], [update | updates])
-      :pop -> all(rest, next, [head | gets], updates)
-    end
-  end
-
-  defp all([], _next, gets, updates) do
-    {:lists.reverse(gets), :lists.reverse(updates)}
-  end
-
-  @doc ~S"""
-  Returns a function that accesses the element at `index` (zero based) of a list.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  ## Examples
-
-      iex> list = [%{name: "john"}, %{name: "mary"}]
-      iex> get_in(list, [Access.at(1), :name])
-      "mary"
-      iex> get_and_update_in(list, [Access.at(0), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {"john", [%{name: "JOHN"}, %{name: "mary"}]}
-
-  `at/1` can also be used to pop elements out of a list or
-  a key inside of a list:
-
-      iex> list = [%{name: "john"}, %{name: "mary"}]
-      iex> pop_in(list, [Access.at(0)])
-      {%{name: "john"}, [%{name: "mary"}]}
-      iex> pop_in(list, [Access.at(0), :name])
-      {"john", [%{}, %{name: "mary"}]}
-
-  When the index is out of bounds, `nil` is returned and the update function is never called:
-
-      iex> list = [%{name: "john"}, %{name: "mary"}]
-      iex> get_in(list, [Access.at(10), :name])
-      nil
-      iex> get_and_update_in(list, [Access.at(10), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {nil, [%{name: "john"}, %{name: "mary"}]}
-
-  An error is raised for negative indexes:
-
-      iex> get_in([], [Access.at(-1)])
-      ** (FunctionClauseError) no function clause matching in Access.at/1
-
-  An error is raised if the accessed structure is not a list:
-
-      iex> get_in(%{}, [Access.at(1)])
-      ** (RuntimeError) Access.at/1 expected a list, got: %{}
-
-  """
-  @spec at(non_neg_integer) :: access_fun(data :: list, get_value :: term)
-  def at(index) when is_integer(index) and index >= 0 do
-    fn op, data, next -> at(op, data, index, next) end
-  end
-
-  defp at(:get, data, index, next) when is_list(data) do
-    data |> Enum.at(index) |> next.()
-  end
-
-  defp at(:get_and_update, data, index, next) when is_list(data) do
-    get_and_update_at(data, index, next, [])
-  end
-
-  defp at(_op, data, _index, _next) do
-    raise "Access.at/1 expected a list, got: #{inspect(data)}"
-  end
-
-  defp get_and_update_at([head | rest], 0, next, updates) do
-    case next.(head) do
-      {get, update} -> {get, :lists.reverse([update | updates], rest)}
-      :pop -> {head, :lists.reverse(updates, rest)}
-    end
-  end
-
-  defp get_and_update_at([head | rest], index, next, updates) do
-    get_and_update_at(rest, index - 1, next, [head | updates])
-  end
-
-  defp get_and_update_at([], _index, _next, updates) do
-    {nil, :lists.reverse(updates)}
-  end
-
-  @doc ~S"""
-  Returns a function that accesses all elements of a list that match the provided predicate.
-
-  The returned function is typically passed as an accessor to `Kernel.get_in/2`,
-  `Kernel.get_and_update_in/3`, and friends.
-
-  ## Examples
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}]
-      iex> get_in(list, [Access.filter(&(&1.salary > 20)), :name])
-      ["francine"]
-      iex> get_and_update_in(list, [Access.filter(&(&1.salary <= 20)), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {["john"], [%{name: "JOHN", salary: 10}, %{name: "francine", salary: 30}]}
-
-  `filter/1` can also be used to pop elements out of a list or
-  a key inside of a list:
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}]
-      iex> pop_in(list, [Access.filter(&(&1.salary >= 20))])
-      {[%{name: "francine", salary: 30}], [%{name: "john", salary: 10}]}
-      iex> pop_in(list, [Access.filter(&(&1.salary >= 20)), :name])
-      {["francine"], [%{name: "john", salary: 10}, %{salary: 30}]}
-
-  When no match is found, an empty list is returned and the update function is never called
-
-      iex> list = [%{name: "john", salary: 10}, %{name: "francine", salary: 30}]
-      iex> get_in(list, [Access.filter(&(&1.salary >= 50)), :name])
-      []
-      iex> get_and_update_in(list, [Access.filter(&(&1.salary >= 50)), :name], fn prev ->
-      ...>   {prev, String.upcase(prev)}
-      ...> end)
-      {[], [%{name: "john", salary: 10}, %{name: "francine", salary: 30}]}
-
-  An error is raised if the predicate is not a function or is of the incorrect arity:
-
-      iex> get_in([], [Access.filter(5)])
-      ** (FunctionClauseError) no function clause matching in Access.filter/1
-
-  An error is raised if the accessed structure is not a list:
-
-      iex> get_in(%{}, [Access.filter(fn a -> a == 10 end)])
-      ** (RuntimeError) Access.filter/1 expected a list, got: %{}
-
-  """
-  @doc since: "1.6.0"
-  @spec filter((term -> boolean)) :: access_fun(data :: list, get_value :: list)
-  def filter(func) when is_function(func) do
-    fn op, data, next -> filter(op, data, func, next) end
-  end
-
-  defp filter(:get, data, func, next) when is_list(data) do
-    data |> Enum.filter(func) |> Enum.map(next)
-  end
-
-  defp filter(:get_and_update, data, func, next) when is_list(data) do
-    get_and_update_filter(data, func, next, [], [])
-  end
-
-  defp filter(_op, data, _func, _next) do
-    raise "Access.filter/1 expected a list, got: #{inspect(data)}"
-  end
-
-  defp get_and_update_filter([head | rest], func, next, updates, gets) do
-    if func.(head) do
-      case next.(head) do
-        {get, update} ->
-          get_and_update_filter(rest, func, next, [update | updates], [get | gets])
-
-        :pop ->
-          get_and_update_filter(rest, func, next, updates, [head | gets])
-      end
-    else
-      get_and_update_filter(rest, func, next, [head | updates], gets)
-    end
-  end
-
-  defp get_and_update_filter([], _func, _next, updates, gets) do
-    {:lists.reverse(gets), :lists.reverse(updates)}
+    raise ArgumentError,
+      "could not put/update key #{inspect key} on a nil value"
  end
 end
@@ -6,19 +6,17 @@ defmodule Agent do
  must be accessed from different processes or by the same process
  at different points in time.

-  The `Agent` module provides a basic server implementation that
+  The Agent module provides a basic server implementation that
  allows state to be retrieved and updated via a simple API.

  ## Examples

  For example, in the Mix tool that ships with Elixir, we need
  to keep a set of all tasks executed by a given project. Since
-  this set is shared, we can implement it with an agent:
+  this set is shared, we can implement it with an Agent:

      defmodule Mix.TasksServer do
-        use Agent
-
-        def start_link(_) do
+        def start_link do
          Agent.start_link(fn -> MapSet.new end, name: __MODULE__)
        end

@@ -44,11 +42,12 @@ defmodule Agent do
        end
      end

-  Agents provide a segregation between the client and server APIs (similar
-  to GenServers). In particular, the anonymous functions given to the `Agent`
-  are executed inside the agent (the server). This distinction is important
-  because you may want to avoid expensive operations inside the agent,
-  as they will effectively block the agent until the request is fulfilled.
+  Note that agents still provide a segregation between the
+  client and server APIs, as seen in GenServers. In particular,
+  all code inside the function passed to the agent is executed
+  by the agent. This distinction is important because you may
+  want to avoid expensive operations inside the agent, as it will
+  effectively block the agent until the request is fulfilled.

  Consider these two examples:

@@ -62,36 +61,16 @@ defmodule Agent do
        Agent.get(agent, &(&1)) |> do_something_expensive()
      end

-  The first function blocks the agent. The second function copies all the state
-  to the client and then executes the operation in the client. One aspect to
-  consider is whether the data is large enough to require processing in the server,
-  at least initially, or small enough to be sent to the client cheaply. Another
-  factor is whether the data needs to be processed atomically: getting the
-  state and calling `do_something_expensive(state)` outside of the agent means
-  that the agent's state can be updated in the meantime. This is specially
-  important in case of updates as computing the new state in the client rather
-  than in the server can lead to race conditions if multiple clients are trying
-  to update the same state to different values.
+  The first function blocks the agent. The second function copies
+  all the state to the client and then executes the operation in the
+  client. The difference is whether the data is large enough to require
+  processing in the server, at least initially, or small enough to be
+  sent to the client cheaply.

-  Finally note `use Agent` defines a `child_spec/1` function, allowing the
-  defined module to be put under a supervision tree. The generated
-  `child_spec/1` can be customized with the following options:
+  ## Name Registration

-    * `:id` - the child specification identifier, defaults to the current module
-    * `:start` - how to start the child process (defaults to calling `__MODULE__.start_link/1`)
-    * `:restart` - when the child should be restarted, defaults to `:permanent`
-    * `:shutdown` - how to shut down the child
-
-  For example:
-
-      use Agent, restart: :transient, shutdown: 10_000
-
-  See the `Supervisor` docs for more information.
-
-  ## Name registration
-
-  An agent is bound to the same name registration rules as GenServers.
-  Read more about it in the `GenServer` documentation.
+  An Agent is bound to the same name registration rules as GenServers.
+  Read more about it in the `GenServer` docs.

  ## A word on distributed agents

@@ -116,15 +95,14 @@ defmodule Agent do
  ## Hot code swapping

  An agent can have its code hot swapped live by simply passing a module,
-  function, and arguments tuple to the update instruction. For example, imagine
+  function, and args tuple to the update instruction. For example, imagine
  you have an agent named `:sample` and you want to convert its inner state
-  from a keyword list to a map. It can be done with the following
+  from some dict structure to a map. It can be done with the following
  instruction:

      {:update, :sample, {:advanced, {Enum, :into, [%{}]}}}

-  The agent's state will be added to the given list of arguments (`[%{}]`) as
-  the first argument.
+  The agent's state will be added to the given list as the first argument.
  """

  @typedoc "Return values of `start*` functions"
@@ -139,47 +117,13 @@ defmodule Agent do
  @typedoc "The agent state"
  @type state :: term

-  @doc """
-  Returns a specification to start an agent under a supervisor.
-
-  See `Supervisor`.
-  """
-  @doc since: "1.5.0"
-  def child_spec(arg) do
-    %{
-      id: Agent,
-      start: {Agent, :start_link, [arg]}
-    }
-  end
-
-  @doc false
-  defmacro __using__(opts) do
-    quote location: :keep, bind_quoted: [opts: opts] do
-      @doc """
-      Returns a specification to start this module under a supervisor.
-
-      See `Supervisor`.
-      """
-      def child_spec(arg) do
-        default = %{
-          id: __MODULE__,
-          start: {__MODULE__, :start_link, [arg]}
-        }
-
-        Supervisor.child_spec(default, unquote(Macro.escape(opts)))
-      end
-
-      defoverridable child_spec: 1
-    end
-  end
-
  @doc """
  Starts an agent linked to the current process with the given function.

  This is often used to start the agent as part of a supervision tree.

-  Once the agent is spawned, the given function `fun` is invoked and its return
-  value is used as the agent state. Note that `start_link/2` does not return
+  Once the agent is spawned, the given function is invoked and its return
+  value is used as the agent state. Note that `start_link` does not return
  until the given function has returned.

  ## Options
@@ -200,36 +144,26 @@ defmodule Agent do
  ## Return values

  If the server is successfully created and initialized, the function returns
-  `{:ok, pid}`, where `pid` is the PID of the server. If an agent with the
+  `{:ok, pid}`, where `pid` is the pid of the server. If an agent with the
  specified name already exists, the function returns
-  `{:error, {:already_started, pid}}` with the PID of that process.
-
-  If the given function callback fails, the function returns `{:error, reason}`.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.get(pid, fn state -> state end)
-      42
-
-      iex> {:error, {exception, _stacktrace}} = Agent.start(fn -> raise "oops" end)
-      iex> exception
-      %RuntimeError{message: "oops"}
+  `{:error, {:already_started, pid}}` with the pid of that process.

+  If the given function callback fails with `reason`, the function returns
+  `{:error, reason}`.
  """
-  @spec start_link((() -> term), GenServer.options()) :: on_start
+  @spec start_link((() -> term), GenServer.options) :: on_start
  def start_link(fun, options \\ []) when is_function(fun, 0) do
    GenServer.start_link(Agent.Server, fun, options)
  end

  @doc """
-  Starts an agent linked to the current process.
+  Starts an agent linked to the current process with the given module
+  function and arguments.

-  Same as `start_link/2` but a module, function, and arguments are expected
-  instead of an anonymous function; `fun` in `module` will be called with the
-  given arguments `args` to initialize the state.
+  Same as `start_link/2` but a module, function and args are expected
+  instead of an anonymous function.
  """
-  @spec start_link(module, atom, [any], GenServer.options()) :: on_start
+  @spec start_link(module, atom, [any], GenServer.options) :: on_start
  def start_link(module, fun, args, options \\ []) do
    GenServer.start_link(Agent.Server, {module, fun, args}, options)
  end
@@ -238,48 +172,31 @@ defmodule Agent do
  Starts an agent process without links (outside of a supervision tree).

  See `start_link/2` for more information.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start(fn -> 42 end)
-      iex> Agent.get(pid, fn state -> state end)
-      42
-
  """
-  @spec start((() -> term), GenServer.options()) :: on_start
+  @spec start((() -> term), GenServer.options) :: on_start
  def start(fun, options \\ []) when is_function(fun, 0) do
    GenServer.start(Agent.Server, fun, options)
  end

  @doc """
-  Starts an agent without links with the given module, function, and arguments.
+  Starts an agent with the given module function and arguments.

-  See `start_link/4` for more information.
+  Similar to `start/2` but a module, function and args are expected
+  instead of an anonymous function.
  """
-  @spec start(module, atom, [any], GenServer.options()) :: on_start
+  @spec start(module, atom, [any], GenServer.options) :: on_start
  def start(module, fun, args, options \\ []) do
    GenServer.start(Agent.Server, {module, fun, args}, options)
  end

  @doc """
-  Gets an agent value via the given anonymous function.
+  Gets an agent value via the given function.

  The function `fun` is sent to the `agent` which invokes the function
  passing the agent state. The result of the function invocation is
-  returned from this function.
-
-  `timeout` is an integer greater than zero which specifies how many
-  milliseconds are allowed before the agent executes the function and returns
-  the result value, or the atom `:infinity` to wait indefinitely. If no result
-  is received within the specified time, the function call fails and the caller
-  exits.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.get(pid, fn state -> state end)
-      42
+  returned.

+  A timeout can also be specified (it has a default value of 5000).
  """
  @spec get(agent, (state -> a), timeout) :: a when a: var
  def get(agent, fun, timeout \\ 5000) when is_function(fun, 1) do
@@ -289,9 +206,9 @@ defmodule Agent do
  @doc """
  Gets an agent value via the given function.

-  Same as `get/3` but a module, function, and arguments are expected
+  Same as `get/3` but a module, function and args are expected
  instead of an anonymous function. The state is added as first
-  argument to the given list of arguments.
+  argument to the given list of args.
  """
  @spec get(agent, module, atom, [term], timeout) :: any
  def get(agent, module, fun, args, timeout \\ 5000) do
@@ -299,28 +216,14 @@ defmodule Agent do
  end

  @doc """
-  Gets and updates the agent state in one operation via the given anonymous
-  function.
+  Gets and updates the agent state in one operation.

  The function `fun` is sent to the `agent` which invokes the function
  passing the agent state. The function must return a tuple with two
-  elements, the first being the value to return (that is, the "get" value)
-  and the second one being the new state of the agent.
-
-  `timeout` is an integer greater than zero which specifies how many
-  milliseconds are allowed before the agent executes the function and returns
-  the result value, or the atom `:infinity` to wait indefinitely. If no result
-  is received within the specified time, the function call fails and the caller
-  exits.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.get_and_update(pid, fn state -> {state, state + 1} end)
-      42
-      iex> Agent.get(pid, fn state -> state end)
-      43
+  elements, the first being the value to return (i.e. the `get` value)
+  and the second one is the new state.

+  A timeout can also be specified (it has a default value of 5000).
  """
  @spec get_and_update(agent, (state -> {a, state}), timeout) :: a when a: var
  def get_and_update(agent, fun, timeout \\ 5000) when is_function(fun, 1) do
@@ -328,11 +231,11 @@ defmodule Agent do
  end

  @doc """
-  Gets and updates the agent state in one operation via the given function.
+  Gets and updates the agent state in one operation.

-  Same as `get_and_update/3` but a module, function, and arguments are expected
+  Same as `get_and_update/3` but a module, function and args are expected
  instead of an anonymous function. The state is added as first
-  argument to the given list of arguments.
+  argument to the given list of args.
  """
  @spec get_and_update(agent, module, atom, [term], timeout) :: any
  def get_and_update(agent, module, fun, args, timeout \\ 5000) do
@@ -340,28 +243,13 @@ defmodule Agent do
  end

  @doc """
-  Updates the agent state via the given anonymous function.
+  Updates the agent state.

  The function `fun` is sent to the `agent` which invokes the function
-  passing the agent state. The return value of `fun` becomes the new
-  state of the agent.
+  passing the agent state. The function must return the new state.

+  A timeout can also be specified (it has a default value of 5000).
  This function always returns `:ok`.
-
-  `timeout` is an integer greater than zero which specifies how many
-  milliseconds are allowed before the agent executes the function and returns
-  the result value, or the atom `:infinity` to wait indefinitely. If no result
-  is received within the specified time, the function call fails and the caller
-  exits.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.update(pid, fn state -> state + 1 end)
-      :ok
-      iex> Agent.get(pid, fn state -> state end)
-      43
-
  """
  @spec update(agent, (state -> state), timeout) :: :ok
  def update(agent, fun, timeout \\ 5000) when is_function(fun, 1) do
@@ -369,11 +257,11 @@ defmodule Agent do
  end

  @doc """
-  Updates the agent state via the given function.
+  Updates the agent state.

-  Same as `update/3` but a module, function, and arguments are expected
+  Same as `update/3` but a module, function and args are expected
  instead of an anonymous function. The state is added as first
-  argument to the given list of arguments.
+  argument to the given list of args.
  """
  @spec update(agent, module, atom, [term], timeout) :: :ok
  def update(agent, module, fun, args, timeout \\ 5000) do
@@ -381,14 +269,13 @@ defmodule Agent do
  end

  @doc """
-  Performs a cast (*fire and forget*) operation on the agent state.
+  Performs a cast (fire and forget) operation on the agent state.

  The function `fun` is sent to the `agent` which invokes the function
-  passing the agent state. The return value of `fun` becomes the new
-  state of the agent.
+  passing the agent state. The function must return the new state.

-  Note that `cast` returns `:ok` immediately, regardless of whether `agent` (or
-  the node it should live on) exists.
+  Note that `cast` returns `:ok` immediately, regardless of whether the
+  destination node or agent exists.
  """
  @spec cast(agent, (state -> state)) :: :ok
  def cast(agent, fun) when is_function(fun, 1) do
@@ -396,11 +283,11 @@ defmodule Agent do
  end

  @doc """
-  Performs a cast (*fire and forget*) operation on the agent state.
+  Performs a cast (fire and forget) operation on the agent state.

-  Same as `cast/2` but a module, function, and arguments are expected
+  Same as `cast/2` but a module, function and args are expected
  instead of an anonymous function. The state is added as first
-  argument to the given list of arguments.
+  argument to the given list of args.
  """
  @spec cast(agent, module, atom, [term]) :: :ok
  def cast(agent, module, fun, args) do
@@ -408,25 +295,25 @@ defmodule Agent do
  end

  @doc """
-  Synchronously stops the agent with the given `reason`.
+  Stops the agent with the given `reason`.

-  It returns `:ok` if the agent terminates with the given
-  reason. If the agent terminates with another reason, the call will
+  It returns `:ok` if the server terminates with the given
+  reason, if it terminates with another reason, the call will
  exit.

  This function keeps OTP semantics regarding error reporting.
  If the reason is any other than `:normal`, `:shutdown` or
  `{:shutdown, _}`, an error report will be logged.
-
-  ## Examples
-
-      iex> {:ok, pid} = Agent.start_link(fn -> 42 end)
-      iex> Agent.stop(pid)
-      :ok
-
  """
  @spec stop(agent, reason :: term, timeout) :: :ok
  def stop(agent, reason \\ :normal, timeout \\ :infinity) do
-    GenServer.stop(agent, reason, timeout)
+    if is_integer(reason) or reason == :infinity do
+      IO.write :stderr, "warning: Agent.stop(agent, timeout) is deprecated, " <>
+                        "please use Agent.stop(agent, :normal, timeout) instead\n" <>
+                        Exception.format_stacktrace
+      :gen.stop(agent, :normal, reason)
+    else
+      :gen.stop(agent, reason, timeout)
+    end
  end
 end
@@ -15,7 +15,7 @@ defmodule Agent.Server do
  def handle_call({:get_and_update, fun}, _from, state) do
    case run(fun, [state]) do
      {reply, state} -> {:reply, reply, state}
-      other -> {:stop, {:bad_return_value, other}, state}
+      other          -> {:stop, {:bad_return_value, other}, state}
    end
  end

@@ -23,10 +23,18 @@ defmodule Agent.Server do
    {:reply, :ok, run(fun, [state])}
  end

+  def handle_call(msg, from, state) do
+    super(msg, from, state)
+  end
+
  def handle_cast({:cast, fun}, state) do
    {:noreply, run(fun, [state])}
  end

+  def handle_cast(msg, state) do
+    super(msg, state)
+  end
+
  def code_change(_old, state, fun) do
    {:ok, run(fun, [state])}
  end
@@ -37,8 +45,8 @@ defmodule Agent.Server do
  end

  defp get_initial_call(fun) when is_function(fun, 0) do
-    {:module, module} = Function.info(fun, :module)
-    {:name, name} = Function.info(fun, :name)
+    {:module, module} = :erlang.fun_info(fun, :module)
+    {:name, name} = :erlang.fun_info(fun, :name)
    {module, name, 0}
  end

@@ -2,353 +2,122 @@ defmodule Application do
  @moduledoc """
  A module for working with applications and defining application callbacks.

-  Applications are the idiomatic way to package software in Erlang/OTP. To get
-  the idea, they are similar to the "library" concept common in other
-  programming languages, but with some additional characteristics.
+  In Elixir (actually, in Erlang/OTP), an application is a component
+  implementing some specific functionality, that can be started and stopped
+  as a unit, and which can be re-used in other systems.

-  An application is a component implementing some specific functionality, with a
-  standardized directory structure, configuration, and lifecycle. Applications
-  are *loaded*, *started*, and *stopped*.
+  Applications are defined with an application file named `APP.app` where
+  `APP` is the application name, usually in `underscore_case`. The application
+  file must reside in the same `ebin` directory as the compiled modules of the
+  application.

-  ## The application resource file
+  In Elixir, Mix is responsible for compiling your source code and
+  generating your application `.app` file. Furthermore, Mix is also
+  responsible for configuring, starting and stopping your application
+  and its dependencies. For this reason, this documentation will focus
+  on the remaining aspects of your application: the application environment
+  and the application callback module.

-  Applications are specified in their [*resource
-  file*](http://erlang.org/doc/man/app.html), which is a file called `APP.app`,
-  where `APP` is the application name. For example, the application resource
-  file of the OTP application `ex_unit` is called `ex_unit.app`.
+  You can learn more about Mix generation of `.app` files by typing
+  `mix help compile.app`.

-  You'll find the resource file of an application in its `ebin` directory, it is
-  generated automatically by Mix. Some of its keys are taken from the keyword
-  lists returned by the `project/0` and `application/0` functions defined in
-  `mix.exs`, and others are generated by Mix itself.
+  ## Application environment

-  You can learn more about the generation of application resource files in the
-  documentation of `Mix.Tasks.Compile.App`, available as well by running `mix
-  help compile.app`.
+  Once an application is started, OTP provides an application environment
+  that can be used to configure the application.

-  ## The application environment
-
-  The key `env` of an application resource file has a list of tuples that map
-  atoms to terms, and its contents are known as the application *environment*.
-  Note that this environment is unrelated to the operating system environment.
-
-  By default, the environment of an application is an empty list. In a Mix
-  project you can set that key in `application/0`:
+  Assuming you are inside a Mix project, you can edit the `application`
+  function in the `mix.exs` file to the following:

      def application do
-        [env: [redis_host: "localhost"]]
+        [env: [hello: :world]]
      end

-  and the generated application resource file is going to have it included.
+  In the application function, we can define the default environment values
+  for our application. By starting your application with `iex -S mix`, you
+  can access the default value:

-  The environment is available after loading the application, which is a process
-  explained later:
+      Application.get_env(:APP_NAME, :hello)
+      #=> :world

-      Application.load(:APP_NAME)
-      #=> :ok
+  It is also possible to put and delete values from the application value,
+  including new values that are not defined in the environment file (although
+  this should be avoided).

-      Application.get_env(:APP_NAME, :redis_host)
-      #=> "localhost"
+  Keep in mind that each application is responsible for its environment.
+  Do not use the functions in this module for directly accessing or modifying
+  the environment of other applications (as it may lead to inconsistent
+  data in the application environment).

-  In Mix projects, the environment of the application and its dependencies can
-  be overridden via the `config/config.exs` file. If you start the application
-  with Mix, that configuration is available at compile time, and at runtime too,
-  but take into account it is not included in the generated application resource
-  file, and it is not available if you start the application without Mix.
+  ## Application module callback

-  For example, someone using your application can override its `:redis_host`
-  environment variable as follows:
-
-      config :APP_NAME, redis_host: "redis.local"
-
-  The function `put_env/3` allows dynamic configuration of the application
-  environment, but as a rule of thumb each application is responsible for its
-  own environment. Please do not use the functions in this module for directly
-  accessing or modifying the environment of other applications.
-
-  The application environment can be overriden via the `-config` option of
-  `erl`, as well as command-line flags, as we are going to see below.
-
-  ## The application callback module
-
-  The `mod` key of an application resource file configures an application
-  callback module and start argument:
+  Often times, an application defines a supervision tree that must be started
+  and stopped when the application starts and stops. For such, we need to
+  define an application module callback. The first step is to define the
+  module callback in the application definition in the `mix.exs` file:

      def application do
        [mod: {MyApp, []}]
      end

-  This key is optional, only needed for applications that start a supervision tree.
-
-  The `MyApp` module given to `:mod` needs to implement the `Application` behaviour.
-  This can be done by putting `use Application` in that module and implementing the
-  `c:start/2` callback, for example:
+  Our application now requires the `MyApp` module to provide an application
+  callback. This can be done by invoking `use Application` in that module and
+  defining a `start/2` callback, for example:

      defmodule MyApp do
        use Application

        def start(_type, _args) do
-          children = []
-          Supervisor.start_link(children, strategy: :one_for_one)
+          MyApp.Supervisor.start_link()
        end
      end

-  The `c:start/2` callback has to spawn and link a supervisor and return `{:ok,
-  pid}` or `{:ok, pid, state}`, where `pid` is the PID of the supervisor, and
-  `state` is an optional application state. `args` is the second element of the
-  tuple given to the `:mod` option.
+  `start/2` typically returns `{:ok, pid}` or `{:ok, pid, state}` where
+  `pid` identifies the supervision tree and `state` is the application state.
+  `args` is the second element of the tuple given to the `:mod` option.

-  The `type` argument passed to `c:start/2` is usually `:normal` unless in a
+  The `type` argument passed to `start/2` is usually `:normal` unless in a
  distributed setup where application takeovers and failovers are configured.
-  Distributed applications are beyond the scope of this documentation.
+  This particular aspect of applications is explained in more detail in the
+  OTP documentation:

-  When an application is shutting down, its `c:stop/1` callback is called after
-  the supervision tree has been stopped by the runtime. This callback allows the
-  application to do any final cleanup. The argument is the state returned by
-  `c:start/2`, if it did, or `[]` otherwise. The return value of `c:stop/1` is
-  ignored.
+    * [`:application` module](http://www.erlang.org/doc/man/application.html)
+    * [Applications – OTP Design Principles](http://www.erlang.org/doc/design_principles/applications.html)

-  By using `Application`, modules get a default implementation of `c:stop/1`
-  that ignores its argument and returns `:ok`, but it can be overridden.
-
-  Application callback modules may also implement the optional callback
-  `c:prep_stop/1`. If present, `c:prep_stop/1` is invoked before the supervision
-  tree is terminated. Its argument is the state returned by `c:start/2`, if it did,
-  or `[]` otherwise, and its return value is passed to `c:stop/1`.
-
-  ## The application lifecycle
-
-  ### Loading applications
-
-  Applications are *loaded*, which means that the runtime finds and processes
-  their resource files:
-
-      Application.load(:ex_unit)
-      #=> :ok
-
-  If an application has included applications, they are also loaded. And the
-  procedure recurses if they in turn have included applications. Included
-  applications are unrelated to applications in Mix umbrella projects, they are
-  an Erlang/OTP concept that has to do with coordinated starts.
-
-  When an application is loaded, the environment specified in its resource file
-  is merged with any overrides from config files passed to `erl` via the
-  `-config` option. It is worth highlighting that releases pass `sys.config`
-  this way. The resulting environment can still be overridden again via specific
-  `-Application` flags passed to `erl`.
-
-  Loading an application *does not* load its modules.
-
-  In practice, you rarely load applications by hand because that is part of the
-  start process, explained next.
-
-  ### Starting applications
-
-  Applications are also *started*:
-
-      Application.start(:ex_unit)
-      #=> :ok
-
-  Once your application is compiled, running your system is a matter of starting
-  your current application and its dependencies. Differently from other languages,
-  Elixir does not have a `main` procedure that is responsible for starting your
-  system. Instead, you start one or more applications, each with their own
-  initialization and termination logic.
-
-  When an application is started, the runtime loads it if it hasn't been loaded
-  yet (in the technical sense described above). Then, it checks if the
-  dependencies listed in the `applications` key of the resource file are already
-  started. Having at least one dependency not started is an error condition, but
-  when you start an application with `mix run`, Mix takes care of starting all
-  the dependencies for you, so in practice you don't need to worry about it
-  unless you are starting applications manually with the API provided by this
-  module.
-
-  If the application does not have a callback module configured, starting is
-  done at this point. Otherwise, its `c:start/2` callback if invoked. The PID of
-  the top-level supervisor returned by this function is stored by the runtime
-  for later use, and the returned application state is saved too, if any.
-
-  ### Stopping applications
-
-  Started applications are, finally, *stopped*:
-
-      Application.stop(:ex_unit)
-      #=> :ok
-
-  Stopping an application without a callback module is defined, but except for
-  some system tracing, it is in practice a no-op.
-
-  Stopping an application with a callback module has three steps:
-
-  1. If present, invoke the optional callback `c:prep_stop/1`.
-  2. Terminate the top-level supervisor.
-  3. Invoke the required callback `c:stop/1`.
-
-  The arguments passed to the callbacks are related to the state optionally
-  returned by `c:start/2`, and are documented in the section about the callback
-  module above.
-
-  It is important to highlight that step 2 is a blocking one. Termination of a
-  supervisor triggers a recursive chain of children terminations, therefore
-  orderly shutting down all descendant processes. The `c:stop/1` callback is
-  invoked only after termination of the whole supervision tree.
-
-  Shutting down a live system cleanly can be done by calling `System.stop/1`. It
-  will shut down every application in the opposite order they had been started.
-
-  From Erlang/OTP 19.1, a SIGTERM from the operating system will automatically
-  translate to `System.stop/0`. Erlang/OTP 20 gives user more explicit control
-  over OS signals via the `:os.set_signal/2` function.
-
-  ## Tooling
-
-  The Mix build tool can also be used to start your applications. For example,
-  `mix test` automatically starts your application dependencies and your application
-  itself before your test runs. `mix run --no-halt` boots your current project and
-  can be used to start a long running system. See `mix help run`.
-
-  Developers can also use tools like [Distillery](https://github.com/bitwalker/distillery)
-  that build **releases**. Releases are able to package all of your source code
-  as well as the Erlang VM into a single directory. Releases also give you explicit
-  control over how each application is started and in which order. They also provide
-  a more streamlined mechanism for starting and stopping systems, debugging, logging,
-  as well as system monitoring.
-
-  Finally, Elixir provides tools such as escripts and archives, which are
-  different mechanisms for packaging your application. Those are typically used
-  when tools must be shared between developers and not as deployment options.
-  See `mix help archive.build` and `mix help escript.build` for more detail.
-
-  ## Further information
-
-  For further details on applications please check the documentation of the
-  [`application`](http://www.erlang.org/doc/man/application.html) Erlang module,
-  and the
-  [Applications](http://www.erlang.org/doc/design_principles/applications.html)
-  section of the [OTP Design Principles User's
-  Guide](http://erlang.org/doc/design_principles/users_guide.html).
+  A developer may also implement the `stop/1` callback (automatically defined
+  by `use Application`) which does any application cleanup. It receives the
+  application state and can return any value. Note that shutting down the
+  supervisor is automatically handled by the VM.
  """

-  @doc """
-  Called when an application is started.
-
-  This function is called when an application is started using
-  `Application.start/2` (and functions on top of that, such as
-  `Application.ensure_started/2`). This function should start the top-level
-  process of the application (which should be the top supervisor of the
-  application's supervision tree if the application follows the OTP design
-  principles around supervision).
-
-  `start_type` defines how the application is started:
-
-    * `:normal` - used if the startup is a normal startup or if the application
-      is distributed and is started on the current node because of a failover
-      from another node and the application specification key `:start_phases`
-      is `:undefined`.
-    * `{:takeover, node}` - used if the application is distributed and is
-      started on the current node because of a failover on the node `node`.
-    * `{:failover, node}` - used if the application is distributed and is
-      started on the current node because of a failover on node `node`, and the
-      application specification key `:start_phases` is not `:undefined`.
-
-  `start_args` are the arguments passed to the application in the `:mod`
-  specification key (e.g., `mod: {MyApp, [:my_args]}`).
-
-  This function should either return `{:ok, pid}` or `{:ok, pid, state}` if
-  startup is successful. `pid` should be the PID of the top supervisor. `state`
-  can be an arbitrary term, and if omitted will default to `[]`; if the
-  application is later stopped, `state` is passed to the `stop/1` callback (see
-  the documentation for the `c:stop/1` callback for more information).
-
-  `use Application` provides no default implementation for the `start/2`
-  callback.
-  """
-  @callback start(start_type, start_args :: term) ::
-              {:ok, pid}
-              | {:ok, pid, state}
-              | {:error, reason :: term}
-
-  @doc """
-  Called before stopping the application.
-
-  This function is called before the top-level supervisor is terminated. It
-  receives the state returned by `c:start/2`, if it did, or `[]` otherwise.
-  The return value is later passed to `c:stop/1`.
-  """
-  @callback prep_stop(state) :: state
-
-  @doc """
-  Called after an application has been stopped.
-
-  This function is called after an application has been stopped, i.e., after its
-  supervision tree has been stopped. It should do the opposite of what the
-  `c:start/2` callback did, and should perform any necessary cleanup. The return
-  value of this callback is ignored.
-
-  `state` is the state returned by `c:start/2`, if it did, or `[]` otherwise.
-  If the optional callback `c:prep_stop/1` is present, `state` is its return
-  value instead.
-
-  `use Application` defines a default implementation of this function which does
-  nothing and just returns `:ok`.
-  """
-  @callback stop(state) :: term
-
-  @doc """
-  Start an application in synchronous phases.
-
-  This function is called after `start/2` finishes but before
-  `Application.start/2` returns. It will be called once for every start phase
-  defined in the application's (and any included applications') specification,
-  in the order they are listed in.
-  """
-  @callback start_phase(phase :: term, start_type, phase_args :: term) ::
-              :ok | {:error, reason :: term}
-
-  @optional_callbacks start_phase: 3, prep_stop: 1
-
  @doc false
  defmacro __using__(_) do
    quote location: :keep do
-      @behaviour Application
+      @behaviour :application

      @doc false
      def stop(_state) do
        :ok
      end

-      defoverridable Application
+      defoverridable [stop: 1]
    end
  end

  @type app :: atom
  @type key :: atom
  @type value :: term
-  @type state :: term
-  @type start_type :: :normal | {:takeover, node} | {:failover, node}
-  @type restart_type :: :permanent | :transient | :temporary
+  @type start_type :: :permanent | :transient | :temporary

-  @application_keys [
-    :description,
-    :id,
-    :vsn,
-    :modules,
-    :maxP,
-    :maxT,
-    :registered,
-    :included_applications,
-    :applications,
-    :mod,
-    :start_phases
-  ]
+  @application_keys [:description, :id, :vsn, :modules, :maxP, :maxT, :registered,
+                     :included_applications, :applications, :mod, :start_phases]

  @doc """
  Returns the spec for `app`.

  The following keys are returned:

-    * #{Enum.map_join(@application_keys, "\n  * ", &"`#{inspect(&1)}`")}
+    * #{Enum.map_join @application_keys, "\n  * ", &inspect/1}

  Note the environment is not returned as it can be accessed via
  `fetch_env/2`. Returns `nil` if the application is not loaded.
@@ -357,7 +126,7 @@ defmodule Application do
  def spec(app) do
    case :application.get_all_key(app) do
      {:ok, info} -> :lists.keydelete(:env, 1, info)
-      :undefined -> nil
+      :undefined  -> nil
    end
  end

@@ -377,7 +146,7 @@ defmodule Application do
  end

  @doc """
-  Gets the application for the given module.
+  Get the application for the given module.

  The application is located by analyzing the spec
  of all loaded applications. Returns `nil` if
@@ -404,41 +173,6 @@ defmodule Application do

  If the configuration parameter does not exist, the function returns the
  `default` value.
-
-  ## Examples
-
-  `get_env/3` is commonly used to read the configuration of your OTP applications.
-  Since Mix configurations are commonly used to configure applications, we will use
-  this as a point of illustration.
-
-  Consider a new application `:my_app`. `:my_app` contains a database engine which
-  supports a pool of databases. The database engine needs to know the configuration for
-  each of those databases, and that configuration is supplied by key-value pairs in
-  environment of `:my_app`.
-
-      config :my_app, Databases.RepoOne,
-        # A database configuration
-        ip: "localhost"
-        port: 5433
-
-      config :my_app, Databases.RepoTwo,
-        # Another database configuration (for the same OTP app)
-        ip: "localhost"
-        port: 20717
-
-      config :my_app, my_app_databases: [Databases.RepoOne, Databases.RepoTwo]
-
-  Our database engine used by `:my_app` needs to know what databases exist, and
-  what the database configurations are. The database engine can make a call to
-  `get_env(:my_app, :my_app_databases)` to retrieve the list of databases (specified
-  by module names). Our database engine can then traverse each repository in the
-  list and then call `get_env(:my_app, Databases.RepoOne)` and so forth to retrieve
-  the configuration of each one.
-
-  **Important:** if you are writing a library to be used by other developers,
-  it is generally recommended to avoid the application environment, as the
-  application environment is effectively a global storage. For more information,
-  read our [library guidelines](/library-guidelines.html).
  """
  @spec get_env(app, key, value) :: value
  def get_env(app, key, default \\ nil) do
@@ -466,27 +200,11 @@ defmodule Application do
  @spec fetch_env!(app, key) :: value | no_return
  def fetch_env!(app, key) do
    case fetch_env(app, key) do
-      {:ok, value} ->
-        value
-
+      {:ok, value} -> value
      :error ->
-        vsn = :application.get_key(app, :vsn)
-        app = inspect(app)
-        key = inspect(key)
-
-        case vsn do
-          {:ok, _} ->
-            raise ArgumentError,
-                  "could not fetch application environment #{key} for application #{app} " <>
-                    "because configuration #{key} was not set"
-
-          :undefined ->
-            raise ArgumentError,
-                  "could not fetch application environment #{key} for application #{app} " <>
-                    "because the application was not loaded/started. If your application " <>
-                    "depends on #{app} at runtime, make sure to load/start it or list it " <>
-                    "under :extra_applications in your mix.exs file"
-        end
+        raise ArgumentError,
+          "application #{inspect app} is not loaded, " <>
+          "or the configuration parameter #{inspect key} is not set"
    end
  end

@@ -495,7 +213,7 @@ defmodule Application do

  ## Options

-    * `:timeout` - the timeout for the change (defaults to `5_000` milliseconds)
+    * `:timeout`    - the timeout for the change (defaults to 5000ms)
    * `:persistent` - persists the given value on application load and reloads

  If `put_env/4` is called before the application is loaded, the application
@@ -507,7 +225,7 @@ defmodule Application do
  in the application resource file on load. This means persistent values will
  stick after the application is loaded and also on application reload.
  """
-  @spec put_env(app, key, value, timeout: timeout, persistent: boolean) :: :ok
+  @spec put_env(app, key, value, [timeout: timeout, persistent: boolean]) :: :ok
  def put_env(app, key, value, opts \\ []) do
    :application.set_env(app, key, value, opts)
  end
@@ -517,7 +235,7 @@ defmodule Application do

  See `put_env/4` for a description of the options.
  """
-  @spec delete_env(app, key, timeout: timeout, persistent: boolean) :: :ok
+  @spec delete_env(app, key, [timeout: timeout, persistent: boolean]) :: :ok
  def delete_env(app, key, opts \\ []) do
    :application.unset_env(app, key, opts)
  end
@@ -532,7 +250,7 @@ defmodule Application do
      :ok = Application.ensure_started(:my_test_dep)

  """
-  @spec ensure_started(app, restart_type) :: :ok | {:error, term}
+  @spec ensure_started(app, start_type) :: :ok | {:error, term}
  def ensure_started(app, type \\ :temporary) when is_atom(app) do
    :application.ensure_started(app, type)
  end
@@ -544,7 +262,7 @@ defmodule Application do
  `:applications` in the `.app` file in case they were not previously
  started.
  """
-  @spec ensure_all_started(app, restart_type) :: {:ok, [app]} | {:error, {app, term}}
+  @spec ensure_all_started(app, start_type) :: {:ok, [app]} | {:error, {app, term}}
  def ensure_all_started(app, type \\ :temporary) when is_atom(app) do
    :application.ensure_all_started(app, type)
  end
@@ -560,7 +278,7 @@ defmodule Application do
  started before this application is. If not, `{:error, {:not_started, app}}` is
  returned, where `app` is the name of the missing application.

-  In case you want to automatically load **and start** all of `app`'s dependencies,
+  In case you want to automatically  load **and start** all of `app`'s dependencies,
  see `ensure_all_started/2`.

  The `type` argument specifies the type of the application:
@@ -583,7 +301,7 @@ defmodule Application do
  Note also that the `:transient` type is of little practical use, since when a
  supervision tree terminates, the reason is set to `:shutdown`, not `:normal`.
  """
-  @spec start(app, restart_type) :: :ok | {:error, term}
+  @spec start(app, start_type) :: :ok | {:error, term}
  def start(app, type \\ :temporary) when is_atom(app) do
    :application.start(app, type)
  end
@@ -645,50 +363,28 @@ defmodule Application do
      #=> "bar-123"

  For more information on code paths, check the `Code` module in
-  Elixir and also Erlang's [`:code` module](http://www.erlang.org/doc/man/code.html).
+  Elixir and also Erlang's `:code` module.
  """
-  @spec app_dir(app) :: String.t()
+  @spec app_dir(app) :: String.t
  def app_dir(app) when is_atom(app) do
    case :code.lib_dir(app) do
      lib when is_list(lib) -> IO.chardata_to_string(lib)
-      {:error, :bad_name} -> raise ArgumentError, "unknown application: #{inspect(app)}"
+      {:error, :bad_name} -> raise ArgumentError, "unknown application: #{inspect app}"
    end
  end

  @doc """
  Returns the given path inside `app_dir/1`.
-
-  If `path` is a string, then it will be used as the path inside `app_dir/1`. If
-  `path` is a list of strings, it will be joined (see `Path.join/1`) and the result
-  will be used as the path inside `app_dir/1`.
-
-  ## Examples
-
-      File.mkdir_p!("foo/ebin")
-      Code.prepend_path("foo/ebin")
-
-      Application.app_dir(:foo, "my_path")
-      #=> "foo/my_path"
-
-      Application.app_dir(:foo, ["my", "nested", "path"])
-      #=> "foo/my/nested/path"
-
  """
-  @spec app_dir(app, String.t() | [String.t()]) :: String.t()
-  def app_dir(app, path)
-
+  @spec app_dir(app, String.t) :: String.t
  def app_dir(app, path) when is_binary(path) do
    Path.join(app_dir(app), path)
  end

-  def app_dir(app, path) when is_list(path) do
-    Path.join([app_dir(app) | path])
-  end
-
  @doc """
  Returns a list with information about the applications which are currently running.
  """
-  @spec started_applications(timeout) :: [{app, description :: charlist(), vsn :: charlist()}]
+  @spec started_applications(timeout) :: [tuple]
  def started_applications(timeout \\ 5000) do
    :application.which_applications(timeout)
  end
@@ -696,9 +392,9 @@ defmodule Application do
  @doc """
  Returns a list with information about the applications which have been loaded.
  """
-  @spec loaded_applications :: [{app, description :: charlist(), vsn :: charlist()}]
+  @spec loaded_applications :: [tuple]
  def loaded_applications do
-    :application.loaded_applications()
+    :application.loaded_applications
  end

  @doc """
@@ -706,12 +402,12 @@ defmodule Application do
  `ensure_started/2`, `stop/1`, `load/1` and `unload/1`,
  returns a string.
  """
-  @spec format_error(any) :: String.t()
+  @spec format_error(any) :: String.t
  def format_error(reason) do
    try do
-      do_format_error(reason)
+      impl_format_error(reason)
    catch
-      # A user could create an error that looks like a built-in one
+      # A user could create an error that looks like a builtin one
      # causing an error.
      :error, _ ->
        inspect(reason)
@@ -719,67 +415,68 @@ defmodule Application do
  end

  # exit(:normal) call is special cased, undo the special case.
-  defp do_format_error({{:EXIT, :normal}, {mod, :start, args}}) do
+  defp impl_format_error({{:EXIT, :normal}, {mod, :start, args}}) do
    Exception.format_exit({:normal, {mod, :start, args}})
  end

  # {:error, reason} return value
-  defp do_format_error({reason, {mod, :start, args}}) do
-    Exception.format_mfa(mod, :start, args) <>
-      " returned an error: " <> Exception.format_exit(reason)
+  defp impl_format_error({reason, {mod, :start, args}}) do
+    Exception.format_mfa(mod, :start, args) <> " returned an error: " <>
+      Exception.format_exit(reason)
  end

  # error or exit(reason) call, use exit reason as reason.
-  defp do_format_error({:bad_return, {{mod, :start, args}, {:EXIT, reason}}}) do
+  defp impl_format_error({:bad_return, {{mod, :start, args}, {:EXIT, reason}}}) do
    Exception.format_exit({reason, {mod, :start, args}})
  end

  # bad return value
-  defp do_format_error({:bad_return, {{mod, :start, args}, return}}) do
-    Exception.format_mfa(mod, :start, args) <> " returned a bad value: " <> inspect(return)
+  defp impl_format_error({:bad_return, {{mod, :start, args}, return}}) do
+    Exception.format_mfa(mod, :start, args) <>
+      " returned a bad value: " <> inspect(return)
  end

-  defp do_format_error({:already_started, app}) when is_atom(app) do
+  defp impl_format_error({:already_started, app}) when is_atom(app) do
    "already started application #{app}"
  end

-  defp do_format_error({:not_started, app}) when is_atom(app) do
+  defp impl_format_error({:not_started, app}) when is_atom(app) do
    "not started application #{app}"
  end

-  defp do_format_error({:bad_application, app}) do
+  defp impl_format_error({:bad_application, app}) do
    "bad application: #{inspect(app)}"
  end

-  defp do_format_error({:already_loaded, app}) when is_atom(app) do
+  defp impl_format_error({:already_loaded, app}) when is_atom(app) do
    "already loaded application #{app}"
  end

-  defp do_format_error({:not_loaded, app}) when is_atom(app) do
+  defp impl_format_error({:not_loaded, app}) when is_atom(app) do
    "not loaded application #{app}"
  end

-  defp do_format_error({:invalid_restart_type, restart}) do
+  defp impl_format_error({:invalid_restart_type, restart}) do
    "invalid application restart type: #{inspect(restart)}"
  end

-  defp do_format_error({:invalid_name, name}) do
+  defp impl_format_error({:invalid_name, name}) do
    "invalid application name: #{inspect(name)}"
  end

-  defp do_format_error({:invalid_options, opts}) do
+  defp impl_format_error({:invalid_options, opts}) do
    "invalid application options: #{inspect(opts)}"
  end

-  defp do_format_error({:badstartspec, spec}) do
+  defp impl_format_error({:badstartspec, spec}) do
    "bad application start specs: #{inspect(spec)}"
  end

-  defp do_format_error({'no such file or directory', file}) do
+  defp impl_format_error({'no such file or directory', file}) do
    "could not find application file: #{file}"
  end

-  defp do_format_error(reason) do
+  defp impl_format_error(reason) do
    Exception.format_exit(reason)
  end
 end
@@ -16,30 +16,24 @@ defmodule Atom do
      "foo"

  """
-  @spec to_string(atom) :: String.t()
+  @spec to_string(atom) :: String.t
  def to_string(atom) do
    :erlang.atom_to_binary(atom, :utf8)
  end

  @doc """
-  Converts an atom to a charlist.
+  Converts an atom to a char list.

  Inlined by the compiler.

  ## Examples

-      iex> Atom.to_charlist(:"An atom")
+      iex> Atom.to_char_list(:"An atom")
      'An atom'

  """
-  @spec to_charlist(atom) :: charlist
-  def to_charlist(atom) do
+  @spec to_char_list(atom) :: char_list
+  def to_char_list(atom) do
    :erlang.atom_to_list(atom)
  end
-
-  # TODO: Remove by 2.0
-  @doc false
-  @deprecated "Use Atom.to_charlist/1 instead"
-  @spec to_char_list(atom) :: charlist
-  def to_char_list(atom), do: Atom.to_charlist(atom)
 end
@@ -1,18 +1,14 @@
 defmodule Behaviour do
  @moduledoc """
-  Mechanism for handling behaviours.
+  This module has been deprecated.

-  This module is deprecated. Instead of `defcallback/1` and
-  `defmacrocallback/1`, the `@callback` and `@macrocallback`
-  module attributes can be used (respectively). See the
-  documentation for `Module` for more information on these
-  attributes.
-
-  Instead of `MyModule.__behaviour__(:callbacks)`,
-  `MyModule.behaviour_info(:callbacks)` can be used.
+  Instead of `defcallback`, one can simply use `@callback`.
+  Instead of `defmacrocallback`, one can simply use `@macrocallback`.
+  Instead of `__behaviour__(:callbacks)`, one can simply use `behaviour_info(:callbacks)`.
  """

-  @moduledoc deprecated: "Use @callback and @macrocallback attributes instead"
+  # TODO: Deprecate by 1.2
+  # TODO: Remove by 2.0

  @doc """
  Defines a function callback according to the given type specification.
@@ -25,7 +21,7 @@ defmodule Behaviour do
  Defines a macro callback according to the given type specification.
  """
  defmacro defmacrocallback(spec) do
-    do_defcallback(:defmacro, split_spec(spec, quote(do: Macro.t())))
+    do_defcallback(:defmacro, split_spec(spec, quote(do: Macro.t)))
  end

  defp split_spec({:when, _, [{:::, _, [spec, return]}, guard]}, _default) do
@@ -48,25 +44,21 @@ defmodule Behaviour do
    case Macro.decompose_call(spec) do
      {name, args} ->
        do_callback(kind, name, args, return, guards)
-
      _ ->
        raise ArgumentError, "invalid syntax in #{kind}callback #{Macro.to_string(spec)}"
    end
  end

  defp do_callback(kind, name, args, return, guards) do
-    fun = fn
+    :lists.foreach fn
      {:::, _, [left, right]} ->
        ensure_not_default(left)
        ensure_not_default(right)
        left
-
      other ->
        ensure_not_default(other)
        other
-    end
-
-    :lists.foreach(fun, args)
+    end, args

    spec =
      quote do
@@ -74,8 +66,8 @@ defmodule Behaviour do
      end

    case kind do
-      :def -> quote(do: @callback(unquote(spec)))
-      :defmacro -> quote(do: @macrocallback(unquote(spec)))
+      :def -> quote(do: @callback unquote(spec))
+      :defmacro -> quote(do: @macrocallback unquote(spec))
    end
  end

@@ -88,33 +80,20 @@ defmodule Behaviour do
  @doc false
  defmacro __using__(_) do
    quote do
-      warning =
-        "the Behaviour module is deprecated. Instead of using this module, " <>
-          "use the @callback and @macrocallback module attributes. See the " <>
-          "documentation for Module for more information on these attributes"
-
-      IO.warn(warning)
-
      @doc false
      def __behaviour__(:callbacks) do
        __MODULE__.behaviour_info(:callbacks)
      end

      def __behaviour__(:docs) do
-        {:docs_v1, _, :elixir, _, _, _, docs} = Code.fetch_docs(__MODULE__)
-
-        for {{kind, name, arity}, line, _, doc, _} <- docs, kind in [:callback, :macrocallback] do
+        for {tuple, line, kind, docs} <- Code.get_docs(__MODULE__, :callback_docs) do
          case kind do
-            :callback -> {{name, arity}, line, :def, __behaviour__doc_value(doc)}
-            :macrocallback -> {{name, arity}, line, :defmacro, __behaviour__doc_value(doc)}
+            :callback -> {tuple, line, :def, docs}
+            :macrocallback -> {tuple, line, :defmacro, docs}
          end
        end
      end

-      defp __behaviour__doc_value(:none), do: nil
-      defp __behaviour__doc_value(:hidden), do: false
-      defp __behaviour__doc_value(%{"en" => doc}), do: doc
-
      import unquote(__MODULE__)
    end
  end
@@ -1,38 +1,30 @@
 defmodule Bitwise do
  @moduledoc """
-  A set of macros that perform calculations on bits.
+  This module provides macro-based operators that perform calculations
+  on (sets of) bits.

-  The macros in this module come in two flavors: named or
-  operators. For example:
+  In general, you should `use` the Bitwise module as a whole:

      iex> use Bitwise
-      iex> bnot(1) # named
+      iex> bnot 1
      -2
-      iex> 1 &&& 1 # operator
+      iex> 1 &&& 1
      1

-  If you prefer to use only operators or skip them, you can
-  pass the following options:
+  When used, it accepts the following options:

-    * `:only_operators` - includes only operators
-    * `:skip_operators` - skips operators
-
-  For example:
+    * `:only_operators` - include only operators
+    * `:skip_operators` - skip operators

      iex> use Bitwise, only_operators: true
      iex> 1 &&& 1
      1

-  When invoked with no options, `use Bitwise` is equivalent
-  to `import Bitwise`.

-  All bitwise macros can be used in guards:
+  These macros can be used in guards:

      iex> use Bitwise
-      iex> odd? = fn
-      ...>   int when band(int, 1) == 1 -> true
-      ...>   _ -> false
-      ...> end
+      iex> odd? = fn(int) when band(int, 1) == 1 -> true; (_) -> false end
      iex> odd?.(1)
      true

@@ -40,17 +32,13 @@ defmodule Bitwise do

  @doc false
  defmacro __using__(options) do
-    except =
-      cond do
-        Keyword.get(options, :only_operators) ->
-          [bnot: 1, band: 2, bor: 2, bxor: 2, bsl: 2, bsr: 2]
-
-        Keyword.get(options, :skip_operators) ->
-          [~~~: 1, &&&: 2, |||: 2, ^^^: 2, <<<: 2, >>>: 2]
-
-        true ->
-          []
-      end
+    except = cond do
+      Keyword.get(options, :only_operators) ->
+        [bnot: 1, band: 2, bor: 2, bxor: 2, bsl: 2, bsr: 2]
+      Keyword.get(options, :skip_operators) ->
+        [~~~: 1, &&&: 2, |||: 2, ^^^: 2, <<<: 2, >>>: 2]
+      true -> []
+    end

    quote do
      import Bitwise, except: unquote(except)
@@ -67,7 +55,7 @@ defmodule Bitwise do

  """
  defmacro bnot(expr) do
-    quote(do: :erlang.bnot(unquote(expr)))
+    quote do: :erlang.bnot(unquote(expr))
  end

  @doc """
@@ -80,7 +68,7 @@ defmodule Bitwise do

  """
  defmacro ~~~expr do
-    quote(do: :erlang.bnot(unquote(expr)))
+    quote do: :erlang.bnot(unquote(expr))
  end

  @doc """
@@ -91,7 +79,7 @@ defmodule Bitwise do

  """
  defmacro band(left, right) do
-    quote(do: :erlang.band(unquote(left), unquote(right)))
+    quote do: :erlang.band(unquote(left), unquote(right))
  end

  @doc """
@@ -102,7 +90,7 @@ defmodule Bitwise do

  """
  defmacro left &&& right do
-    quote(do: :erlang.band(unquote(left), unquote(right)))
+    quote do: :erlang.band(unquote(left), unquote(right))
  end

  @doc """
@@ -113,7 +101,7 @@ defmodule Bitwise do

  """
  defmacro bor(left, right) do
-    quote(do: :erlang.bor(unquote(left), unquote(right)))
+    quote do: :erlang.bor(unquote(left), unquote(right))
  end

  @doc """
@@ -124,7 +112,7 @@ defmodule Bitwise do

  """
  defmacro left ||| right do
-    quote(do: :erlang.bor(unquote(left), unquote(right)))
+    quote do: :erlang.bor(unquote(left), unquote(right))
  end

  @doc """
@@ -135,7 +123,7 @@ defmodule Bitwise do

  """
  defmacro bxor(left, right) do
-    quote(do: :erlang.bxor(unquote(left), unquote(right)))
+    quote do: :erlang.bxor(unquote(left), unquote(right))
  end

  @doc """
@@ -146,7 +134,7 @@ defmodule Bitwise do

  """
  defmacro left ^^^ right do
-    quote(do: :erlang.bxor(unquote(left), unquote(right)))
+    quote do: :erlang.bxor(unquote(left), unquote(right))
  end

  @doc """
@@ -163,7 +151,7 @@ defmodule Bitwise do

  """
  defmacro bsl(left, right) do
-    quote(do: :erlang.bsl(unquote(left), unquote(right)))
+    quote do: :erlang.bsl(unquote(left), unquote(right))
  end

  @doc """
@@ -180,7 +168,7 @@ defmodule Bitwise do

  """
  defmacro left <<< right do
-    quote(do: :erlang.bsl(unquote(left), unquote(right)))
+    quote do: :erlang.bsl(unquote(left), unquote(right))
  end

  @doc """
@@ -197,7 +185,7 @@ defmodule Bitwise do

  """
  defmacro bsr(left, right) do
-    quote(do: :erlang.bsr(unquote(left), unquote(right)))
+    quote do: :erlang.bsr(unquote(left), unquote(right))
  end

  @doc """
@@ -214,6 +202,6 @@ defmodule Bitwise do

  """
  defmacro left >>> right do
-    quote(do: :erlang.bsr(unquote(left), unquote(right)))
+    quote do: :erlang.bsr(unquote(left), unquote(right))
  end
 end
@@ -1,261 +0,0 @@
-defmodule Calendar do
-  @moduledoc """
-  This module defines the responsibilities for working with
-  calendars, dates, times and datetimes in Elixir.
-
-  Currently it defines types and the minimal implementation
-  for a calendar behaviour in Elixir. The goal of the Calendar
-  features in Elixir is to provide a base for interoperability
-  instead of full-featured datetime API.
-
-  For the actual date, time and datetime structures, see `Date`,
-  `Time`, `NaiveDateTime` and `DateTime`.
-
-  Note the year, month, day, etc. designations are overspecified
-  (i.e. an integer instead of `1..12` for months) because different
-  calendars may have a different number of days per month, months per year and so on.
-  """
-
-  @type year :: integer
-  @type month :: integer
-  @type day :: integer
-  @type hour :: integer
-  @type minute :: integer
-  @type second :: integer
-
-  @typedoc """
-  The internal time format is used when converting between calendars.
-
-  It represents time as a fraction of a day (starting from midnight).
-  `parts_in_day` specifies how much of the day is already passed,
-  while `parts_per_day` signifies how many parts there fit in a day.
-  """
-  @type day_fraction :: {parts_in_day :: non_neg_integer, parts_per_day :: pos_integer}
-
-  @typedoc """
-  The internal date format that is used when converting between calendars.
-
-  This is the number of days including the fractional part that has passed of
-  the last day since 0000-01-01+00:00T00:00.00000 in ISO 8601 notation (also
-  known as midnight 1 January BC 1 of the proleptic Gregorian calendar).
-
-  The `parts_per_day` represent how many subparts the current day is subdivided in
-  (for different calendars, picking a different `parts_per_day` might make sense).
-  The `parts_in_day` represents how many of these `parts_per_day` have passed in the
-  last day.
-  """
-  @type iso_days :: {days :: integer, day_fraction}
-
-  @typedoc """
-  Microseconds with stored precision.
-
-  The precision represents the number of digits that must be used when
-  representing the microseconds to external format. If the precision is 0,
-  it means microseconds must be skipped.
-  """
-  @type microsecond :: {0..999_999, 0..6}
-
-  @typedoc "A calendar implementation"
-  @type calendar :: module
-
-  @typedoc "The time zone ID according to the IANA tz database (e.g. Europe/Zurich)"
-  @type time_zone :: String.t()
-
-  @typedoc "The time zone abbreviation (e.g. CET or CEST or BST etc.)"
-  @type zone_abbr :: String.t()
-
-  @typedoc "The time zone UTC offset in seconds"
-  @type utc_offset :: integer
-
-  @typedoc "The time zone standard offset in seconds (not zero in summer times)"
-  @type std_offset :: integer
-
-  @typedoc "Any map/struct that contains the date fields"
-  @type date :: %{optional(any) => any, calendar: calendar, year: year, month: month, day: day}
-
-  @typedoc "Any map/struct that contains the time fields"
-  @type time :: %{
-          optional(any) => any,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        }
-
-  @typedoc "Any map/struct that contains the naive_datetime fields"
-  @type naive_datetime :: %{
-          optional(any) => any,
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        }
-
-  @typedoc "Any map/struct that contains the datetime fields"
-  @type datetime :: %{
-          optional(any) => any,
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond,
-          time_zone: time_zone,
-          zone_abbr: zone_abbr,
-          utc_offset: utc_offset,
-          std_offset: std_offset
-        }
-
-  @doc """
-  Returns how many days there are in the given year-month.
-  """
-  @callback days_in_month(year, month) :: day
-
-  @doc """
-  Returns how many months there are in the given year.
-  """
-  @callback months_in_year(year) :: month
-
-  @doc """
-  Returns `true` if the given year is a leap year.
-
-  A leap year is a year of a longer length than normal. The exact meaning
-  is up to the calendar. A calendar must return `false` if it does not support
-  the concept of leap years.
-  """
-  @callback leap_year?(year) :: boolean
-
-  @doc """
-  Calculates the day of the week from the given `year`, `month`, and `day`.
-  """
-  @callback day_of_week(year, month, day) :: non_neg_integer()
-
-  @doc """
-  Converts the date into a string according to the calendar.
-  """
-  @callback date_to_string(year, month, day) :: String.t()
-
-  @doc """
-  Converts the datetime (without time zone) into a string according to the calendar.
-  """
-  @callback naive_datetime_to_string(year, month, day, hour, minute, second, microsecond) ::
-              String.t()
-
-  @doc """
-  Converts the datetime (with time zone) into a string according to the calendar.
-  """
-  @callback datetime_to_string(
-              year,
-              month,
-              day,
-              hour,
-              minute,
-              second,
-              microsecond,
-              time_zone,
-              zone_abbr,
-              utc_offset,
-              std_offset
-            ) :: String.t()
-
-  @doc """
-  Converts the time into a string according to the calendar.
-  """
-  @callback time_to_string(hour, minute, second, microsecond) :: String.t()
-
-  @doc """
-  Converts the given datetime (without time zone) into the `t:iso_days/0` format.
-  """
-  @callback naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) ::
-              iso_days
-
-  @doc """
-  Converts `t:iso_days/0` to the Calendar's datetime format.
-  """
-  @callback naive_datetime_from_iso_days(iso_days) ::
-              {year, month, day, hour, minute, second, microsecond}
-
-  @doc """
-  Converts the given time to the `t:day_fraction/0` format.
-  """
-  @callback time_to_day_fraction(hour, minute, second, microsecond) :: day_fraction
-
-  @doc """
-  Converts `t:day_fraction/0` to the Calendar's time format.
-  """
-  @callback time_from_day_fraction(day_fraction) :: {hour, minute, second, microsecond}
-
-  @doc """
-  Define the rollover moment for the given calendar.
-
-  This is the moment, in your calendar, when the current day ends
-  and the next day starts.
-
-  The result of this function is used to check if two calendars rollover at
-  the same time of day. If they do not, we can only convert datetimes and times
-  between them. If they do, this means that we can also convert dates as well
-  as naive datetimes between them.
-
-  This day fraction should be in its most simplified form possible, to make comparisons fast.
-
-  ## Examples
-
-    * If, in your Calendar, a new day starts at midnight, return {0, 1}.
-    * If, in your Calendar, a new day starts at sunrise, return {1, 4}.
-    * If, in your Calendar, a new day starts at noon, return {1, 2}.
-    * If, in your Calendar, a new day starts at sunset, return {3, 4}.
-
-  """
-  @callback day_rollover_relative_to_midnight_utc() :: day_fraction
-
-  @doc """
-  Should return `true` if the given date describes a proper date in the calendar.
-  """
-  @callback valid_date?(year, month, day) :: boolean
-
-  @doc """
-  Should return `true` if the given time describes a proper time in the calendar.
-  """
-  @callback valid_time?(hour, minute, second, microsecond) :: boolean
-
-  # General Helpers
-
-  @doc """
-  Returns `true` if two calendars have the same moment of starting a new day,
-  `false` otherwise.
-
-  If two calendars are not compatible, we can only convert datetimes and times
-  between them. If they are compatible, this means that we can also convert
-  dates as well as naive datetimes between them.
-  """
-  @doc since: "1.5.0"
-  @spec compatible_calendars?(Calendar.calendar(), Calendar.calendar()) :: boolean
-  def compatible_calendars?(calendar, calendar), do: true
-
-  def compatible_calendars?(calendar1, calendar2) do
-    calendar1.day_rollover_relative_to_midnight_utc() ==
-      calendar2.day_rollover_relative_to_midnight_utc()
-  end
-
-  @doc """
-  Returns a microsecond tuple truncated to a given precision (`:microsecond`,
-  `:millisecond` or `:second`).
-  """
-  @doc since: "1.6.0"
-  @spec truncate(Calendar.microsecond(), :microsecond | :millisecond | :second) ::
-          Calendar.microsecond()
-  def truncate(microsecond_tuple, :microsecond), do: microsecond_tuple
-
-  def truncate({microsecond, precision}, :millisecond) do
-    output_precision = min(precision, 3)
-    {div(microsecond, 1000) * 1000, output_precision}
-  end
-
-  def truncate(_, :second), do: {0, 0}
-end
@@ -1,666 +0,0 @@
-defmodule Date do
-  @moduledoc """
-  A Date struct and functions.
-
-  The Date struct contains the fields year, month, day and calendar.
-  New dates can be built with the `new/3` function or using the
-  [`~D`](`Kernel.sigil_D/2`) sigil:
-
-      iex> ~D[2000-01-01]
-      ~D[2000-01-01]
-
-  Both `new/3` and sigil return a struct where the date fields can
-  be accessed directly:
-
-      iex> date = ~D[2000-01-01]
-      iex> date.year
-      2000
-      iex> date.month
-      1
-
-  The functions on this module work with the `Date` struct as well
-  as any struct that contains the same fields as the `Date` struct,
-  such as `NaiveDateTime` and `DateTime`. Such functions expect
-  `t:Calendar.date/0` in their typespecs (instead of `t:t/0`).
-
-  Developers should avoid creating the Date structs directly
-  and instead rely on the functions provided by this module as well
-  as the ones in 3rd party calendar libraries.
-
-  ## Comparing dates
-
-  Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
-  and based on the `Date` struct fields. For proper comparison between
-  dates, use the `compare/2` function.
-
-  ## Using epochs
-
-  The `add/2` and `diff/2` functions can be used for computing dates
-  or retrieving the number of days between instants. For example, if there
-  is an interest in computing the number of days from the Unix epoch
-  (1970-01-01):
-
-      iex> Date.diff(~D[2010-04-17], ~D[1970-01-01])
-      14716
-
-      iex> Date.add(~D[1970-01-01], 14716)
-      ~D[2010-04-17]
-
-  Those functions are optimized to deal with common epochs, such
-  as the Unix Epoch above or the Gregorian Epoch (0000-01-01).
-  """
-
-  @enforce_keys [:year, :month, :day]
-  defstruct [:year, :month, :day, calendar: Calendar.ISO]
-
-  @type t :: %Date{
-          year: Calendar.year(),
-          month: Calendar.month(),
-          day: Calendar.day(),
-          calendar: Calendar.calendar()
-        }
-
-  @doc """
-  Returns a range of dates.
-
-  A range of dates represents a discrete number of dates where
-  the first and last values are dates with matching calendars.
-
-  Ranges of dates can be either increasing (`first <= last`) or
-  decreasing (`first > last`). They are also always inclusive.
-
-  ## Examples
-
-      iex> Date.range(~D[1999-01-01], ~D[2000-01-01])
-      #DateRange<~D[1999-01-01], ~D[2000-01-01]>
-
-  A range of dates implements the `Enumerable` protocol, which means
-  functions in the `Enum` module can be used to work with
-  ranges:
-
-      iex> range = Date.range(~D[2001-01-01], ~D[2002-01-01])
-      iex> Enum.count(range)
-      366
-      iex> Enum.member?(range, ~D[2001-02-01])
-      true
-      iex> Enum.reduce(range, 0, fn _date, acc -> acc - 1 end)
-      -366
-
-  """
-  @doc since: "1.5.0"
-  @spec range(Date.t(), Date.t()) :: Date.Range.t()
-  def range(%Date{calendar: calendar} = first, %Date{calendar: calendar} = last) do
-    {first_days, _} = to_iso_days(first)
-    {last_days, _} = to_iso_days(last)
-
-    %Date.Range{
-      first: first,
-      last: last,
-      first_in_iso_days: first_days,
-      last_in_iso_days: last_days
-    }
-  end
-
-  def range(%Date{}, %Date{}) do
-    raise ArgumentError, "both dates must have matching calendars"
-  end
-
-  @doc """
-  Returns the current date in UTC.
-
-  ## Examples
-
-      iex> date = Date.utc_today()
-      iex> date.year >= 2016
-      true
-
-  """
-  @doc since: "1.4.0"
-  @spec utc_today(Calendar.calendar()) :: t
-  def utc_today(calendar \\ Calendar.ISO)
-
-  def utc_today(Calendar.ISO) do
-    {:ok, {year, month, day}, _, _} = Calendar.ISO.from_unix(System.os_time(), :native)
-    %Date{year: year, month: month, day: day}
-  end
-
-  def utc_today(calendar) do
-    calendar
-    |> DateTime.utc_now()
-    |> DateTime.to_date()
-  end
-
-  @doc """
-  Returns `true` if the year in the given `date` is a leap year.
-
-  ## Examples
-
-      iex> Date.leap_year?(~D[2000-01-01])
-      true
-      iex> Date.leap_year?(~D[2001-01-01])
-      false
-      iex> Date.leap_year?(~D[2004-01-01])
-      true
-      iex> Date.leap_year?(~D[1900-01-01])
-      false
-      iex> Date.leap_year?(~N[2004-01-01 01:23:45])
-      true
-
-  """
-  @doc since: "1.4.0"
-  @spec leap_year?(Calendar.date()) :: boolean()
-  def leap_year?(date)
-
-  def leap_year?(%{calendar: calendar, year: year}) do
-    calendar.leap_year?(year)
-  end
-
-  @doc """
-  Returns the number of days in the given `date` month.
-
-  ## Examples
-
-      iex> Date.days_in_month(~D[1900-01-13])
-      31
-      iex> Date.days_in_month(~D[1900-02-09])
-      28
-      iex> Date.days_in_month(~N[2000-02-20 01:23:45])
-      29
-
-  """
-  @doc since: "1.4.0"
-  @spec days_in_month(Calendar.date()) :: Calendar.day()
-  def days_in_month(date)
-
-  def days_in_month(%{calendar: calendar, year: year, month: month}) do
-    calendar.days_in_month(year, month)
-  end
-
-  @doc """
-  Returns the number of months in the given `date` year.
-
-  ## Example
-
-      iex> Date.months_in_year(~D[1900-01-13])
-      12
-
-  """
-  @doc since: "1.7.0"
-  @spec months_in_year(Calendar.date()) :: Calendar.month()
-  def months_in_year(date)
-
-  def months_in_year(%{calendar: calendar, year: year}) do
-    calendar.months_in_year(year)
-  end
-
-  @doc """
-  Builds a new ISO date.
-
-  Expects all values to be integers. Returns `{:ok, date}` if each
-  entry fits its appropriate range, returns `{:error, reason}` otherwise.
-
-  ## Examples
-
-      iex> Date.new(2000, 1, 1)
-      {:ok, ~D[2000-01-01]}
-      iex> Date.new(2000, 13, 1)
-      {:error, :invalid_date}
-      iex> Date.new(2000, 2, 29)
-      {:ok, ~D[2000-02-29]}
-
-      iex> Date.new(2000, 2, 30)
-      {:error, :invalid_date}
-      iex> Date.new(2001, 2, 29)
-      {:error, :invalid_date}
-
-  """
-  @spec new(Calendar.year(), Calendar.month(), Calendar.day(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
-  def new(year, month, day, calendar \\ Calendar.ISO) do
-    if calendar.valid_date?(year, month, day) do
-      {:ok, %Date{year: year, month: month, day: day, calendar: calendar}}
-    else
-      {:error, :invalid_date}
-    end
-  end
-
-  @doc """
-  Converts the given date to a string according to its calendar.
-
-  ### Examples
-
-      iex> Date.to_string(~D[2000-02-28])
-      "2000-02-28"
-      iex> Date.to_string(~N[2000-02-28 01:23:45])
-      "2000-02-28"
-      iex> Date.to_string(~D[-0100-12-15])
-      "-0100-12-15"
-
-  """
-  @spec to_string(Calendar.date()) :: String.t()
-  def to_string(date)
-
-  def to_string(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.date_to_string(year, month, day)
-  end
-
-  @doc """
-  Parses the extended "Dates" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  ## Examples
-
-      iex> Date.from_iso8601("2015-01-23")
-      {:ok, ~D[2015-01-23]}
-
-      iex> Date.from_iso8601("2015:01:23")
-      {:error, :invalid_format}
-
-      iex> Date.from_iso8601("2015-01-32")
-      {:error, :invalid_date}
-
-  """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO)
-
-  def from_iso8601(<<?-, rest::binary>>, calendar) do
-    with {:ok, %{year: year} = date} <- raw_from_iso8601(rest, calendar) do
-      {:ok, %{date | year: -year}}
-    end
-  end
-
-  def from_iso8601(<<rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar)
-  end
-
-  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
-
-  defp raw_from_iso8601(string, calendar) do
-    with unquote(match_date) <- string,
-         true <- unquote(guard_date) do
-      {year, month, day} = unquote(read_date)
-
-      with {:ok, date} <- new(year, month, day, Calendar.ISO) do
-        convert(date, calendar)
-      end
-    else
-      _ -> {:error, :invalid_format}
-    end
-  end
-
-  @doc """
-  Parses the extended "Dates" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Raises if the format is invalid.
-
-  ## Examples
-
-      iex> Date.from_iso8601!("2015-01-23")
-      ~D[2015-01-23]
-      iex> Date.from_iso8601!("2015:01:23")
-      ** (ArgumentError) cannot parse "2015:01:23" as date, reason: :invalid_format
-
-  """
-  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t
-  def from_iso8601!(string, calendar \\ Calendar.ISO) do
-    case from_iso8601(string, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError, "cannot parse #{inspect(string)} as date, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Converts the given `date` to
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  By default, `Date.to_iso8601/2` returns dates formatted in the "extended"
-  format, for human readability. It also supports the "basic" format through passing the `:basic` option.
-
-  Only supports converting dates which are in the ISO calendar,
-  or other calendars in which the days also start at midnight.
-  Attempting to convert dates from other calendars will raise an `ArgumentError`.
-
-  ### Examples
-
-      iex> Date.to_iso8601(~D[2000-02-28])
-      "2000-02-28"
-
-      iex> Date.to_iso8601(~D[2000-02-28], :basic)
-      "20000228"
-
-      iex> Date.to_iso8601(~N[2000-02-28 00:00:00])
-      "2000-02-28"
-
-  """
-  @spec to_iso8601(Calendar.date(), :extended | :basic) :: String.t()
-  def to_iso8601(date, format \\ :extended)
-
-  def to_iso8601(%{calendar: Calendar.ISO} = date, format) when format in [:basic, :extended] do
-    %{year: year, month: month, day: day} = date
-    Calendar.ISO.date_to_iso8601(year, month, day, format)
-  end
-
-  def to_iso8601(%{calendar: _} = date, format) when format in [:basic, :extended] do
-    date
-    |> convert!(Calendar.ISO)
-    |> to_iso8601()
-  end
-
-  @doc """
-  Converts the given `date` to an Erlang date tuple.
-
-  Only supports converting dates which are in the ISO calendar,
-  or other calendars in which the days also start at midnight.
-  Attempting to convert dates from other calendars will raise.
-
-  ## Examples
-
-      iex> Date.to_erl(~D[2000-01-01])
-      {2000, 1, 1}
-
-      iex> Date.to_erl(~N[2000-01-01 00:00:00])
-      {2000, 1, 1}
-
-  """
-  @spec to_erl(Calendar.date()) :: :calendar.date()
-  def to_erl(date) do
-    %{year: year, month: month, day: day} = convert!(date, Calendar.ISO)
-    {year, month, day}
-  end
-
-  @doc """
-  Converts an Erlang date tuple to a `Date` struct.
-
-  Only supports converting dates which are in the ISO calendar,
-  or other calendars in which the days also start at midnight.
-  Attempting to convert dates from other calendars will return an error tuple.
-
-  ## Examples
-
-      iex> Date.from_erl({2000, 1, 1})
-      {:ok, ~D[2000-01-01]}
-      iex> Date.from_erl({2000, 13, 1})
-      {:error, :invalid_date}
-
-  """
-  @spec from_erl(:calendar.date(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_erl(tuple, calendar \\ Calendar.ISO)
-
-  def from_erl({year, month, day}, calendar) do
-    with {:ok, date} <- new(year, month, day, Calendar.ISO), do: convert(date, calendar)
-  end
-
-  @doc """
-  Converts an Erlang date tuple but raises for invalid dates.
-
-  ## Examples
-
-      iex> Date.from_erl!({2000, 1, 1})
-      ~D[2000-01-01]
-      iex> Date.from_erl!({2000, 13, 1})
-      ** (ArgumentError) cannot convert {2000, 13, 1} to date, reason: :invalid_date
-
-  """
-  @spec from_erl!(:calendar.date(), Calendar.calendar()) :: t
-  def from_erl!(tuple, calendar \\ Calendar.ISO) do
-    case from_erl(tuple, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(tuple)} to date, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Compares two date structs.
-
-  Returns `:gt` if first date is later than the second
-  and `:lt` for vice versa. If the two dates are equal
-  `:eq` is returned.
-
-  ## Examples
-
-      iex> Date.compare(~D[2016-04-16], ~D[2016-04-28])
-      :lt
-
-  This function can also be used to compare across more
-  complex calendar types by considering only the date fields:
-
-      iex> Date.compare(~D[2016-04-16], ~N[2016-04-28 01:23:45])
-      :lt
-      iex> Date.compare(~D[2016-04-16], ~N[2016-04-16 01:23:45])
-      :eq
-      iex> Date.compare(~N[2016-04-16 12:34:56], ~N[2016-04-16 01:23:45])
-      :eq
-
-  """
-  @doc since: "1.4.0"
-  @spec compare(Calendar.date(), Calendar.date()) :: :lt | :eq | :gt
-  def compare(%{calendar: calendar} = date1, %{calendar: calendar} = date2) do
-    %{year: year1, month: month1, day: day1} = date1
-    %{year: year2, month: month2, day: day2} = date2
-
-    case {{year1, month1, day1}, {year2, month2, day2}} do
-      {first, second} when first > second -> :gt
-      {first, second} when first < second -> :lt
-      _ -> :eq
-    end
-  end
-
-  def compare(date1, date2) do
-    if Calendar.compatible_calendars?(date1.calendar, date2.calendar) do
-      case {to_iso_days(date1), to_iso_days(date2)} do
-        {first, second} when first > second -> :gt
-        {first, second} when first < second -> :lt
-        _ -> :eq
-      end
-    else
-      raise ArgumentError, """
-      cannot compare #{inspect(date1)} with #{inspect(date2)}.
-
-      This comparison would be ambiguous as their calendars have incompatible day rollover moments.
-      Specify an exact time of day (using `DateTime`s) to resolve this ambiguity
-      """
-    end
-  end
-
-  @doc """
-  Converts the given `date` from its calendar to the given `calendar`.
-
-  Returns `{:ok, date}` if the calendars are compatible,
-  or `{:error, :incompatible_calendars}` if they are not.
-
-  See also `Calendar.compatible_calendars?/2`.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> Date.convert(~D[2000-01-01], Calendar.Holocene)
-      {:ok, %Date{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert(Calendar.date(), Calendar.calendar()) ::
-          {:ok, t} | {:error, :incompatible_calendars}
-  def convert(%{calendar: calendar, year: year, month: month, day: day}, calendar) do
-    {:ok, %Date{calendar: calendar, year: year, month: month, day: day}}
-  end
-
-  def convert(%{calendar: calendar} = date, target_calendar) do
-    if Calendar.compatible_calendars?(calendar, target_calendar) do
-      result_date =
-        date
-        |> to_iso_days()
-        |> from_iso_days(target_calendar)
-
-      {:ok, result_date}
-    else
-      {:error, :incompatible_calendars}
-    end
-  end
-
-  @doc """
-  Similar to `Date.convert/2`, but raises an `ArgumentError`
-  if the conversion between the two calendars is not possible.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> Date.convert!(~D[2000-01-01], Calendar.Holocene)
-      %Date{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.date(), Calendar.calendar()) :: t
-  def convert!(date, calendar) do
-    case convert(date, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(date)} to target calendar #{inspect(calendar)}, " <>
-                "reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Adds the number of days to the given `date`.
-
-  The days are counted as Gregorian days. The date is returned in the same
-  calendar as it was given in.
-
-  ## Examples
-
-      iex> Date.add(~D[2000-01-03], -2)
-      ~D[2000-01-01]
-      iex> Date.add(~D[2000-01-01], 2)
-      ~D[2000-01-03]
-      iex> Date.add(~N[2000-01-01 09:00:00], 2)
-      ~D[2000-01-03]
-      iex> Date.add(~D[-0010-01-01], -2)
-      ~D[-0011-12-30]
-
-  """
-  @doc since: "1.5.0"
-  @spec add(Calendar.date(), integer()) :: t
-  def add(%{calendar: calendar} = date, days) do
-    {iso_days, fraction} = to_iso_days(date)
-    from_iso_days({iso_days + days, fraction}, calendar)
-  end
-
-  @doc """
-  Calculates the difference between two dates, in a full number of days.
-
-  It returns the number of Gregorian days between the dates. Only `Date`
-  structs that follow the same or compatible calendars can be compared
-  this way. If two calendars are not compatible, it will raise.
-
-  ## Examples
-
-      iex> Date.diff(~D[2000-01-03], ~D[2000-01-01])
-      2
-      iex> Date.diff(~D[2000-01-01], ~D[2000-01-03])
-      -2
-      iex> Date.diff(~D[0000-01-02], ~D[-0001-12-30])
-      3
-      iex> Date.diff(~D[2000-01-01], ~N[2000-01-03 09:00:00])
-      -2
-
-  """
-  @doc since: "1.5.0"
-  @spec diff(Calendar.date(), Calendar.date()) :: integer
-  def diff(%{calendar: Calendar.ISO} = date1, %{calendar: Calendar.ISO} = date2) do
-    %{year: year1, month: month1, day: day1} = date1
-    %{year: year2, month: month2, day: day2} = date2
-
-    Calendar.ISO.date_to_iso_days(year1, month1, day1) -
-      Calendar.ISO.date_to_iso_days(year2, month2, day2)
-  end
-
-  def diff(%{calendar: calendar1} = date1, %{calendar: calendar2} = date2) do
-    if Calendar.compatible_calendars?(calendar1, calendar2) do
-      {days1, _} = to_iso_days(date1)
-      {days2, _} = to_iso_days(date2)
-      days1 - days2
-    else
-      raise ArgumentError,
-            "cannot calculate the difference between #{inspect(date1)} and #{inspect(date2)} because their calendars are not compatible and thus the result would be ambiguous"
-    end
-  end
-
-  defp to_iso_days(%{calendar: Calendar.ISO, year: year, month: month, day: day}) do
-    {Calendar.ISO.date_to_iso_days(year, month, day), {0, 86_400_000_000}}
-  end
-
-  defp to_iso_days(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.naive_datetime_to_iso_days(year, month, day, 0, 0, 0, {0, 0})
-  end
-
-  defp from_iso_days({days, _}, Calendar.ISO) do
-    {year, month, day} = Calendar.ISO.date_from_iso_days(days)
-    %Date{year: year, month: month, day: day, calendar: Calendar.ISO}
-  end
-
-  defp from_iso_days(iso_days, target_calendar) do
-    {year, month, day, _, _, _, _} = target_calendar.naive_datetime_from_iso_days(iso_days)
-    %Date{year: year, month: month, day: day, calendar: target_calendar}
-  end
-
-  @doc """
-  Calculates the day of the week of a given `date`.
-
-  Returns the day of the week as an integer. For the ISO 8601
-  calendar (the default), it is an integer from 1 to 7, where
-  1 is Monday and 7 is Sunday.
-
-  ## Examples
-
-      iex> Date.day_of_week(~D[2016-10-31])
-      1
-      iex> Date.day_of_week(~D[2016-11-01])
-      2
-      iex> Date.day_of_week(~N[2016-11-01 01:23:45])
-      2
-      iex> Date.day_of_week(~D[-0015-10-30])
-      3
-
-  """
-  @doc since: "1.4.0"
-  @spec day_of_week(Calendar.date()) :: non_neg_integer()
-  def day_of_week(date)
-
-  def day_of_week(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.day_of_week(year, month, day)
-  end
-
-  ## Helpers
-
-  defimpl String.Chars do
-    def to_string(%{calendar: calendar, year: year, month: month, day: day}) do
-      calendar.date_to_string(year, month, day)
-    end
-  end
-
-  defimpl Inspect do
-    def inspect(%{calendar: Calendar.ISO, year: year, month: month, day: day}, _) do
-      "~D[" <> Calendar.ISO.date_to_string(year, month, day) <> "]"
-    end
-
-    def inspect(date, opts) do
-      Inspect.Any.inspect(date, opts)
-    end
-  end
-end
@@ -1,132 +0,0 @@
-defmodule Date.Range do
-  @moduledoc """
-  Returns an inclusive range between dates.
-
-  Ranges must be created with the `Date.range/2` function.
-
-  The following fields are public:
-
-    * `:first` - the initial date on the range
-    * `:last` - the last date on the range
-
-  The remaining fields are private and should not be accessed.
-  """
-
-  @type t :: %__MODULE__{
-          first: Date.t(),
-          last: Date.t(),
-          first_in_iso_days: iso_days(),
-          last_in_iso_days: iso_days()
-        }
-
-  @typep iso_days() :: Calendar.iso_days()
-
-  defstruct [:first, :last, :first_in_iso_days, :last_in_iso_days]
-
-  defimpl Enumerable do
-    def member?(%{first: %{calendar: calendar}} = range, %Date{calendar: calendar} = date) do
-      %{
-        first: first,
-        last: last,
-        first_in_iso_days: first_in_iso_days,
-        last_in_iso_days: last_in_iso_days
-      } = range
-
-      %{year: first_year, month: first_month, day: first_day} = first
-      %{year: last_year, month: last_month, day: last_day} = last
-      %{year: year, month: month, day: day} = date
-      first = {first_year, first_month, first_day}
-      last = {last_year, last_month, last_day}
-      date = {year, month, day}
-
-      if first_in_iso_days <= last_in_iso_days do
-        {:ok, date >= first and date <= last}
-      else
-        {:ok, date >= last and date <= first}
-      end
-    end
-
-    def member?(_, _) do
-      {:ok, false}
-    end
-
-    def count(%{first_in_iso_days: first, last_in_iso_days: last}) do
-      {:ok, abs(first - last) + 1}
-    end
-
-    def slice(range) do
-      %{
-        first_in_iso_days: first,
-        last_in_iso_days: last,
-        first: %{calendar: calendar}
-      } = range
-
-      if first <= last do
-        {:ok, last - first + 1, &slice_asc(first + &1, &2, calendar)}
-      else
-        {:ok, first - last + 1, &slice_desc(first - &1, &2, calendar)}
-      end
-    end
-
-    defp slice_asc(current, 1, calendar), do: [date_from_iso_days(current, calendar)]
-
-    defp slice_asc(current, remaining, calendar) do
-      [date_from_iso_days(current, calendar) | slice_asc(current + 1, remaining - 1, calendar)]
-    end
-
-    defp slice_desc(current, 1, calendar), do: [date_from_iso_days(current, calendar)]
-
-    defp slice_desc(current, remaining, calendar) do
-      [date_from_iso_days(current, calendar) | slice_desc(current - 1, remaining - 1, calendar)]
-    end
-
-    def reduce(range, acc, fun) do
-      %{
-        first_in_iso_days: first_in_iso_days,
-        last_in_iso_days: last_in_iso_days,
-        first: %{calendar: calendar}
-      } = range
-
-      up? = first_in_iso_days <= last_in_iso_days
-      reduce(first_in_iso_days, last_in_iso_days, acc, fun, calendar, up?)
-    end
-
-    defp reduce(_x, _y, {:halt, acc}, _fun, _calendar, _up?) do
-      {:halted, acc}
-    end
-
-    defp reduce(x, y, {:suspend, acc}, fun, calendar, up?) do
-      {:suspended, acc, &reduce(x, y, &1, fun, calendar, up?)}
-    end
-
-    defp reduce(x, y, {:cont, acc}, fun, calendar, up? = true) when x <= y do
-      reduce(x + 1, y, fun.(date_from_iso_days(x, calendar), acc), fun, calendar, up?)
-    end
-
-    defp reduce(x, y, {:cont, acc}, fun, calendar, up? = false) when x >= y do
-      reduce(x - 1, y, fun.(date_from_iso_days(x, calendar), acc), fun, calendar, up?)
-    end
-
-    defp reduce(_, _, {:cont, acc}, _fun, _calendar, _up) do
-      {:done, acc}
-    end
-
-    defp date_from_iso_days(days, Calendar.ISO) do
-      {year, month, day} = Calendar.ISO.date_from_iso_days(days)
-      %Date{year: year, month: month, day: day, calendar: Calendar.ISO}
-    end
-
-    defp date_from_iso_days(days, calendar) do
-      {year, month, day, _, _, _, _} =
-        calendar.naive_datetime_from_iso_days({days, {0, 86_400_000_000}})
-
-      %Date{year: year, month: month, day: day, calendar: calendar}
-    end
-  end
-
-  defimpl Inspect do
-    def inspect(%Date.Range{first: first, last: last}, _) do
-      "#DateRange<" <> inspect(first) <> ", " <> inspect(last) <> ">"
-    end
-  end
-end
@@ -1,997 +0,0 @@
-defmodule DateTime do
-  @moduledoc """
-  A datetime implementation with a time zone.
-
-  This datetime can be seen as an ephemeral snapshot
-  of a datetime at a given time zone. For such purposes,
-  it also includes both UTC and Standard offsets, as
-  well as the zone abbreviation field used exclusively
-  for formatting purposes.
-
-  Remember, comparisons in Elixir using `==/2`, `>/2`, `</2` and friends
-  are structural and based on the DateTime struct fields. For proper
-  comparison between datetimes, use the `compare/2` function.
-
-  The functions on this module work with the `DateTime` struct as well
-  as any struct that contains the same fields as the `DateTime` struct.
-  Such functions expect `t:Calendar.datetime/0` in their typespecs
-  (instead of `t:t/0`).
-
-  Developers should avoid creating the `DateTime` struct directly
-  and instead rely on the functions provided by this module as
-  well as the ones in 3rd party calendar libraries.
-
-  ## Where are my functions?
-
-  You will notice this module only contains conversion
-  functions as well as functions that work on UTC. This
-  is because a proper `DateTime` implementation requires a
-  time zone database which currently is not provided as part
-  of Elixir.
-
-  Such may be addressed in upcoming versions, meanwhile,
-  use 3rd party packages to provide `DateTime` building and
-  similar functionality with time zone backing.
-  """
-
-  @enforce_keys [:year, :month, :day, :hour, :minute, :second] ++
-                  [:time_zone, :zone_abbr, :utc_offset, :std_offset]
-
-  defstruct [
-    :year,
-    :month,
-    :day,
-    :hour,
-    :minute,
-    :second,
-    :time_zone,
-    :zone_abbr,
-    :utc_offset,
-    :std_offset,
-    microsecond: {0, 0},
-    calendar: Calendar.ISO
-  ]
-
-  @type t :: %__MODULE__{
-          year: Calendar.year(),
-          month: Calendar.month(),
-          day: Calendar.day(),
-          calendar: Calendar.calendar(),
-          hour: Calendar.hour(),
-          minute: Calendar.minute(),
-          second: Calendar.second(),
-          microsecond: Calendar.microsecond(),
-          time_zone: Calendar.time_zone(),
-          zone_abbr: Calendar.zone_abbr(),
-          utc_offset: Calendar.utc_offset(),
-          std_offset: Calendar.std_offset()
-        }
-
-  @unix_days :calendar.date_to_gregorian_days({1970, 1, 1})
-
-  @doc """
-  Returns the current datetime in UTC.
-
-  ## Examples
-
-      iex> datetime = DateTime.utc_now()
-      iex> datetime.time_zone
-      "Etc/UTC"
-
-  """
-  @spec utc_now(Calendar.calendar()) :: t
-  def utc_now(calendar \\ Calendar.ISO) do
-    System.os_time() |> from_unix!(:native, calendar)
-  end
-
-  @doc """
-  Converts the given Unix time to `DateTime`.
-
-  The integer can be given in different unit
-  according to `System.convert_time_unit/3` and it will
-  be converted to microseconds internally.
-
-  Unix times are always in UTC and therefore the DateTime
-  will be returned in UTC.
-
-  ## Examples
-
-      iex> {:ok, datetime} = DateTime.from_unix(1_464_096_368)
-      iex> datetime
-      #DateTime<2016-05-24 13:26:08Z>
-
-      iex> {:ok, datetime} = DateTime.from_unix(1_432_560_368_868_569, :microsecond)
-      iex> datetime
-      #DateTime<2015-05-25 13:26:08.868569Z>
-
-  The unit can also be an integer as in `t:System.time_unit/0`:
-
-      iex> {:ok, datetime} = DateTime.from_unix(143_256_036_886_856, 1024)
-      iex> datetime
-      #DateTime<6403-03-17 07:05:22.320Z>
-
-  Negative Unix times are supported, up to -62167219200 seconds,
-  which is equivalent to "0000-01-01T00:00:00Z" or 0 Gregorian seconds.
-  """
-  @spec from_unix(integer, :native | System.time_unit(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
-  def from_unix(integer, unit \\ :second, calendar \\ Calendar.ISO) when is_integer(integer) do
-    case Calendar.ISO.from_unix(integer, unit) do
-      {:ok, {year, month, day}, {hour, minute, second}, microsecond} ->
-        iso_datetime = %DateTime{
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond,
-          std_offset: 0,
-          utc_offset: 0,
-          zone_abbr: "UTC",
-          time_zone: "Etc/UTC"
-        }
-
-        convert(iso_datetime, calendar)
-
-      {:error, _} = error ->
-        error
-    end
-  end
-
-  @doc """
-  Converts the given Unix time to `DateTime`.
-
-  The integer can be given in different unit
-  according to `System.convert_time_unit/3` and it will
-  be converted to microseconds internally.
-
-  Unix times are always in UTC and therefore the DateTime
-  will be returned in UTC.
-
-  ## Examples
-
-      # An easy way to get the Unix epoch is passing 0 to this function
-      iex> DateTime.from_unix!(0)
-      #DateTime<1970-01-01 00:00:00Z>
-
-      iex> DateTime.from_unix!(1_464_096_368)
-      #DateTime<2016-05-24 13:26:08Z>
-
-      iex> DateTime.from_unix!(1_432_560_368_868_569, :microsecond)
-      #DateTime<2015-05-25 13:26:08.868569Z>
-
-  """
-  @spec from_unix!(integer, :native | System.time_unit(), Calendar.calendar()) :: t
-  def from_unix!(integer, unit \\ :second, calendar \\ Calendar.ISO) when is_atom(unit) do
-    case from_unix(integer, unit, calendar) do
-      {:ok, datetime} ->
-        datetime
-
-      {:error, :invalid_unix_time} ->
-        raise ArgumentError, "invalid Unix time #{integer}"
-    end
-  end
-
-  @doc """
-  Converts the given `NaiveDateTime` to `DateTime`.
-
-  It expects a time zone to put the NaiveDateTime in.
-  Currently it only supports "Etc/UTC" as time zone.
-
-  ## Examples
-
-      iex> {:ok, datetime} = DateTime.from_naive(~N[2016-05-24 13:26:08.003], "Etc/UTC")
-      iex> datetime
-      #DateTime<2016-05-24 13:26:08.003Z>
-
-  """
-  @doc since: "1.4.0"
-  @spec from_naive(NaiveDateTime.t(), Calendar.time_zone()) :: {:ok, t}
-  def from_naive(naive_datetime, time_zone)
-
-  def from_naive(%NaiveDateTime{} = naive_datetime, "Etc/UTC") do
-    %{
-      calendar: calendar,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      year: year,
-      month: month,
-      day: day
-    } = naive_datetime
-
-    datetime = %DateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      std_offset: 0,
-      utc_offset: 0,
-      zone_abbr: "UTC",
-      time_zone: "Etc/UTC"
-    }
-
-    {:ok, datetime}
-  end
-
-  @doc """
-  Converts the given `NaiveDateTime` to `DateTime`.
-
-  It expects a time zone to put the NaiveDateTime in.
-  Currently it only supports "Etc/UTC" as time zone.
-
-  ## Examples
-
-      iex> DateTime.from_naive!(~N[2016-05-24 13:26:08.003], "Etc/UTC")
-      #DateTime<2016-05-24 13:26:08.003Z>
-
-  """
-  @doc since: "1.4.0"
-  @spec from_naive!(NaiveDateTime.t(), Calendar.time_zone()) :: t
-  def from_naive!(naive_datetime, time_zone) do
-    case from_naive(naive_datetime, time_zone) do
-      {:ok, datetime} ->
-        datetime
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot parse #{inspect(naive_datetime)} to datetime, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Converts the given `datetime` to Unix time.
-
-  The `datetime` is expected to be using the ISO calendar
-  with a year greater than or equal to 0.
-
-  It will return the integer with the given unit,
-  according to `System.convert_time_unit/3`.
-
-  ## Examples
-
-      iex> 1_464_096_368 |> DateTime.from_unix!() |> DateTime.to_unix()
-      1464096368
-
-      iex> dt = %DateTime{calendar: Calendar.ISO, day: 20, hour: 18, microsecond: {273806, 6},
-      ...>                minute: 58, month: 11, second: 19, time_zone: "America/Montevideo",
-      ...>                utc_offset: -10800, std_offset: 3600, year: 2014, zone_abbr: "UYST"}
-      iex> DateTime.to_unix(dt)
-      1416517099
-
-      iex> flamel = %DateTime{calendar: Calendar.ISO, day: 22, hour: 8, microsecond: {527771, 6},
-      ...>                minute: 2, month: 3, second: 25, std_offset: 0, time_zone: "Etc/UTC",
-      ...>                utc_offset: 0, year: 1418, zone_abbr: "UTC"}
-      iex> DateTime.to_unix(flamel)
-      -17412508655
-
-  """
-  @spec to_unix(Calendar.datetime(), System.time_unit()) :: integer
-  def to_unix(datetime, unit \\ :second)
-
-  def to_unix(%{utc_offset: utc_offset, std_offset: std_offset} = datetime, unit) do
-    {days, fraction} = to_iso_days(datetime)
-    unix_units = Calendar.ISO.iso_days_to_unit({days - @unix_days, fraction}, unit)
-    offset_units = System.convert_time_unit(utc_offset + std_offset, :second, unit)
-    unix_units - offset_units
-  end
-
-  @doc """
-  Converts the given `datetime` into a `NaiveDateTime`.
-
-  Because `NaiveDateTime` does not hold time zone information,
-  any time zone related data will be lost during the conversion.
-
-  ## Examples
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 1},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.to_naive(dt)
-      ~N[2000-02-29 23:00:07.0]
-
-  """
-  @spec to_naive(t) :: NaiveDateTime.t()
-  def to_naive(%DateTime{} = datetime) do
-    %DateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    } = datetime
-
-    %NaiveDateTime{
-      year: year,
-      month: month,
-      day: day,
-      calendar: calendar,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    }
-  end
-
-  @doc """
-  Converts a `DateTime` into a `Date`.
-
-  Because `Date` does not hold time nor time zone information,
-  data will be lost during the conversion.
-
-  ## Examples
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.to_date(dt)
-      ~D[2000-02-29]
-
-  """
-  @spec to_date(t) :: Date.t()
-  def to_date(%DateTime{} = datetime) do
-    %{year: year, month: month, day: day, calendar: calendar} = datetime
-    %Date{year: year, month: month, day: day, calendar: calendar}
-  end
-
-  @doc """
-  Converts a `DateTime` into `Time`.
-
-  Because `Time` does not hold date nor time zone information,
-  data will be lost during the conversion.
-
-  ## Examples
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 1},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.to_time(dt)
-      ~T[23:00:07.0]
-
-  """
-  @spec to_time(t) :: Time.t()
-  def to_time(%DateTime{} = datetime) do
-    %{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: calendar} =
-      datetime
-
-    %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    }
-  end
-
-  @doc """
-  Converts the given datetime to
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601) format.
-
-  By default, `DateTime.to_iso8601/2` returns datetimes formatted in the "extended"
-  format, for human readability. It also supports the "basic" format through passing the `:basic` option.
-
-  Only supports converting datetimes which are in the ISO calendar,
-  attempting to convert datetimes from other calendars will raise.
-
-  WARNING: the ISO 8601 datetime format does not contain the time zone nor
-  its abbreviation, which means information is lost when converting to such
-  format.
-
-  ### Examples
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.to_iso8601(dt)
-      "2000-02-29T23:00:07+01:00"
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "UTC",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 0, std_offset: 0, time_zone: "Etc/UTC"}
-      iex> DateTime.to_iso8601(dt)
-      "2000-02-29T23:00:07Z"
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> DateTime.to_iso8601(dt, :extended)
-      "2000-02-29T23:00:07-04:00"
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> DateTime.to_iso8601(dt, :basic)
-      "20000229T230007-0400"
-
-  """
-  @spec to_iso8601(Calendar.datetime(), :extended | :basic) :: String.t()
-  def to_iso8601(datetime, format \\ :extended)
-
-  def to_iso8601(%{calendar: Calendar.ISO} = datetime, format)
-      when format in [:extended, :basic] do
-    %{
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      time_zone: time_zone,
-      zone_abbr: zone_abbr,
-      utc_offset: utc_offset,
-      std_offset: std_offset
-    } = datetime
-
-    Calendar.ISO.datetime_to_iso8601(
-      year,
-      month,
-      day,
-      hour,
-      minute,
-      second,
-      microsecond,
-      time_zone,
-      zone_abbr,
-      utc_offset,
-      std_offset,
-      format
-    )
-  end
-
-  def to_iso8601(%{calendar: _} = datetime, format) when format in [:extended, :basic] do
-    datetime
-    |> convert!(Calendar.ISO)
-    |> to_iso8601(format)
-  end
-
-  @doc """
-  Parses the extended "Date and time of day" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Since ISO 8601 does not include the proper time zone, the given
-  string will be converted to UTC and its offset in seconds will be
-  returned as part of this function. Therefore offset information
-  must be present in the string.
-
-  As specified in the standard, the separator "T" may be omitted if
-  desired as there is no ambiguity within this function.
-
-  Time representations with reduced accuracy are not supported.
-
-  Note that while ISO 8601 allows datetimes to specify 24:00:00 as the
-  zero hour of the next day, this notation is not supported by Elixir.
-
-  ## Examples
-
-      iex> {:ok, datetime, 0} = DateTime.from_iso8601("2015-01-23T23:50:07Z")
-      iex> datetime
-      #DateTime<2015-01-23 23:50:07Z>
-
-      iex> {:ok, datetime, 9000} = DateTime.from_iso8601("2015-01-23T23:50:07.123+02:30")
-      iex> datetime
-      #DateTime<2015-01-23 21:20:07.123Z>
-
-      iex> {:ok, datetime, 9000} = DateTime.from_iso8601("2015-01-23T23:50:07,123+02:30")
-      iex> datetime
-      #DateTime<2015-01-23 21:20:07.123Z>
-
-      iex> {:ok, datetime, 0} = DateTime.from_iso8601("-2015-01-23T23:50:07Z")
-      iex> datetime
-      #DateTime<-2015-01-23 23:50:07Z>
-
-      iex> {:ok, datetime, 9000} = DateTime.from_iso8601("-2015-01-23T23:50:07,123+02:30")
-      iex> datetime
-      #DateTime<-2015-01-23 21:20:07.123Z>
-
-      iex> DateTime.from_iso8601("2015-01-23P23:50:07")
-      {:error, :invalid_format}
-      iex> DateTime.from_iso8601("2015-01-23 23:50:07A")
-      {:error, :invalid_format}
-      iex> DateTime.from_iso8601("2015-01-23T23:50:07")
-      {:error, :missing_offset}
-      iex> DateTime.from_iso8601("2015-01-23 23:50:61")
-      {:error, :invalid_time}
-      iex> DateTime.from_iso8601("2015-01-32 23:50:07")
-      {:error, :invalid_date}
-
-      iex> DateTime.from_iso8601("2015-01-23T23:50:07.123-00:00")
-      {:error, :invalid_format}
-      iex> DateTime.from_iso8601("2015-01-23T23:50:07.123-00:60")
-      {:error, :invalid_format}
-
-  """
-  @doc since: "1.4.0"
-  @spec from_iso8601(String.t(), Calendar.calendar()) ::
-          {:ok, t, Calendar.utc_offset()} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO)
-
-  def from_iso8601(<<?-, rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar, true)
-  end
-
-  def from_iso8601(<<rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar, false)
-  end
-
-  @sep [?\s, ?T]
-  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
-  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
-
-  defp raw_from_iso8601(string, calendar, is_negative_datetime) do
-    with <<unquote(match_date), sep, unquote(match_time), rest::binary>> <- string,
-         true <- unquote(guard_date) and sep in @sep and unquote(guard_time),
-         {microsecond, rest} <- Calendar.ISO.parse_microsecond(rest),
-         {offset, ""} <- Calendar.ISO.parse_offset(rest) do
-      {year, month, day} = unquote(read_date)
-      {hour, minute, second} = unquote(read_time)
-      year = if is_negative_datetime, do: -year, else: year
-
-      cond do
-        not calendar.valid_date?(year, month, day) ->
-          {:error, :invalid_date}
-
-        not calendar.valid_time?(hour, minute, second, microsecond) ->
-          {:error, :invalid_time}
-
-        offset == 0 ->
-          datetime = %DateTime{
-            calendar: calendar,
-            year: year,
-            month: month,
-            day: day,
-            hour: hour,
-            minute: minute,
-            second: second,
-            microsecond: microsecond,
-            std_offset: 0,
-            utc_offset: 0,
-            zone_abbr: "UTC",
-            time_zone: "Etc/UTC"
-          }
-
-          {:ok, datetime, 0}
-
-        is_nil(offset) ->
-          {:error, :missing_offset}
-
-        true ->
-          {_, precision} = microsecond
-
-          datetime =
-            Calendar.ISO.naive_datetime_to_iso_days(
-              year,
-              month,
-              day,
-              hour,
-              minute,
-              second,
-              microsecond
-            )
-            |> apply_tz_offset(offset)
-            |> from_iso_days("Etc/UTC", "UTC", 0, 0, calendar, precision)
-
-          {:ok, %{datetime | microsecond: microsecond}, offset}
-      end
-    else
-      _ -> {:error, :invalid_format}
-    end
-  end
-
-  @doc """
-  Converts the given `datetime` to a string according to its calendar.
-
-  ### Examples
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.to_string(dt)
-      "2000-02-29 23:00:07+01:00 CET Europe/Warsaw"
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "UTC",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 0, std_offset: 0, time_zone: "Etc/UTC"}
-      iex> DateTime.to_string(dt)
-      "2000-02-29 23:00:07Z"
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> DateTime.to_string(dt)
-      "2000-02-29 23:00:07-04:00 AMT America/Manaus"
-
-      iex> dt = %DateTime{year: -100, month: 12, day: 19, zone_abbr: "CET",
-      ...>                hour: 3, minute: 20, second: 31, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Stockholm"}
-      iex> DateTime.to_string(dt)
-      "-0100-12-19 03:20:31+01:00 CET Europe/Stockholm"
-
-  """
-  @spec to_string(Calendar.datetime()) :: String.t()
-  def to_string(%{calendar: calendar} = datetime) do
-    %{
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      time_zone: time_zone,
-      zone_abbr: zone_abbr,
-      utc_offset: utc_offset,
-      std_offset: std_offset
-    } = datetime
-
-    calendar.datetime_to_string(
-      year,
-      month,
-      day,
-      hour,
-      minute,
-      second,
-      microsecond,
-      time_zone,
-      zone_abbr,
-      utc_offset,
-      std_offset
-    )
-  end
-
-  @doc """
-  Compares two datetime structs.
-
-  Returns `:gt` if the first datetime is later than the second
-  and `:lt` for vice versa. If the two datetimes are equal
-  `:eq` is returned.
-
-  Note that both UTC and Standard offsets will be taken into
-  account when comparison is done.
-
-  ## Examples
-
-      iex> dt1 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> dt2 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.compare(dt1, dt2)
-      :gt
-
-  """
-  @doc since: "1.4.0"
-  @spec compare(Calendar.datetime(), Calendar.datetime()) :: :lt | :eq | :gt
-  def compare(
-        %{calendar: _, utc_offset: utc_offset1, std_offset: std_offset1} = datetime1,
-        %{calendar: _, utc_offset: utc_offset2, std_offset: std_offset2} = datetime2
-      ) do
-    {days1, {parts1, ppd1}} =
-      datetime1
-      |> to_iso_days()
-      |> apply_tz_offset(utc_offset1 + std_offset1)
-
-    {days2, {parts2, ppd2}} =
-      datetime2
-      |> to_iso_days()
-      |> apply_tz_offset(utc_offset2 + std_offset2)
-
-    # Ensure fraction tuples have same denominator.
-    iso_days1 = {days1, parts1 * ppd2}
-    iso_days2 = {days2, parts2 * ppd1}
-
-    case {iso_days1, iso_days2} do
-      {first, second} when first > second -> :gt
-      {first, second} when first < second -> :lt
-      _ -> :eq
-    end
-  end
-
-  @doc """
-  Subtracts `datetime2` from `datetime1`.
-
-  The answer can be returned in any `unit` available from `t:System.time_unit/0`.
-
-  Leap seconds are not taken into account.
-
-  This function returns the difference in seconds where seconds are measured
-  according to `Calendar.ISO`.
-
-  ## Examples
-
-      iex> dt1 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> dt2 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> DateTime.diff(dt1, dt2)
-      18000
-      iex> DateTime.diff(dt2, dt1)
-      -18000
-
-  """
-  @doc since: "1.5.0"
-  @spec diff(Calendar.datetime(), Calendar.datetime()) :: integer()
-  def diff(
-        %{utc_offset: utc_offset1, std_offset: std_offset1} = datetime1,
-        %{utc_offset: utc_offset2, std_offset: std_offset2} = datetime2,
-        unit \\ :second
-      ) do
-    naive_diff =
-      (datetime1 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit)) -
-        (datetime2 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit))
-
-    offset_diff = utc_offset2 + std_offset2 - (utc_offset1 + std_offset1)
-    naive_diff + System.convert_time_unit(offset_diff, :second, unit)
-  end
-
-  @doc """
-  Returns the given datetime with the microsecond field truncated to the given
-  precision (`:microsecond`, `millisecond` or `:second`).
-
-  ## Examples
-
-      iex> dt1 = %DateTime{year: 2017, month: 11, day: 7, zone_abbr: "CET",
-      ...>                 hour: 11, minute: 45, second: 18, microsecond: {123456, 6},
-      ...>                 utc_offset: 3600, std_offset: 0, time_zone: "Europe/Paris"}
-      iex> DateTime.truncate(dt1, :microsecond)
-      #DateTime<2017-11-07 11:45:18.123456+01:00 CET Europe/Paris>
-
-      iex> dt2 = %DateTime{year: 2017, month: 11, day: 7, zone_abbr: "CET",
-      ...>                 hour: 11, minute: 45, second: 18, microsecond: {123456, 6},
-      ...>                 utc_offset: 3600, std_offset: 0, time_zone: "Europe/Paris"}
-      iex> DateTime.truncate(dt2, :millisecond)
-      #DateTime<2017-11-07 11:45:18.123+01:00 CET Europe/Paris>
-
-      iex> dt3 = %DateTime{year: 2017, month: 11, day: 7, zone_abbr: "CET",
-      ...>                 hour: 11, minute: 45, second: 18, microsecond: {123456, 6},
-      ...>                 utc_offset: 3600, std_offset: 0, time_zone: "Europe/Paris"}
-      iex> DateTime.truncate(dt3, :second)
-      #DateTime<2017-11-07 11:45:18+01:00 CET Europe/Paris>
-
-  """
-  @doc since: "1.6.0"
-  @spec truncate(t(), :microsecond | :millisecond | :second) :: t()
-  def truncate(%DateTime{microsecond: microsecond} = datetime, precision) do
-    %{datetime | microsecond: Calendar.truncate(microsecond, precision)}
-  end
-
-  @doc """
-  Converts a given `datetime` from one calendar to another.
-
-  If it is not possible to convert unambiguously between the calendars
-  (see `Calendar.compatible_calendars?/2`), an `{:error, :incompatible_calendars}` tuple
-  is returned.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> dt1 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> DateTime.convert(dt1, Calendar.Holocene)
-      {:ok, %DateTime{calendar: Calendar.Holocene, day: 29, hour: 23,
-                      microsecond: {0, 0}, minute: 0, month: 2, second: 7, std_offset: 0,
-                      time_zone: "America/Manaus", utc_offset: -14400, year: 12000,
-                      zone_abbr: "AMT"}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert(Calendar.datetime(), Calendar.calendar()) ::
-          {:ok, t} | {:error, :incompatible_calendars}
-
-  # Keep it multiline for proper function clause errors.
-  def convert(
-        %{
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond,
-          time_zone: time_zone,
-          zone_abbr: zone_abbr,
-          utc_offset: utc_offset,
-          std_offset: std_offset
-        },
-        calendar
-      ) do
-    datetime = %DateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      time_zone: time_zone,
-      zone_abbr: zone_abbr,
-      utc_offset: utc_offset,
-      std_offset: std_offset
-    }
-
-    {:ok, datetime}
-  end
-
-  def convert(%{calendar: dt_calendar, microsecond: {_, precision}} = datetime, calendar) do
-    if Calendar.compatible_calendars?(dt_calendar, calendar) do
-      result_datetime =
-        datetime
-        |> to_iso_days
-        |> from_iso_days(datetime, calendar, precision)
-
-      {:ok, result_datetime}
-    else
-      {:error, :incompatible_calendars}
-    end
-  end
-
-  @doc """
-  Converts a given `datetime` from one calendar to another.
-
-  If it is not possible to convert unambiguously between the calendars
-  (see `Calendar.compatible_calendars?/2`), an ArgumentError is raised.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> dt1 = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "AMT",
-      ...>                 hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                 utc_offset: -14400, std_offset: 0, time_zone: "America/Manaus"}
-      iex> DateTime.convert!(dt1, Calendar.Holocene)
-      %DateTime{calendar: Calendar.Holocene, day: 29, hour: 23,
-                microsecond: {0, 0}, minute: 0, month: 2, second: 7, std_offset: 0,
-                time_zone: "America/Manaus", utc_offset: -14400, year: 12000,
-                zone_abbr: "AMT"}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.datetime(), Calendar.calendar()) :: t | no_return
-  def convert!(datetime, calendar) do
-    case convert(datetime, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, :incompatible_calendars} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(datetime)} to target calendar #{inspect(calendar)}, " <>
-                "reason: #{inspect(datetime.calendar)} and #{inspect(calendar)} have different " <>
-                "day rollover moments, making this conversion ambiguous"
-    end
-  end
-
-  # Keep it multiline for proper function clause errors.
-  defp to_iso_days(%{
-         calendar: calendar,
-         year: year,
-         month: month,
-         day: day,
-         hour: hour,
-         minute: minute,
-         second: second,
-         microsecond: microsecond
-       }) do
-    calendar.naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond)
-  end
-
-  defp from_iso_days(iso_days, datetime, calendar, precision) do
-    %{time_zone: time_zone, zone_abbr: zone_abbr, utc_offset: utc_offset, std_offset: std_offset} =
-      datetime
-
-    from_iso_days(iso_days, time_zone, zone_abbr, utc_offset, std_offset, calendar, precision)
-  end
-
-  defp from_iso_days(iso_days, time_zone, zone_abbr, utc_offset, std_offset, calendar, precision) do
-    {year, month, day, hour, minute, second, {microsecond, _}} =
-      calendar.naive_datetime_from_iso_days(iso_days)
-
-    %DateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: {microsecond, precision},
-      time_zone: time_zone,
-      zone_abbr: zone_abbr,
-      utc_offset: utc_offset,
-      std_offset: std_offset
-    }
-  end
-
-  defp apply_tz_offset(iso_days, offset) do
-    Calendar.ISO.add_day_fraction_to_iso_days(iso_days, -offset, 86400)
-  end
-
-  defimpl String.Chars do
-    def to_string(datetime) do
-      %{
-        calendar: calendar,
-        year: year,
-        month: month,
-        day: day,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond,
-        time_zone: time_zone,
-        zone_abbr: zone_abbr,
-        utc_offset: utc_offset,
-        std_offset: std_offset
-      } = datetime
-
-      calendar.datetime_to_string(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        microsecond,
-        time_zone,
-        zone_abbr,
-        utc_offset,
-        std_offset
-      )
-    end
-  end
-
-  defimpl Inspect do
-    def inspect(%{calendar: Calendar.ISO} = datetime, _) do
-      %{
-        year: year,
-        month: month,
-        day: day,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond,
-        time_zone: time_zone,
-        zone_abbr: zone_abbr,
-        utc_offset: utc_offset,
-        std_offset: std_offset
-      } = datetime
-
-      "#DateTime<" <>
-        Calendar.ISO.datetime_to_string(
-          year,
-          month,
-          day,
-          hour,
-          minute,
-          second,
-          microsecond,
-          time_zone,
-          zone_abbr,
-          utc_offset,
-          std_offset
-        ) <> ">"
-    end
-
-    def inspect(datetime, opts) do
-      Inspect.Any.inspect(datetime, opts)
-    end
-  end
-end
@@ -1,865 +0,0 @@
-defmodule Calendar.ISO do
-  @moduledoc """
-  A calendar implementation that follows to ISO 8601.
-
-  This calendar implements the proleptic Gregorian calendar and
-  is therefore compatible with the calendar used in most countries
-  today. The proleptic means the Gregorian rules for leap years are
-  applied for all time, consequently the dates give different results
-  before the year 1583 from when the Gregorian calendar was adopted.
-
-  Note that while ISO 8601 allows times and datetimes to specify
-  24:00:00 as the zero hour of the next day, this notation is not
-  supported by Elixir.
-  """
-
-  @behaviour Calendar
-
-  @unix_epoch 62_167_219_200
-  unix_start = (315_537_897_600 + @unix_epoch) * -1_000_000
-  unix_end = 315_569_519_999_999_999 - @unix_epoch * 1_000_000
-  @unix_range_microseconds unix_start..unix_end
-
-  @type year :: -9999..9999
-  @type month :: 1..12
-  @type day :: 1..31
-
-  @seconds_per_minute 60
-  @seconds_per_hour 60 * 60
-  # Note that this does _not_ handle leap seconds.
-  @seconds_per_day 24 * 60 * 60
-  @last_second_of_the_day @seconds_per_day - 1
-  @microseconds_per_second 1_000_000
-  @parts_per_day @seconds_per_day * @microseconds_per_second
-
-  @days_per_nonleap_year 365
-  @days_per_leap_year 366
-
-  @months_in_year 12
-
-  @doc false
-  def __match_date__ do
-    quote do
-      [
-        <<y1, y2, y3, y4, ?-, m1, m2, ?-, d1, d2>>,
-        y1 >= ?0 and y1 <= ?9 and y2 >= ?0 and y2 <= ?9 and y3 >= ?0 and y3 <= ?9 and y4 >= ?0 and
-          y4 <= ?9 and m1 >= ?0 and m1 <= ?9 and m2 >= ?0 and m2 <= ?9 and d1 >= ?0 and d1 <= ?9 and
-          d2 >= ?0 and d2 <= ?9,
-        {
-          (y1 - ?0) * 1000 + (y2 - ?0) * 100 + (y3 - ?0) * 10 + (y4 - ?0),
-          (m1 - ?0) * 10 + (m2 - ?0),
-          (d1 - ?0) * 10 + (d2 - ?0)
-        }
-      ]
-    end
-  end
-
-  @doc false
-  def __match_time__ do
-    quote do
-      [
-        <<h1, h2, ?:, i1, i2, ?:, s1, s2>>,
-        h1 >= ?0 and h1 <= ?9 and h2 >= ?0 and h2 <= ?9 and i1 >= ?0 and i1 <= ?9 and i2 >= ?0 and
-          i2 <= ?9 and s1 >= ?0 and s1 <= ?9 and s2 >= ?0 and s2 <= ?9,
-        {
-          (h1 - ?0) * 10 + (h2 - ?0),
-          (i1 - ?0) * 10 + (i2 - ?0),
-          (s1 - ?0) * 10 + (s2 - ?0)
-        }
-      ]
-    end
-  end
-
-  @doc """
-  Returns the `t:Calendar.iso_days/0` format of the specified date.
-
-  ## Examples
-
-      iex> Calendar.ISO.naive_datetime_to_iso_days(0, 1, 1, 0, 0, 0, {0, 6})
-      {0, {0, 86400000000}}
-      iex> Calendar.ISO.naive_datetime_to_iso_days(2000, 1, 1, 12, 0, 0, {0, 6})
-      {730485, {43200000000, 86400000000}}
-      iex> Calendar.ISO.naive_datetime_to_iso_days(2000, 1, 1, 13, 0, 0, {0, 6})
-      {730485, {46800000000, 86400000000}}
-      iex> Calendar.ISO.naive_datetime_to_iso_days(-1, 1, 1, 0, 0, 0, {0, 6})
-      {-365, {0, 86400000000}}
-
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec naive_datetime_to_iso_days(
-          Calendar.year(),
-          Calendar.month(),
-          Calendar.day(),
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond()
-        ) :: Calendar.iso_days()
-  def naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) do
-    {date_to_iso_days(year, month, day), time_to_day_fraction(hour, minute, second, microsecond)}
-  end
-
-  @doc """
-  Converts the `t:Calendar.iso_days/0` format to the datetime format specified by this calendar.
-
-  ## Examples
-
-      iex> Calendar.ISO.naive_datetime_from_iso_days({0, {0, 86400}})
-      {0, 1, 1, 0, 0, 0, {0, 6}}
-      iex> Calendar.ISO.naive_datetime_from_iso_days({730_485, {0, 86400}})
-      {2000, 1, 1, 0, 0, 0, {0, 6}}
-      iex> Calendar.ISO.naive_datetime_from_iso_days({730_485, {43200, 86400}})
-      {2000, 1, 1, 12, 0, 0, {0, 6}}
-      iex> Calendar.ISO.naive_datetime_from_iso_days({-365, {0, 86400000000}})
-      {-1, 1, 1, 0, 0, 0, {0, 6}}
-
-  """
-  @doc since: "1.5.0"
-  @spec naive_datetime_from_iso_days(Calendar.iso_days()) :: {
-          Calendar.year(),
-          Calendar.month(),
-          Calendar.day(),
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond()
-        }
-  @impl true
-  def naive_datetime_from_iso_days({days, day_fraction}) do
-    {year, month, day} = date_from_iso_days(days)
-    {hour, minute, second, microsecond} = time_from_day_fraction(day_fraction)
-    {year, month, day, hour, minute, second, microsecond}
-  end
-
-  @doc """
-  Returns the normalized day fraction of the specified time.
-
-  ## Examples
-
-      iex> Calendar.ISO.time_to_day_fraction(0, 0, 0, {0, 6})
-      {0, 86400000000}
-      iex> Calendar.ISO.time_to_day_fraction(12, 34, 56, {123, 6})
-      {45296000123, 86400000000}
-
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec time_to_day_fraction(
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond()
-        ) :: Calendar.day_fraction()
-  def time_to_day_fraction(0, 0, 0, {0, _}) do
-    {0, @parts_per_day}
-  end
-
-  def time_to_day_fraction(hour, minute, second, {microsecond, _}) do
-    combined_seconds = hour * @seconds_per_hour + minute * @seconds_per_minute + second
-    {combined_seconds * @microseconds_per_second + microsecond, @parts_per_day}
-  end
-
-  @doc """
-  Converts a day fraction to this Calendar's representation of time.
-
-  ## Examples
-
-      iex> Calendar.ISO.time_from_day_fraction({1, 2})
-      {12, 0, 0, {0, 6}}
-      iex> Calendar.ISO.time_from_day_fraction({13, 24})
-      {13, 0, 0, {0, 6}}
-
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec time_from_day_fraction(Calendar.day_fraction()) ::
-          {Calendar.hour(), Calendar.minute(), Calendar.second(), Calendar.microsecond()}
-  def time_from_day_fraction({parts_in_day, parts_per_day}) do
-    total_microseconds = div(parts_in_day * @parts_per_day, parts_per_day)
-
-    {hours, rest_microseconds1} =
-      div_mod(total_microseconds, @seconds_per_hour * @microseconds_per_second)
-
-    {minutes, rest_microseconds2} =
-      div_mod(rest_microseconds1, @seconds_per_minute * @microseconds_per_second)
-
-    {seconds, microseconds} = div_mod(rest_microseconds2, @microseconds_per_second)
-    {hours, minutes, seconds, {microseconds, 6}}
-  end
-
-  # Converts year, month, day to count of days since 0000-01-01.
-  @doc false
-  @doc since: "1.5.0"
-  def date_to_iso_days(0, 1, 1) do
-    0
-  end
-
-  def date_to_iso_days(1970, 1, 1) do
-    719_528
-  end
-
-  def date_to_iso_days(year, month, day) when year in -9999..9999 do
-    true = day <= days_in_month(year, month)
-
-    days_in_previous_years(year) + days_before_month(month) + leap_day_offset(year, month) + day -
-      1
-  end
-
-  # Converts count of days since 0000-01-01 to {year, month, day} tuple.
-  @doc false
-  def date_from_iso_days(days) when days in -3_652_059..3_652_424 do
-    {year, day_of_year} = days_to_year(days)
-    extra_day = if leap_year?(year), do: 1, else: 0
-    {month, day_in_month} = year_day_to_year_date(extra_day, day_of_year)
-    {year, month, day_in_month + 1}
-  end
-
-  defp div_mod(int1, int2) do
-    div = div(int1, int2)
-    rem = int1 - div * int2
-
-    if rem >= 0 do
-      {div, rem}
-    else
-      {div - 1, rem + int2}
-    end
-  end
-
-  @doc """
-  Returns how many days there are in the given year-month.
-
-  ## Examples
-
-      iex> Calendar.ISO.days_in_month(1900, 1)
-      31
-      iex> Calendar.ISO.days_in_month(1900, 2)
-      28
-      iex> Calendar.ISO.days_in_month(2000, 2)
-      29
-      iex> Calendar.ISO.days_in_month(2001, 2)
-      28
-      iex> Calendar.ISO.days_in_month(2004, 2)
-      29
-      iex> Calendar.ISO.days_in_month(2004, 4)
-      30
-      iex> Calendar.ISO.days_in_month(-1, 5)
-      31
-
-  """
-  @spec days_in_month(year, month) :: 28..31
-  @impl true
-  def days_in_month(year, month)
-
-  def days_in_month(year, 2) do
-    if leap_year?(year), do: 29, else: 28
-  end
-
-  def days_in_month(_, month) when month in [4, 6, 9, 11], do: 30
-  def days_in_month(_, month) when month in 1..12, do: 31
-
-  @doc """
-  Returns how many months there are in the given year.
-
-  ## Example
-
-      iex> Calendar.ISO.months_in_year(2004)
-      12
-
-  """
-  @doc since: "1.7.0"
-  @impl true
-  @spec months_in_year(year) :: 12
-  def months_in_year(_year) do
-    @months_in_year
-  end
-
-  @doc """
-  Returns if the given year is a leap year.
-
-  ## Examples
-
-      iex> Calendar.ISO.leap_year?(2000)
-      true
-      iex> Calendar.ISO.leap_year?(2001)
-      false
-      iex> Calendar.ISO.leap_year?(2004)
-      true
-      iex> Calendar.ISO.leap_year?(1900)
-      false
-      iex> Calendar.ISO.leap_year?(-4)
-      true
-
-  """
-  @spec leap_year?(year) :: boolean()
-  @impl true
-  def leap_year?(year) when is_integer(year) do
-    rem(year, 4) === 0 and (rem(year, 100) !== 0 or rem(year, 400) === 0)
-  end
-
-  @doc """
-  Calculates the day of the week from the given `year`, `month`, and `day`.
-
-  It is an integer from 1 to 7, where 1 is Monday and 7 is Sunday.
-
-  ## Examples
-
-      iex> Calendar.ISO.day_of_week(2016, 10, 31)
-      1
-      iex> Calendar.ISO.day_of_week(2016, 11, 1)
-      2
-      iex> Calendar.ISO.day_of_week(2016, 11, 2)
-      3
-      iex> Calendar.ISO.day_of_week(2016, 11, 3)
-      4
-      iex> Calendar.ISO.day_of_week(2016, 11, 4)
-      5
-      iex> Calendar.ISO.day_of_week(2016, 11, 5)
-      6
-      iex> Calendar.ISO.day_of_week(2016, 11, 6)
-      7
-      iex> Calendar.ISO.day_of_week(-99, 1, 31)
-      4
-
-  """
-  @spec day_of_week(year, month, day) :: 1..7
-  @impl true
-  def day_of_week(year, month, day)
-      when is_integer(year) and is_integer(month) and is_integer(day) do
-    Integer.mod(date_to_iso_days(year, month, day) + 5, 7) + 1
-  end
-
-  @doc """
-  Converts the given time into a string.
-
-  ## Examples
-
-      iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 6})
-      "02:02:02.000002"
-      iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 2})
-      "02:02:02.00"
-      iex> Calendar.ISO.time_to_string(2, 2, 2, {2, 0})
-      "02:02:02"
-
-  """
-  @spec time_to_string(
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond()
-        ) :: String.t()
-  @impl true
-  def time_to_string(hour, minute, second, microsecond) do
-    time_to_string(hour, minute, second, microsecond, :extended)
-  end
-
-  def time_to_string(hour, minute, second, {_, 0}, format) do
-    time_to_string_format(hour, minute, second, format)
-  end
-
-  def time_to_string(hour, minute, second, {microsecond, precision}, format) do
-    time_to_string_format(hour, minute, second, format) <>
-      "." <> (microsecond |> zero_pad(6) |> binary_part(0, precision))
-  end
-
-  defp time_to_string_format(hour, minute, second, :extended) do
-    zero_pad(hour, 2) <> ":" <> zero_pad(minute, 2) <> ":" <> zero_pad(second, 2)
-  end
-
-  defp time_to_string_format(hour, minute, second, :basic) do
-    zero_pad(hour, 2) <> zero_pad(minute, 2) <> zero_pad(second, 2)
-  end
-
-  @doc """
-  Converts the given date into a string.
-
-  ## Examples
-
-      iex> Calendar.ISO.date_to_string(2015, 2, 28)
-      "2015-02-28"
-      iex> Calendar.ISO.date_to_string(2017, 8, 1)
-      "2017-08-01"
-      iex> Calendar.ISO.date_to_string(-99, 1, 31)
-      "-0099-01-31"
-
-  """
-  @spec date_to_string(year, month, day) :: String.t()
-  @impl true
-  def date_to_string(year, month, day) do
-    date_to_string(year, month, day, :extended)
-  end
-
-  defp date_to_string(year, month, day, :extended) do
-    zero_pad(year, 4) <> "-" <> zero_pad(month, 2) <> "-" <> zero_pad(day, 2)
-  end
-
-  defp date_to_string(year, month, day, :basic) do
-    zero_pad(year, 4) <> zero_pad(month, 2) <> zero_pad(day, 2)
-  end
-
-  @doc """
-  Converts the datetime (without time zone) into a string.
-
-  ## Examples
-
-      iex> Calendar.ISO.naive_datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 6})
-      "2015-02-28 01:02:03.000004"
-      iex> Calendar.ISO.naive_datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5})
-      "2017-08-01 01:02:03.00000"
-
-  """
-  @impl true
-  @spec naive_datetime_to_string(
-          year,
-          month,
-          day,
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond()
-        ) :: String.t()
-  def naive_datetime_to_string(year, month, day, hour, minute, second, microsecond) do
-    date_to_string(year, month, day) <> " " <> time_to_string(hour, minute, second, microsecond)
-  end
-
-  @doc """
-  Converts the datetime (with time zone) into a string.
-
-  ## Examples
-
-      iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, "Europe/Berlin", "CET", 3600, 0)
-      "2017-08-01 01:02:03.00000+01:00 CET Europe/Berlin"
-      iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, "Europe/Berlin", "CDT", 3600, 3600)
-      "2017-08-01 01:02:03.00000+02:00 CDT Europe/Berlin"
-      iex> Calendar.ISO.datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 5}, "America/Los_Angeles", "PST", -28800, 0)
-      "2015-02-28 01:02:03.00000-08:00 PST America/Los_Angeles"
-      iex> Calendar.ISO.datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 5}, "America/Los_Angeles", "PDT", -28800, 3600)
-      "2015-02-28 01:02:03.00000-07:00 PDT America/Los_Angeles"
-
-  """
-  @impl true
-  @spec datetime_to_string(
-          year,
-          month,
-          day,
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond(),
-          Calendar.time_zone(),
-          Calendar.zone_abbr(),
-          Calendar.utc_offset(),
-          Calendar.std_offset()
-        ) :: String.t()
-  def datetime_to_string(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        microsecond,
-        time_zone,
-        zone_abbr,
-        utc_offset,
-        std_offset
-      ) do
-    date_to_string(year, month, day) <>
-      " " <>
-      time_to_string(hour, minute, second, microsecond) <>
-      offset_to_string(utc_offset, std_offset, time_zone) <>
-      zone_to_string(utc_offset, std_offset, zone_abbr, time_zone)
-  end
-
-  @doc """
-  Determines if the date given is valid according to the proleptic Gregorian calendar.
-
-  ## Examples
-
-      iex> Calendar.ISO.valid_date?(2015, 2, 28)
-      true
-      iex> Calendar.ISO.valid_date?(2015, 2, 30)
-      false
-      iex> Calendar.ISO.valid_date?(-1, 12, 31)
-      true
-      iex> Calendar.ISO.valid_date?(-1, 12, 32)
-      false
-
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec valid_date?(year, month, day) :: boolean
-  def valid_date?(year, month, day) do
-    month in 1..12 and year in -9999..9999 and
-      (is_integer(day) and day >= 1 and day <= days_in_month(year, month))
-  end
-
-  @doc """
-  Determines if the date given is valid according to the proleptic Gregorian calendar.
-  Note that leap seconds are considered valid, but the use of 24:00:00 as the
-  zero hour of the day is considered invalid.
-
-  ## Examples
-
-      iex> Calendar.ISO.valid_time?(10, 50, 25, {3006, 6})
-      true
-      iex> Calendar.ISO.valid_time?(23, 59, 60, {0, 0})
-      true
-      iex> Calendar.ISO.valid_time?(24, 0, 0, {0, 0})
-      false
-
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec valid_time?(Calendar.hour(), Calendar.minute(), Calendar.secon(), Calendar.microsecond()) ::
-          boolean
-  def valid_time?(hour, minute, second, {microsecond, precision}) do
-    hour in 0..23 and minute in 0..59 and second in 0..60 and microsecond in 0..999_999 and
-      precision in 0..6
-  end
-
-  @doc """
-  See `c:Calendar.day_rollover_relative_to_midlight_utc/0` for documentation.
-  """
-  @doc since: "1.5.0"
-  @impl true
-  @spec day_rollover_relative_to_midnight_utc() :: {0, 1}
-  def day_rollover_relative_to_midnight_utc() do
-    {0, 1}
-  end
-
-  defp offset_to_string(utc, std, zone, format \\ :extended)
-  defp offset_to_string(0, 0, "Etc/UTC", _format), do: "Z"
-
-  defp offset_to_string(utc, std, _zone, format) do
-    total = utc + std
-    second = abs(total)
-    minute = second |> rem(3600) |> div(60)
-    hour = div(second, 3600)
-    format_offset(total, hour, minute, format)
-  end
-
-  defp format_offset(total, hour, minute, :extended) do
-    sign(total) <> zero_pad(hour, 2) <> ":" <> zero_pad(minute, 2)
-  end
-
-  defp format_offset(total, hour, minute, :basic) do
-    sign(total) <> zero_pad(hour, 2) <> zero_pad(minute, 2)
-  end
-
-  defp zone_to_string(0, 0, _abbr, "Etc/UTC"), do: ""
-  defp zone_to_string(_, _, abbr, zone), do: " " <> abbr <> " " <> zone
-
-  defp sign(total) when total < 0, do: "-"
-  defp sign(_), do: "+"
-
-  defp zero_pad(val, count) when val >= 0 do
-    num = Integer.to_string(val)
-    :binary.copy("0", count - byte_size(num)) <> num
-  end
-
-  defp zero_pad(val, count) do
-    "-" <> zero_pad(-val, count)
-  end
-
-  ## Helpers
-
-  @doc false
-  def from_unix(integer, unit) when is_integer(integer) do
-    total = System.convert_time_unit(integer, unit, :microsecond)
-
-    if total in @unix_range_microseconds do
-      microseconds = Integer.mod(total, @microseconds_per_second)
-      seconds = @unix_epoch + Integer.floor_div(total, @microseconds_per_second)
-      precision = precision_for_unit(unit)
-      {date, time} = iso_seconds_to_datetime(seconds)
-      {:ok, date, time, {microseconds, precision}}
-    else
-      {:error, :invalid_unix_time}
-    end
-  end
-
-  defp precision_for_unit(unit) do
-    subsecond = div(System.convert_time_unit(1, :second, unit), 10)
-    precision_for_unit(subsecond, 0)
-  end
-
-  defp precision_for_unit(0, precision), do: precision
-  defp precision_for_unit(_, 6), do: 6
-
-  defp precision_for_unit(number, precision),
-    do: precision_for_unit(div(number, 10), precision + 1)
-
-  @doc false
-  @doc since: "1.5.0"
-  def date_to_iso8601(year, month, day, format \\ :extended) do
-    date_to_string(year, month, day, format)
-  end
-
-  @doc false
-  def time_to_iso8601(hour, minute, second, microsecond, format \\ :extended) do
-    time_to_string(hour, minute, second, microsecond, format)
-  end
-
-  @doc false
-  def naive_datetime_to_iso8601(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        microsecond,
-        format \\ :extended
-      ) do
-    date_to_string(year, month, day, format) <>
-      "T" <> time_to_string(hour, minute, second, microsecond, format)
-  end
-
-  @doc false
-  def datetime_to_iso8601(
-        year,
-        month,
-        day,
-        hour,
-        minute,
-        second,
-        microsecond,
-        time_zone,
-        _zone_abbr,
-        utc_offset,
-        std_offset,
-        format \\ :extended
-      ) do
-    date_to_string(year, month, day, format) <>
-      "T" <>
-      time_to_string(hour, minute, second, microsecond, format) <>
-      offset_to_string(utc_offset, std_offset, time_zone, format)
-  end
-
-  @doc false
-  def parse_microsecond("." <> rest) do
-    case parse_microsecond(rest, 0, "") do
-      {"", 0, _} ->
-        :error
-
-      {microsecond, precision, rest} when precision in 1..6 ->
-        pad = String.duplicate("0", 6 - byte_size(microsecond))
-        {{String.to_integer(microsecond <> pad), precision}, rest}
-
-      {microsecond, _precision, rest} ->
-        {{String.to_integer(binary_part(microsecond, 0, 6)), 6}, rest}
-    end
-  end
-
-  def parse_microsecond("," <> rest) do
-    parse_microsecond("." <> rest)
-  end
-
-  def parse_microsecond(rest) do
-    {{0, 0}, rest}
-  end
-
-  defp parse_microsecond(<<head, tail::binary>>, precision, acc) when head in ?0..?9,
-    do: parse_microsecond(tail, precision + 1, <<acc::binary, head>>)
-
-  defp parse_microsecond(rest, precision, acc), do: {acc, precision, rest}
-
-  @doc false
-  def parse_offset(""), do: {nil, ""}
-  def parse_offset("Z"), do: {0, ""}
-  def parse_offset("-00:00"), do: :error
-
-  def parse_offset(<<?+, hour::2-bytes, ?:, min::2-bytes, rest::binary>>),
-    do: parse_offset(1, hour, min, rest)
-
-  def parse_offset(<<?-, hour::2-bytes, ?:, min::2-bytes, rest::binary>>),
-    do: parse_offset(-1, hour, min, rest)
-
-  def parse_offset(<<?+, hour::2-bytes, min::2-bytes, rest::binary>>),
-    do: parse_offset(1, hour, min, rest)
-
-  def parse_offset(<<?-, hour::2-bytes, min::2-bytes, rest::binary>>),
-    do: parse_offset(-1, hour, min, rest)
-
-  def parse_offset(<<?+, hour::2-bytes, rest::binary>>), do: parse_offset(1, hour, "00", rest)
-  def parse_offset(<<?-, hour::2-bytes, rest::binary>>), do: parse_offset(-1, hour, "00", rest)
-  def parse_offset(_), do: :error
-
-  defp parse_offset(sign, hour, min, rest) do
-    with {hour, ""} when hour < 24 <- Integer.parse(hour),
-         {min, ""} when min < 60 <- Integer.parse(min) do
-      {(hour * 60 + min) * 60 * sign, rest}
-    else
-      _ -> :error
-    end
-  end
-
-  @doc false
-  @doc since: "1.5.0"
-  def iso_days_to_unit({days, {parts, ppd}}, unit) do
-    day_microseconds = days * @parts_per_day
-    microseconds = div(parts * @parts_per_day, ppd)
-    System.convert_time_unit(day_microseconds + microseconds, :microsecond, unit)
-  end
-
-  @doc false
-  @doc since: "1.5.0"
-  def add_day_fraction_to_iso_days({days, {parts, ppd}}, add, ppd) do
-    normalize_iso_days(days, parts + add, ppd)
-  end
-
-  def add_day_fraction_to_iso_days({days, {parts, ppd}}, add, add_ppd) do
-    parts = parts * add_ppd
-    add = add * ppd
-    gcd = Integer.gcd(ppd, add_ppd)
-    result_parts = div(parts + add, gcd)
-    result_ppd = div(ppd * add_ppd, gcd)
-    normalize_iso_days(days, result_parts, result_ppd)
-  end
-
-  defp normalize_iso_days(days, parts, ppd) do
-    days_offset = div(parts, ppd)
-    parts = rem(parts, ppd)
-
-    if parts < 0 do
-      {days + days_offset - 1, {parts + ppd, ppd}}
-    else
-      {days + days_offset, {parts, ppd}}
-    end
-  end
-
-  # Note that this function does not add the extra leap day for a leap year.
-  # If you want to add that leap day when appropriate,
-  # add the result of leap_day_offset/2 to the result of days_before_month/1.
-  defp days_before_month(1), do: 0
-  defp days_before_month(2), do: 31
-  defp days_before_month(3), do: 59
-  defp days_before_month(4), do: 90
-  defp days_before_month(5), do: 120
-  defp days_before_month(6), do: 151
-  defp days_before_month(7), do: 181
-  defp days_before_month(8), do: 212
-  defp days_before_month(9), do: 243
-  defp days_before_month(10), do: 273
-  defp days_before_month(11), do: 304
-  defp days_before_month(12), do: 334
-
-  defp leap_day_offset(_year, month) when month < 3, do: 0
-
-  defp leap_day_offset(year, _month) do
-    if leap_year?(year), do: 1, else: 0
-  end
-
-  defp days_to_year(days) when days < 0 do
-    year_estimate = -div(-days, @days_per_nonleap_year) - 1
-
-    {year, days_before_year} =
-      days_to_year(year_estimate, days, days_to_end_of_epoch(year_estimate))
-
-    leap_year_pad = if leap_year?(year), do: 1, else: 0
-    {year, leap_year_pad + @days_per_nonleap_year + days - days_before_year}
-  end
-
-  defp days_to_year(days) do
-    year_estimate = div(days, @days_per_nonleap_year)
-
-    {year, days_before_year} =
-      days_to_year(year_estimate, days, days_in_previous_years(year_estimate))
-
-    {year, days - days_before_year}
-  end
-
-  defp days_to_year(year, days1, days2) when year < 0 and days1 >= days2 do
-    days_to_year(year + 1, days1, days_to_end_of_epoch(year + 1))
-  end
-
-  defp days_to_year(year, days1, days2) when year >= 0 and days1 < days2 do
-    days_to_year(year - 1, days1, days_in_previous_years(year - 1))
-  end
-
-  defp days_to_year(year, _days1, days2) do
-    {year, days2}
-  end
-
-  defp days_to_end_of_epoch(year) when year < 0 do
-    previous_year = year + 1
-
-    div(previous_year, 4) - div(previous_year, 100) + div(previous_year, 400) +
-      previous_year * @days_per_nonleap_year
-  end
-
-  defp days_in_previous_years(0), do: 0
-
-  defp days_in_previous_years(year) do
-    previous_year = year - 1
-
-    Integer.floor_div(previous_year, 4) - Integer.floor_div(previous_year, 100) +
-      Integer.floor_div(previous_year, 400) + previous_year * @days_per_nonleap_year +
-      @days_per_leap_year
-  end
-
-  # Note that 0 is the first day of the month.
-  defp year_day_to_year_date(_extra_day, day_of_year) when day_of_year < 31 do
-    {1, day_of_year}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 59 + extra_day do
-    {2, day_of_year - 31}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 90 + extra_day do
-    {3, day_of_year - (59 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 120 + extra_day do
-    {4, day_of_year - (90 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 151 + extra_day do
-    {5, day_of_year - (120 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 181 + extra_day do
-    {6, day_of_year - (151 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 212 + extra_day do
-    {7, day_of_year - (181 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 243 + extra_day do
-    {8, day_of_year - (212 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 273 + extra_day do
-    {9, day_of_year - (243 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 304 + extra_day do
-    {10, day_of_year - (273 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) when day_of_year < 334 + extra_day do
-    {11, day_of_year - (304 + extra_day)}
-  end
-
-  defp year_day_to_year_date(extra_day, day_of_year) do
-    {12, day_of_year - (334 + extra_day)}
-  end
-
-  defp iso_seconds_to_datetime(seconds) do
-    {days, rest_seconds} = div_mod(seconds, @seconds_per_day)
-
-    date = date_from_iso_days(days)
-    time = seconds_to_time(rest_seconds)
-    {date, time}
-  end
-
-  defp seconds_to_time(seconds) when seconds in 0..@last_second_of_the_day do
-    {hour, rest_seconds} = div_mod(seconds, @seconds_per_hour)
-    {minute, second} = div_mod(rest_seconds, @seconds_per_minute)
-
-    {hour, minute, second}
-  end
-end
@@ -1,920 +0,0 @@
-defmodule NaiveDateTime do
-  @moduledoc """
-  A NaiveDateTime struct (without a time zone) and functions.
-
-  The NaiveDateTime struct contains the fields year, month, day, hour,
-  minute, second, microsecond and calendar. New naive datetimes can be
-  built with the `new/2` and `new/8` functions or using the
-  [`~N`](`Kernel.sigil_N/2`) sigil:
-
-      iex> ~N[2000-01-01 23:00:07]
-      ~N[2000-01-01 23:00:07]
-
-  The date and time fields in the struct can be accessed directly:
-
-      iex> naive = ~N[2000-01-01 23:00:07]
-      iex> naive.year
-      2000
-      iex> naive.second
-      7
-
-  We call them "naive" because this datetime representation does not
-  have a time zone. This means the datetime may not actually exist in
-  certain areas in the world even though it is valid.
-
-  For example, when daylight saving changes are applied by a region,
-  the clock typically moves forward or backward by one hour. This means
-  certain datetimes never occur or may occur more than once. Since
-  `NaiveDateTime` is not validated against a time zone, such errors
-  would go unnoticed.
-
-  The functions of this module work with the `NaiveDateTime` struct as well
-  as any struct that contains the same fields as the `NaiveDateTime` struct,
-  such as `DateTime`. Such functions expect
-  `t:Calendar.naive_datetime/0` in their typespecs (instead of `t:t/0`).
-
-  Developers should avoid creating the NaiveDateTime structs directly
-  and instead, rely on the functions provided by this module as well
-  as the ones in 3rd party calendar libraries.
-
-  ## Comparing naive date times
-
-  Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
-  and based on the `NaiveDateTime` struct fields. For proper comparison
-  between naive datetimes, use the `compare/2` function.
-
-  ## Using epochs
-
-  The `add/3` and `diff/3` functions can be used for computing with
-  date times or retrieving the number of seconds between instants.
-  For example, if there is an interest in computing the number of
-  seconds from the Unix epoch (1970-01-01 00:00:00):
-
-      iex> NaiveDateTime.diff(~N[2010-04-17 14:00:00], ~N[1970-01-01 00:00:00])
-      1271512800
-
-      iex> NaiveDateTime.add(~N[1970-01-01 00:00:00], 1_271_512_800)
-      ~N[2010-04-17 14:00:00]
-
-  Those functions are optimized to deal with common epochs, such
-  as the Unix Epoch above or the Gregorian Epoch (0000-01-01 00:00:00).
-  """
-
-  @enforce_keys [:year, :month, :day, :hour, :minute, :second]
-  defstruct [
-    :year,
-    :month,
-    :day,
-    :hour,
-    :minute,
-    :second,
-    microsecond: {0, 0},
-    calendar: Calendar.ISO
-  ]
-
-  @type t :: %NaiveDateTime{
-          year: Calendar.year(),
-          month: Calendar.month(),
-          day: Calendar.day(),
-          calendar: Calendar.calendar(),
-          hour: Calendar.hour(),
-          minute: Calendar.minute(),
-          second: Calendar.second(),
-          microsecond: Calendar.microsecond()
-        }
-
-  @doc """
-  Returns the current naive datetime in UTC.
-
-  Prefer using `DateTime.utc_now/0` when possible as, opposite
-  to `NaiveDateTime`, it will keep the time zone information.
-
-  ## Examples
-
-      iex> naive_datetime = NaiveDateTime.utc_now()
-      iex> naive_datetime.year >= 2016
-      true
-
-  """
-  @doc since: "1.4.0"
-  @spec utc_now(Calendar.calendar()) :: t
-  def utc_now(calendar \\ Calendar.ISO)
-
-  def utc_now(Calendar.ISO) do
-    {:ok, {year, month, day}, {hour, minute, second}, microsecond} =
-      Calendar.ISO.from_unix(:os.system_time(), :native)
-
-    %NaiveDateTime{
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: Calendar.ISO
-    }
-  end
-
-  def utc_now(calendar) do
-    calendar
-    |> DateTime.utc_now()
-    |> DateTime.to_naive()
-  end
-
-  @doc """
-  Builds a new ISO naive datetime.
-
-  Expects all values to be integers. Returns `{:ok, naive_datetime}`
-  if each entry fits its appropriate range, returns `{:error, reason}`
-  otherwise.
-
-  ## Examples
-
-      iex> NaiveDateTime.new(2000, 1, 1, 0, 0, 0)
-      {:ok, ~N[2000-01-01 00:00:00]}
-      iex> NaiveDateTime.new(2000, 13, 1, 0, 0, 0)
-      {:error, :invalid_date}
-      iex> NaiveDateTime.new(2000, 2, 29, 0, 0, 0)
-      {:ok, ~N[2000-02-29 00:00:00]}
-      iex> NaiveDateTime.new(2000, 2, 30, 0, 0, 0)
-      {:error, :invalid_date}
-      iex> NaiveDateTime.new(2001, 2, 29, 0, 0, 0)
-      {:error, :invalid_date}
-
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1})
-      {:ok, ~N[2000-01-01 23:59:59.0]}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 999_999)
-      {:ok, ~N[2000-01-01 23:59:59.999999]}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 60, 999_999)
-      {:ok, ~N[2000-01-01 23:59:60.999999]}
-      iex> NaiveDateTime.new(2000, 1, 1, 24, 59, 59, 999_999)
-      {:error, :invalid_time}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 60, 59, 999_999)
-      {:error, :invalid_time}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 61, 999_999)
-      {:error, :invalid_time}
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, 1_000_000)
-      {:error, :invalid_time}
-
-      iex> NaiveDateTime.new(2000, 1, 1, 23, 59, 59, {0, 1}, Calendar.ISO)
-      {:ok, ~N[2000-01-01 23:59:59.0]}
-
-  """
-  @spec new(
-          Calendar.year(),
-          Calendar.month(),
-          Calendar.day(),
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond(),
-          Calendar.calendar()
-        ) :: {:ok, t} | {:error, atom}
-  def new(year, month, day, hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
-
-  def new(year, month, day, hour, minute, second, microsecond, calendar)
-      when is_integer(microsecond) do
-    new(year, month, day, hour, minute, second, {microsecond, 6}, calendar)
-  end
-
-  def new(year, month, day, hour, minute, second, microsecond, calendar) do
-    cond do
-      not calendar.valid_date?(year, month, day) ->
-        {:error, :invalid_date}
-
-      not calendar.valid_time?(hour, minute, second, microsecond) ->
-        {:error, :invalid_time}
-
-      true ->
-        naive_datetime = %NaiveDateTime{
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        }
-
-        {:ok, naive_datetime}
-    end
-  end
-
-  @doc """
-  Builds a naive datetime from date and time structs.
-
-  ## Examples
-
-      iex> NaiveDateTime.new(~D[2010-01-13], ~T[23:00:07.005])
-      {:ok, ~N[2010-01-13 23:00:07.005]}
-
-  """
-  @spec new(Date.t(), Time.t()) :: {:ok, t}
-  def new(date, time)
-
-  def new(%Date{calendar: calendar} = date, %Time{calendar: calendar} = time) do
-    %{year: year, month: month, day: day} = date
-    %{hour: hour, minute: minute, second: second, microsecond: microsecond} = time
-
-    naive_datetime = %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    }
-
-    {:ok, naive_datetime}
-  end
-
-  @doc """
-  Adds a specified amount of time to a `NaiveDateTime`.
-
-  Accepts an `integer` in any `unit` available from `t:System.time_unit/0`.
-  Negative values will move backwards in time.
-
-  This operation is only possible if both calendars are convertible to `Calendar.ISO`.
-
-  ## Examples
-
-      # adds seconds by default
-      iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2)
-      ~N[2014-10-02 00:29:12]
-
-      # accepts negative offsets
-      iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], -2)
-      ~N[2014-10-02 00:29:08]
-
-      # can work with other units
-      iex> NaiveDateTime.add(~N[2014-10-02 00:29:10], 2_000, :millisecond)
-      ~N[2014-10-02 00:29:12]
-
-      # keeps the same precision
-      iex> NaiveDateTime.add(~N[2014-10-02 00:29:10.021], 21, :second)
-      ~N[2014-10-02 00:29:31.021]
-
-      # changes below the precision will not be visible
-      iex> hidden = NaiveDateTime.add(~N[2014-10-02 00:29:10], 21, :millisecond)
-      iex> hidden.microsecond # ~N[2014-10-02 00:29:10]
-      {21000, 0}
-
-      # from Gregorian seconds
-      iex> NaiveDateTime.add(~N[0000-01-01 00:00:00], 63_579_428_950)
-      ~N[2014-10-02 00:29:10]
-
-  """
-  @doc since: "1.4.0"
-  @spec add(t, integer, System.time_unit()) :: t
-  def add(%NaiveDateTime{} = naive_datetime, integer, unit \\ :second)
-      when is_integer(integer) do
-    %{microsecond: {_, precision}, calendar: calendar} = naive_datetime
-    ppd = System.convert_time_unit(86400, :second, unit)
-
-    naive_datetime
-    |> to_iso_days()
-    |> Calendar.ISO.add_day_fraction_to_iso_days(integer, ppd)
-    |> from_iso_days(calendar, precision)
-  end
-
-  @doc """
-  Subtracts `naive_datetime2` from `naive_datetime1`.
-
-  The answer can be returned in any `unit` available from `t:System.time_unit/0`.
-
-  This function returns the difference in seconds where seconds are measured
-  according to `Calendar.ISO`.
-
-  ## Examples
-
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10])
-      2
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:12], ~N[2014-10-02 00:29:10], :microsecond)
-      2_000_000
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10.042], ~N[2014-10-02 00:29:10.021], :millisecond)
-      21
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[2014-10-02 00:29:12])
-      -2
-      iex> NaiveDateTime.diff(~N[-0001-10-02 00:29:10], ~N[-0001-10-02 00:29:12])
-      -2
-
-      # to Gregorian seconds
-      iex> NaiveDateTime.diff(~N[2014-10-02 00:29:10], ~N[0000-01-01 00:00:00])
-      63579428950
-
-  """
-  @doc since: "1.4.0"
-  @spec diff(t, t, System.time_unit()) :: integer
-  def diff(
-        %NaiveDateTime{} = naive_datetime1,
-        %NaiveDateTime{} = naive_datetime2,
-        unit \\ :second
-      ) do
-    if not Calendar.compatible_calendars?(naive_datetime1.calendar, naive_datetime2.calendar) do
-      raise ArgumentError,
-            "cannot calculate the difference between #{inspect(naive_datetime1)} and " <>
-              "#{inspect(naive_datetime2)} because their calendars are not compatible " <>
-              "and thus the result would be ambiguous"
-    end
-
-    units1 = naive_datetime1 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit)
-    units2 = naive_datetime2 |> to_iso_days() |> Calendar.ISO.iso_days_to_unit(unit)
-    units1 - units2
-  end
-
-  @doc """
-  Returns the given naive datetime with the microsecond field truncated to the
-  given precision (`:microsecond`, `:millisecond` or `:second`).
-
-  ## Examples
-
-      iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :microsecond)
-      ~N[2017-11-06 00:23:51.123456]
-
-      iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :millisecond)
-      ~N[2017-11-06 00:23:51.123]
-
-      iex> NaiveDateTime.truncate(~N[2017-11-06 00:23:51.123456], :second)
-      ~N[2017-11-06 00:23:51]
-
-  """
-  @doc since: "1.6.0"
-  @spec truncate(t(), :microsecond | :millisecond | :second) :: t()
-  def truncate(%NaiveDateTime{microsecond: microsecond} = naive_datetime, precision) do
-    %{naive_datetime | microsecond: Calendar.truncate(microsecond, precision)}
-  end
-
-  @doc """
-  Converts a `NaiveDateTime` into a `Date`.
-
-  Because `Date` does not hold time information,
-  data will be lost during the conversion.
-
-  ## Examples
-
-      iex> NaiveDateTime.to_date(~N[2002-01-13 23:00:07])
-      ~D[2002-01-13]
-
-  """
-  @spec to_date(t) :: Date.t()
-  def to_date(%NaiveDateTime{year: year, month: month, day: day, calendar: calendar}) do
-    %Date{year: year, month: month, day: day, calendar: calendar}
-  end
-
-  @doc """
-  Converts a `NaiveDateTime` into `Time`.
-
-  Because `Time` does not hold date information,
-  data will be lost during the conversion.
-
-  ## Examples
-
-      iex> NaiveDateTime.to_time(~N[2002-01-13 23:00:07])
-      ~T[23:00:07]
-
-  """
-  @spec to_time(t) :: Time.t()
-  def to_time(%NaiveDateTime{} = naive_datetime) do
-    %{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    } = naive_datetime
-
-    %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    }
-  end
-
-  @doc """
-  Converts the given naive datetime to a string according to its calendar.
-
-  ### Examples
-
-      iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13])
-      "2000-02-28 23:00:13"
-      iex> NaiveDateTime.to_string(~N[2000-02-28 23:00:13.001])
-      "2000-02-28 23:00:13.001"
-      iex> NaiveDateTime.to_string(~N[-0100-12-15 03:20:31])
-      "-0100-12-15 03:20:31"
-
-  This function can also be used to convert a DateTime to a string without
-  the time zone information:
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> NaiveDateTime.to_string(dt)
-      "2000-02-29 23:00:07"
-
-  """
-  @spec to_string(Calendar.naive_datetime()) :: String.t()
-  def to_string(%{calendar: calendar} = naive_datetime) do
-    %{
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    } = naive_datetime
-
-    calendar.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
-  end
-
-  @doc """
-  Parses the extended "Date and time of day" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Time zone offset may be included in the string but they will be
-  simply discarded as such information is not included in naive date
-  times.
-
-  As specified in the standard, the separator "T" may be omitted if
-  desired as there is no ambiguity within this function.
-
-  Time representations with reduced accuracy are not supported.
-
-  Note that while ISO 8601 allows datetimes to specify 24:00:00 as the
-  zero hour of the next day, this notation is not supported by Elixir.
-
-  ## Examples
-
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07")
-      {:ok, ~N[2015-01-23 23:50:07]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07")
-      {:ok, ~N[2015-01-23 23:50:07]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07Z")
-      {:ok, ~N[2015-01-23 23:50:07]}
-
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0")
-      {:ok, ~N[2015-01-23 23:50:07.0]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07,0123456")
-      {:ok, ~N[2015-01-23 23:50:07.012345]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07.0123456")
-      {:ok, ~N[2015-01-23 23:50:07.012345]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123Z")
-      {:ok, ~N[2015-01-23 23:50:07.123]}
-
-      iex> NaiveDateTime.from_iso8601("2015-01-23P23:50:07")
-      {:error, :invalid_format}
-      iex> NaiveDateTime.from_iso8601("2015:01:23 23-50-07")
-      {:error, :invalid_format}
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:07A")
-      {:error, :invalid_format}
-      iex> NaiveDateTime.from_iso8601("2015-01-23 23:50:61")
-      {:error, :invalid_time}
-      iex> NaiveDateTime.from_iso8601("2015-01-32 23:50:07")
-      {:error, :invalid_date}
-
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+02:30")
-      {:ok, ~N[2015-01-23 23:50:07.123]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123+00:00")
-      {:ok, ~N[2015-01-23 23:50:07.123]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-02:30")
-      {:ok, ~N[2015-01-23 23:50:07.123]}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:00")
-      {:error, :invalid_format}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-00:60")
-      {:error, :invalid_format}
-      iex> NaiveDateTime.from_iso8601("2015-01-23T23:50:07.123-24:00")
-      {:error, :invalid_format}
-
-  """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO)
-
-  def from_iso8601(<<?-, rest::binary>>, calendar) do
-    with {:ok, %{year: year} = naive_datetime} <- raw_from_iso8601(rest, calendar) do
-      {:ok, %{naive_datetime | year: -year}}
-    end
-  end
-
-  def from_iso8601(<<rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar)
-  end
-
-  @sep [?\s, ?T]
-  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
-  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
-
-  defp raw_from_iso8601(string, calendar) do
-    with <<unquote(match_date), sep, unquote(match_time), rest::binary>> <- string,
-         true <- unquote(guard_date) and sep in @sep and unquote(guard_time),
-         {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
-         {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
-      {year, month, day} = unquote(read_date)
-      {hour, min, sec} = unquote(read_time)
-
-      with {:ok, utc_date} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO) do
-        convert(utc_date, calendar)
-      end
-    else
-      _ -> {:error, :invalid_format}
-    end
-  end
-
-  @doc """
-  Parses the extended "Date and time of day" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Raises if the format is invalid.
-
-  ## Examples
-
-      iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07.123Z")
-      ~N[2015-01-23 23:50:07.123]
-      iex> NaiveDateTime.from_iso8601!("2015-01-23T23:50:07,123Z")
-      ~N[2015-01-23 23:50:07.123]
-      iex> NaiveDateTime.from_iso8601!("2015-01-23P23:50:07")
-      ** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive datetime, reason: :invalid_format
-
-  """
-  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t | no_return
-  def from_iso8601!(string, calendar \\ Calendar.ISO) do
-    case from_iso8601(string, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot parse #{inspect(string)} as naive datetime, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Converts the given naive datetime to
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  By default, `NaiveDateTime.to_iso8601/2` returns naive datetimes formatted in the "extended"
-  format, for human readability. It also supports the "basic" format through passing the `:basic` option.
-
-  Only supports converting naive datetimes which are in the ISO calendar,
-  attempting to convert naive datetimes from other calendars will raise.
-
-  ### Examples
-
-      iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13])
-      "2000-02-28T23:00:13"
-
-      iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001])
-      "2000-02-28T23:00:13.001"
-
-      iex> NaiveDateTime.to_iso8601(~N[2000-02-28 23:00:13.001], :basic)
-      "20000228T230013.001"
-
-  This function can also be used to convert a DateTime to ISO 8601 without
-  the time zone information:
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> NaiveDateTime.to_iso8601(dt)
-      "2000-02-29T23:00:07"
-
-  """
-  @spec to_iso8601(Calendar.naive_datetime(), :basic | :extended) :: String.t()
-  def to_iso8601(naive_datetime, format \\ :extended)
-
-  def to_iso8601(%{calendar: Calendar.ISO} = naive_datetime, format)
-      when format in [:basic, :extended] do
-    %{
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    } = naive_datetime
-
-    Calendar.ISO.naive_datetime_to_iso8601(
-      year,
-      month,
-      day,
-      hour,
-      minute,
-      second,
-      microsecond,
-      format
-    )
-  end
-
-  def to_iso8601(%{calendar: _} = naive_datetime, format) when format in [:basic, :extended] do
-    naive_datetime
-    |> convert!(Calendar.ISO)
-    |> to_iso8601(format)
-  end
-
-  @doc """
-  Converts a `NaiveDateTime` struct to an Erlang datetime tuple.
-
-  Only supports converting naive datetimes which are in the ISO calendar,
-  attempting to convert naive datetimes from other calendars will raise.
-
-  WARNING: Loss of precision may occur, as Erlang time tuples only store
-  hour/minute/second.
-
-  ## Examples
-
-      iex> NaiveDateTime.to_erl(~N[2000-01-01 13:30:15])
-      {{2000, 1, 1}, {13, 30, 15}}
-
-  This function can also be used to convert a DateTime to a erl format
-  without the time zone information:
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> NaiveDateTime.to_erl(dt)
-      {{2000, 2, 29}, {23, 00, 07}}
-
-  """
-  @spec to_erl(Calendar.naive_datetime()) :: :calendar.datetime()
-  def to_erl(%{calendar: _} = naive_datetime) do
-    %{year: year, month: month, day: day, hour: hour, minute: minute, second: second} =
-      convert!(naive_datetime, Calendar.ISO)
-
-    {{year, month, day}, {hour, minute, second}}
-  end
-
-  @doc """
-  Converts an Erlang datetime tuple to a `NaiveDateTime` struct.
-
-  Attempting to convert an invalid ISO calendar date will produce an error tuple.
-
-  ## Examples
-
-      iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}})
-      {:ok, ~N[2000-01-01 13:30:15]}
-      iex> NaiveDateTime.from_erl({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
-      {:ok, ~N[2000-01-01 13:30:15.005]}
-      iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
-      {:error, :invalid_date}
-      iex> NaiveDateTime.from_erl({{2000, 13, 1}, {13, 30, 15}})
-      {:error, :invalid_date}
-
-  """
-  @spec from_erl(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
-  def from_erl(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
-
-  def from_erl({{year, month, day}, {hour, minute, second}}, microsecond, calendar) do
-    with {:ok, utc_date} <- new(year, month, day, hour, minute, second, microsecond),
-         do: convert(utc_date, calendar)
-  end
-
-  @doc """
-  Converts an Erlang datetime tuple to a `NaiveDateTime` struct.
-
-  Raises if the datetime is invalid.
-  Attempting to convert an invalid ISO calendar date will produce an error tuple.
-
-  ## Examples
-
-      iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}})
-      ~N[2000-01-01 13:30:15]
-      iex> NaiveDateTime.from_erl!({{2000, 1, 1}, {13, 30, 15}}, {5000, 3})
-      ~N[2000-01-01 13:30:15.005]
-      iex> NaiveDateTime.from_erl!({{2000, 13, 1}, {13, 30, 15}})
-      ** (ArgumentError) cannot convert {{2000, 13, 1}, {13, 30, 15}} to naive datetime, reason: :invalid_date
-
-  """
-  @spec from_erl!(:calendar.datetime(), Calendar.microsecond(), Calendar.calendar()) ::
-          t | no_return
-  def from_erl!(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
-    case from_erl(tuple, microsecond, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(tuple)} to naive datetime, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Compares two `NaiveDateTime` structs.
-
-  Returns `:gt` if first is later than the second
-  and `:lt` for vice versa. If the two NaiveDateTime
-  are equal `:eq` is returned.
-
-  ## Examples
-
-      iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15], ~N[2016-04-28 16:19:25])
-      :lt
-      iex> NaiveDateTime.compare(~N[2016-04-16 13:30:15.1], ~N[2016-04-16 13:30:15.01])
-      :gt
-
-  This function can also be used to compare a DateTime without
-  the time zone information:
-
-      iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
-      ...>                hour: 23, minute: 0, second: 7, microsecond: {0, 0},
-      ...>                utc_offset: 3600, std_offset: 0, time_zone: "Europe/Warsaw"}
-      iex> NaiveDateTime.compare(dt, ~N[2000-02-29 23:00:07])
-      :eq
-      iex> NaiveDateTime.compare(dt, ~N[2000-01-29 23:00:07])
-      :gt
-      iex> NaiveDateTime.compare(dt, ~N[2000-03-29 23:00:07])
-      :lt
-
-  """
-  @doc since: "1.4.0"
-  @spec compare(Calendar.naive_datetime(), Calendar.naive_datetime()) :: :lt | :eq | :gt
-  def compare(%{calendar: calendar1} = naive_datetime1, %{calendar: calendar2} = naive_datetime2) do
-    if Calendar.compatible_calendars?(calendar1, calendar2) do
-      case {to_iso_days(naive_datetime1), to_iso_days(naive_datetime2)} do
-        {first, second} when first > second -> :gt
-        {first, second} when first < second -> :lt
-        _ -> :eq
-      end
-    else
-      raise ArgumentError, """
-      cannot compare #{inspect(naive_datetime1)} with #{inspect(naive_datetime2)}.
-
-      This comparison would be ambiguous as their calendars have incompatible day rollover moments.
-      Specify an exact time of day (using `DateTime`s) to resolve this ambiguity
-      """
-    end
-  end
-
-  @doc """
-  Converts the given `naive_datetime` from one calendar to another.
-
-  If it is not possible to convert unambiguously between the calendars
-  (see `Calendar.compatible_calendars?/2`), an `{:error, :incompatible_calendars}` tuple
-  is returned.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> NaiveDateTime.convert(~N[2000-01-01 13:30:15], Calendar.Holocene)
-      {:ok, %NaiveDateTime{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1,
-                           hour: 13, minute: 30, second: 15, microsecond: {0, 0}}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert(Calendar.naive_datetime(), Calendar.calendar()) ::
-          {:ok, t} | {:error, :incompatible_calendars}
-
-  # Keep it multiline for proper function clause errors.
-  def convert(
-        %{
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        },
-        calendar
-      ) do
-    naive_datetime = %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    }
-
-    {:ok, naive_datetime}
-  end
-
-  def convert(%{calendar: ndt_calendar, microsecond: {_, precision}} = naive_datetime, calendar) do
-    if Calendar.compatible_calendars?(ndt_calendar, calendar) do
-      result_naive_datetime =
-        naive_datetime
-        |> to_iso_days
-        |> from_iso_days(calendar, precision)
-
-      {:ok, result_naive_datetime}
-    else
-      {:error, :incompatible_calendars}
-    end
-  end
-
-  @doc """
-  Converts the given `naive_datetime` from one calendar to another.
-
-  If it is not possible to convert unambiguously between the calendars
-  (see `Calendar.compatible_calendars?/2`), an ArgumentError is raised.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> NaiveDateTime.convert!(~N[2000-01-01 13:30:15], Calendar.Holocene)
-      %NaiveDateTime{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1,
-                     hour: 13, minute: 30, second: 15, microsecond: {0, 0}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.naive_datetime(), Calendar.calendar()) :: t
-  def convert!(naive_datetime, calendar) do
-    case convert(naive_datetime, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, :incompatible_calendars} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(naive_datetime)} to target calendar #{inspect(calendar)}, " <>
-                "reason: #{inspect(naive_datetime.calendar)} and #{inspect(calendar)} " <>
-                "have different day rollover moments, making this conversion ambiguous"
-    end
-  end
-
-  ## Helpers
-
-  # Keep it multiline for proper function clause errors.
-  defp to_iso_days(%{
-         calendar: calendar,
-         year: year,
-         month: month,
-         day: day,
-         hour: hour,
-         minute: minute,
-         second: second,
-         microsecond: microsecond
-       }) do
-    calendar.naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond)
-  end
-
-  defp from_iso_days(iso_days, calendar, precision) do
-    {year, month, day, hour, minute, second, {microsecond, _}} =
-      calendar.naive_datetime_from_iso_days(iso_days)
-
-    %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: {microsecond, precision}
-    }
-  end
-
-  defimpl String.Chars do
-    def to_string(naive_datetime) do
-      %{
-        calendar: calendar,
-        year: year,
-        month: month,
-        day: day,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond
-      } = naive_datetime
-
-      calendar.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
-    end
-  end
-
-  defimpl Inspect do
-    def inspect(%{calendar: Calendar.ISO} = naive_datetime, _) do
-      %{
-        year: year,
-        month: month,
-        day: day,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond
-      } = naive_datetime
-
-      formatted =
-        Calendar.ISO.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
-
-      "~N[" <> formatted <> "]"
-    end
-
-    def inspect(naive, opts) do
-      Inspect.Any.inspect(naive, opts)
-    end
-  end
-end
@@ -1,673 +0,0 @@
-defmodule Time do
-  @moduledoc """
-  A Time struct and functions.
-
-  The Time struct contains the fields hour, minute, second and microseconds.
-  New times can be built with the `new/4` function or using the
-  [`~T`](`Kernel.sigil_T/2`) sigil:
-
-      iex> ~T[23:00:07.001]
-      ~T[23:00:07.001]
-
-  Both `new/4` and sigil return a struct where the time fields can
-  be accessed directly:
-
-      iex> time = ~T[23:00:07.001]
-      iex> time.hour
-      23
-      iex> time.microsecond
-      {1000, 3}
-
-  The functions on this module work with the `Time` struct as well
-  as any struct that contains the same fields as the `Time` struct,
-  such as `NaiveDateTime` and `DateTime`. Such functions expect
-  `t:Calendar.time/0` in their typespecs (instead of `t:t/0`).
-
-  Developers should avoid creating the Time structs directly
-  and instead rely on the functions provided by this module as well
-  as the ones in 3rd party calendar libraries.
-
-  ## Comparing times
-
-  Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
-  and based on the `Time` struct fields. For proper comparison between
-  times, use the `compare/2` function.
-  """
-
-  @enforce_keys [:hour, :minute, :second]
-  defstruct [:hour, :minute, :second, microsecond: {0, 0}, calendar: Calendar.ISO]
-
-  @type t :: %Time{
-          hour: Calendar.hour(),
-          minute: Calendar.minute(),
-          second: Calendar.second(),
-          microsecond: Calendar.microsecond(),
-          calendar: Calendar.calendar()
-        }
-
-  @doc """
-  Returns the current time in UTC.
-
-  ## Examples
-
-      iex> time = Time.utc_now()
-      iex> time.hour >= 0
-      true
-
-  """
-  @doc since: "1.4.0"
-  @spec utc_now(Calendar.calendar()) :: t
-  def utc_now(calendar \\ Calendar.ISO) do
-    {:ok, _, time, microsecond} = Calendar.ISO.from_unix(:os.system_time(), :native)
-    {hour, minute, second} = time
-
-    iso_time = %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: Calendar.ISO
-    }
-
-    convert!(iso_time, calendar)
-  end
-
-  @doc """
-  Builds a new time.
-
-  Expects all values to be integers. Returns `{:ok, time}` if each
-  entry fits its appropriate range, returns `{:error, reason}` otherwise.
-
-  Note a time may have 60 seconds in case of leap seconds. Microseconds
-  can also be given with a precision, which must be an integer between
-  0 and 6.
-
-  ## Examples
-
-      iex> Time.new(0, 0, 0, 0)
-      {:ok, ~T[00:00:00.000000]}
-      iex> Time.new(23, 59, 59, 999_999)
-      {:ok, ~T[23:59:59.999999]}
-      iex> Time.new(23, 59, 60, 999_999)
-      {:ok, ~T[23:59:60.999999]}
-
-      # Time with microseconds and their precision
-      iex> Time.new(23, 59, 60, {10_000, 2})
-      {:ok, ~T[23:59:60.01]}
-
-      iex> Time.new(24, 59, 59, 999_999)
-      {:error, :invalid_time}
-      iex> Time.new(23, 60, 59, 999_999)
-      {:error, :invalid_time}
-      iex> Time.new(23, 59, 61, 999_999)
-      {:error, :invalid_time}
-      iex> Time.new(23, 59, 59, 1_000_000)
-      {:error, :invalid_time}
-
-      # Invalid precision
-      Time.new(23, 59, 59, {999_999, 10})
-      {:error, :invalid_time}
-
-  """
-  @spec new(
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond() | integer,
-          Calendar.calendar()
-        ) :: {:ok, t} | {:error, atom}
-  def new(hour, minute, second, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
-
-  def new(hour, minute, second, microsecond, calendar) when is_integer(microsecond) do
-    new(hour, minute, second, {microsecond, 6}, calendar)
-  end
-
-  def new(hour, minute, second, {microsecond, precision}, calendar)
-      when is_integer(hour) and is_integer(minute) and is_integer(second) and
-             is_integer(microsecond) and is_integer(precision) do
-    case calendar.valid_time?(hour, minute, second, {microsecond, precision}) do
-      true ->
-        time = %Time{
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: {microsecond, precision},
-          calendar: calendar
-        }
-
-        {:ok, time}
-
-      false ->
-        {:error, :invalid_time}
-    end
-  end
-
-  @doc """
-  Converts the given `time` to a string.
-
-  ### Examples
-
-      iex> Time.to_string(~T[23:00:00])
-      "23:00:00"
-      iex> Time.to_string(~T[23:00:00.001])
-      "23:00:00.001"
-      iex> Time.to_string(~T[23:00:00.123456])
-      "23:00:00.123456"
-
-      iex> Time.to_string(~N[2015-01-01 23:00:00.001])
-      "23:00:00.001"
-      iex> Time.to_string(~N[2015-01-01 23:00:00.123456])
-      "23:00:00.123456"
-
-  """
-  @spec to_string(Calendar.time()) :: String.t()
-  def to_string(time)
-
-  def to_string(%{
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond,
-        calendar: calendar
-      }) do
-    calendar.time_to_string(hour, minute, second, microsecond)
-  end
-
-  @doc """
-  Parses the extended "Local time" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Time zone offset may be included in the string but they will be
-  simply discarded as such information is not included in times.
-
-  As specified in the standard, the separator "T" may be omitted if
-  desired as there is no ambiguity within this function.
-
-  Time representations with reduced accuracy are not supported.
-
-  Note that while ISO 8601 allows times to specify 24:00:00 as the
-  zero hour of the next day, this notation is not supported by Elixir.
-
-  ## Examples
-
-      iex> Time.from_iso8601("23:50:07")
-      {:ok, ~T[23:50:07]}
-      iex> Time.from_iso8601("23:50:07Z")
-      {:ok, ~T[23:50:07]}
-      iex> Time.from_iso8601("T23:50:07Z")
-      {:ok, ~T[23:50:07]}
-
-      iex> Time.from_iso8601("23:50:07,0123456")
-      {:ok, ~T[23:50:07.012345]}
-      iex> Time.from_iso8601("23:50:07.0123456")
-      {:ok, ~T[23:50:07.012345]}
-      iex> Time.from_iso8601("23:50:07.123Z")
-      {:ok, ~T[23:50:07.123]}
-
-      iex> Time.from_iso8601("2015:01:23 23-50-07")
-      {:error, :invalid_format}
-      iex> Time.from_iso8601("23:50:07A")
-      {:error, :invalid_format}
-      iex> Time.from_iso8601("23:50:07.")
-      {:error, :invalid_format}
-      iex> Time.from_iso8601("23:50:61")
-      {:error, :invalid_time}
-
-  """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-  def from_iso8601(string, calendar \\ Calendar.ISO)
-
-  def from_iso8601(<<?T, rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar)
-  end
-
-  def from_iso8601(<<rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar)
-  end
-
-  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
-
-  defp raw_from_iso8601(string, calendar) do
-    with <<unquote(match_time), rest::binary>> <- string,
-         true <- unquote(guard_time),
-         {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
-         {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
-      {hour, min, sec} = unquote(read_time)
-
-      with {:ok, utc_time} <- new(hour, min, sec, microsec, Calendar.ISO) do
-        convert(utc_time, calendar)
-      end
-    else
-      _ -> {:error, :invalid_format}
-    end
-  end
-
-  @doc """
-  Parses the extended "Local time" format described by
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  Raises if the format is invalid.
-
-  ## Examples
-
-      iex> Time.from_iso8601!("23:50:07,123Z")
-      ~T[23:50:07.123]
-      iex> Time.from_iso8601!("23:50:07.123Z")
-      ~T[23:50:07.123]
-      iex> Time.from_iso8601!("2015:01:23 23-50-07")
-      ** (ArgumentError) cannot parse "2015:01:23 23-50-07" as time, reason: :invalid_format
-
-  """
-  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t
-  def from_iso8601!(string, calendar \\ Calendar.ISO) do
-    case from_iso8601(string, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError, "cannot parse #{inspect(string)} as time, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Converts the given time to
-  [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
-
-  By default, `Time.to_iso8601/2` returns times formatted in the "extended"
-  format, for human readability. It also supports the "basic" format through
-  passing the `:basic` option.
-
-  ### Examples
-
-      iex> Time.to_iso8601(~T[23:00:13])
-      "23:00:13"
-
-      iex> Time.to_iso8601(~T[23:00:13.001])
-      "23:00:13.001"
-
-      iex> Time.to_iso8601(~T[23:00:13.001], :basic)
-      "230013.001"
-
-      iex> Time.to_iso8601(~N[2010-04-17 23:00:13])
-      "23:00:13"
-
-  """
-  @spec to_iso8601(Calendar.time(), :extended | :basic) :: String.t()
-  def to_iso8601(time, format \\ :extended)
-
-  def to_iso8601(%{calendar: Calendar.ISO} = time, format) when format in [:extended, :basic] do
-    %{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    } = time
-
-    Calendar.ISO.time_to_iso8601(hour, minute, second, microsecond, format)
-  end
-
-  def to_iso8601(%{calendar: _} = time, format) when format in [:extended, :basic] do
-    time
-    |> convert!(Calendar.ISO)
-    |> to_iso8601(format)
-  end
-
-  @doc """
-  Converts given `time` to an Erlang time tuple.
-
-  WARNING: Loss of precision may occur, as Erlang time tuples
-  only contain hours/minutes/seconds.
-
-  ## Examples
-
-      iex> Time.to_erl(~T[23:30:15.999])
-      {23, 30, 15}
-
-      iex> Time.to_erl(~N[2010-04-17 23:30:15.999])
-      {23, 30, 15}
-
-  """
-  @spec to_erl(Calendar.time()) :: :calendar.time()
-  def to_erl(time) do
-    %{hour: hour, minute: minute, second: second} = convert!(time, Calendar.ISO)
-    {hour, minute, second}
-  end
-
-  @doc """
-  Converts an Erlang time tuple to a `Time` struct.
-
-  ## Examples
-
-      iex> Time.from_erl({23, 30, 15}, {5000, 3})
-      {:ok, ~T[23:30:15.005]}
-      iex> Time.from_erl({24, 30, 15})
-      {:error, :invalid_time}
-
-  """
-  @spec from_erl(:calendar.time(), Calendar.microsecond(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
-  def from_erl(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO)
-
-  def from_erl({hour, minute, second}, microsecond, calendar) do
-    with {:ok, time} <- new(hour, minute, second, microsecond, Calendar.ISO),
-         do: convert(time, calendar)
-  end
-
-  @doc """
-  Converts an Erlang time tuple to a `Time` struct.
-
-  ## Examples
-
-      iex> Time.from_erl!({23, 30, 15})
-      ~T[23:30:15]
-      iex> Time.from_erl!({23, 30, 15}, {5000, 3})
-      ~T[23:30:15.005]
-      iex> Time.from_erl!({24, 30, 15})
-      ** (ArgumentError) cannot convert {24, 30, 15} to time, reason: :invalid_time
-
-  """
-  @spec from_erl!(:calendar.time(), Calendar.microsecond(), Calendar.calendar()) :: t
-  def from_erl!(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
-    case from_erl(tuple, microsecond, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(tuple)} to time, reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Adds the `number` of `unit`s to the given `time`.
-
-  This function accepts the `number` measured according to `Calendar.ISO`.
-  The time is returned in the same calendar as it was given in.
-
-  Note the result value represents the time of day, meaning that it is cyclic,
-  for instance, it will never go over 24 hours for the ISO calendar.
-
-  ## Examples
-
-      iex> Time.add(~T[10:00:00], 27000)
-      ~T[17:30:00.000000]
-      iex> Time.add(~T[11:00:00.005], 2400)
-      ~T[11:40:00.005000]
-      iex> Time.add(~T[00:00:00], 86_399_999, :millisecond)
-      ~T[23:59:59.999000]
-      iex> Time.add(~T[17:10:05], 86400)
-      ~T[17:10:05.000000]
-      iex> Time.add(~T[23:00:00], -60)
-      ~T[22:59:00.000000]
-
-  """
-  @doc since: "1.6.0"
-  @spec add(Calendar.time(), integer, System.time_unit()) :: t
-  def add(%{calendar: calendar} = time, number, unit \\ :second) when is_integer(number) do
-    number = System.convert_time_unit(number, unit, :microsecond)
-    iso_days = {0, to_day_fraction(time)}
-    total = Calendar.ISO.iso_days_to_unit(iso_days, :microsecond) + number
-    iso_ppd = 86_400_000_000
-    parts = Integer.mod(total, iso_ppd)
-
-    {hour, minute, second, microsecond} = calendar.time_from_day_fraction({parts, iso_ppd})
-
-    %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    }
-  end
-
-  @doc """
-  Compares two time structs.
-
-  Returns `:gt` if first time is later than the second
-  and `:lt` for vice versa. If the two times are equal
-  `:eq` is returned.
-
-  ## Examples
-
-      iex> Time.compare(~T[16:04:16], ~T[16:04:28])
-      :lt
-      iex> Time.compare(~T[16:04:16], ~T[16:04:16])
-      :eq
-      iex> Time.compare(~T[16:04:16.01], ~T[16:04:16.001])
-      :gt
-
-  This function can also be used to compare across more
-  complex calendar types by considering only the time fields:
-
-      iex> Time.compare(~N[1900-01-01 16:04:16], ~N[2015-01-01 16:04:16])
-      :eq
-      iex> Time.compare(~N[2015-01-01 16:04:16], ~N[2015-01-01 16:04:28])
-      :lt
-      iex> Time.compare(~N[2015-01-01 16:04:16.01], ~N[2000-01-01 16:04:16.001])
-      :gt
-
-  """
-  @doc since: "1.4.0"
-  @spec compare(Calendar.time(), Calendar.time()) :: :lt | :eq | :gt
-  def compare(%{calendar: calendar} = time1, %{calendar: calendar} = time2) do
-    %{hour: hour1, minute: minute1, second: second1, microsecond: {microsecond1, _}} = time1
-    %{hour: hour2, minute: minute2, second: second2, microsecond: {microsecond2, _}} = time2
-
-    case {{hour1, minute1, second1, microsecond1}, {hour2, minute2, second2, microsecond2}} do
-      {first, second} when first > second -> :gt
-      {first, second} when first < second -> :lt
-      _ -> :eq
-    end
-  end
-
-  def compare(time1, time2) do
-    {parts1, ppd1} = to_day_fraction(time1)
-    {parts2, ppd2} = to_day_fraction(time2)
-
-    case {parts1 * ppd2, parts2 * ppd1} do
-      {first, second} when first > second -> :gt
-      {first, second} when first < second -> :lt
-      _ -> :eq
-    end
-  end
-
-  @doc """
-  Converts given `time` to a different calendar.
-
-  Returns `{:ok, time}` if the conversion was successful,
-  or `{:error, reason}` if it was not, for some reason.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> Time.convert(~T[13:30:15], Calendar.Holocene)
-      {:ok, %Time{calendar: Calendar.Holocene, hour: 13, minute: 30, second: 15, microsecond: {0, 0}}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert(Calendar.time(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
-
-  # Keep it multiline for proper function clause errors.
-  def convert(
-        %{
-          calendar: calendar,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        },
-        calendar
-      ) do
-    time = %Time{
-      calendar: calendar,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond
-    }
-
-    {:ok, time}
-  end
-
-  def convert(%{microsecond: {_, precision}} = time, calendar) do
-    {hour, minute, second, {microsecond, _}} =
-      time
-      |> to_day_fraction()
-      |> calendar.time_from_day_fraction()
-
-    time = %Time{
-      calendar: calendar,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: {microsecond, precision}
-    }
-
-    {:ok, time}
-  end
-
-  @doc """
-  Similar to `Time.convert/2`, but raises an `ArgumentError`
-  if the conversion between the two calendars is not possible.
-
-  ## Examples
-
-  Imagine someone implements `Calendar.Holocene`, a calendar based on the
-  Gregorian calendar that adds exactly 10,000 years to the current Gregorian
-  year:
-
-      iex> Time.convert!(~T[13:30:15], Calendar.Holocene)
-      %Time{calendar: Calendar.Holocene, hour: 13, minute: 30, second: 15, microsecond: {0, 0}}
-
-  """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.time(), Calendar.calendar()) :: t
-  def convert!(time, calendar) do
-    case convert(time, calendar) do
-      {:ok, value} ->
-        value
-
-      {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(time)} to target calendar #{inspect(calendar)}, " <>
-                "reason: #{inspect(reason)}"
-    end
-  end
-
-  @doc """
-  Returns the difference between two times, considering only the hour, minute,
-  second and microsecond.
-
-  As with the `compare/2` function both `Time` structs and other structures
-  containing time can be used. If for instance a `NaiveDateTime` or `DateTime`
-  is passed, only the hour, month, second, and microsecond is considered. Any
-  additional information about a date or time zone is ignored when calculating
-  the difference.
-
-  The answer can be returned in any `unit` available from
-  `t:System.time_unit/0`. If the first unit is smaller than
-  the second, a negative number is returned.
-
-  This function returns the difference in seconds where seconds
-  are measured according to `Calendar.ISO`.
-
-  ## Examples
-
-      iex> Time.diff(~T[00:29:12], ~T[00:29:10])
-      2
-
-      # When passing a `NaiveDateTime` the date part is ignored.
-      iex> Time.diff(~N[2017-01-01 00:29:12], ~T[00:29:10])
-      2
-
-      # Two `NaiveDateTime` structs could have big differences in the date
-      # but only the time part is considered.
-      iex> Time.diff(~N[2017-01-01 00:29:12], ~N[1900-02-03 00:29:10])
-      2
-
-      iex> Time.diff(~T[00:29:12], ~T[00:29:10], :microsecond)
-      2_000_000
-      iex> Time.diff(~T[00:29:10], ~T[00:29:12], :microsecond)
-      -2_000_000
-
-  """
-  @doc since: "1.5.0"
-  @spec diff(Calendar.time(), Calendar.time(), System.time_unit()) :: integer
-  def diff(time1, time2, unit \\ :second) do
-    fraction1 = to_day_fraction(time1)
-    fraction2 = to_day_fraction(time2)
-
-    Calendar.ISO.iso_days_to_unit({0, fraction1}, unit) -
-      Calendar.ISO.iso_days_to_unit({0, fraction2}, unit)
-  end
-
-  @doc """
-  Returns the given time with the microsecond field truncated to the given
-  precision (`:microsecond`, `millisecond` or `:second`).
-
-  ## Examples
-
-      iex> Time.truncate(~T[01:01:01.123456], :microsecond)
-      ~T[01:01:01.123456]
-
-      iex> Time.truncate(~T[01:01:01.123456], :millisecond)
-      ~T[01:01:01.123]
-
-      iex> Time.truncate(~T[01:01:01.123456], :second)
-      ~T[01:01:01]
-
-  """
-  @doc since: "1.6.0"
-  @spec truncate(t(), :microsecond | :millisecond | :second) :: t()
-  def truncate(%Time{microsecond: microsecond} = time, precision) do
-    %{time | microsecond: Calendar.truncate(microsecond, precision)}
-  end
-
-  ## Helpers
-
-  defp to_day_fraction(%{
-         hour: hour,
-         minute: minute,
-         second: second,
-         microsecond: {_, _} = microsecond,
-         calendar: calendar
-       }) do
-    calendar.time_to_day_fraction(hour, minute, second, microsecond)
-  end
-
-  defimpl String.Chars do
-    def to_string(time) do
-      %{
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond,
-        calendar: calendar
-      } = time
-
-      calendar.time_to_string(hour, minute, second, microsecond)
-    end
-  end
-
-  defimpl Inspect do
-    def inspect(%{calendar: Calendar.ISO} = time, _) do
-      %{
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond,
-        calendar: Calendar.ISO
-      } = time
-
-      "~T[" <> Calendar.ISO.time_to_string(hour, minute, second, microsecond) <> "]"
-    end
-
-    def inspect(time, opts) do
-      Inspect.Any.inspect(time, opts)
-    end
-  end
-end
@@ -1,281 +0,0 @@
-defmodule Code.Identifier do
-  @moduledoc false
-
-  @doc """
-  Checks if the given identifier is an unary op.
-
-  ## Examples
-
-      iex> Code.Identifier.unary_op(:+)
-      {:non_associative, 300}
-
-  """
-  @spec unary_op(atom) :: {:non_associative, precedence :: pos_integer} | :error
-  def unary_op(op) do
-    cond do
-      op in [:&] -> {:non_associative, 90}
-      op in [:!, :^, :not, :+, :-, :~~~] -> {:non_associative, 300}
-      op in [:@] -> {:non_associative, 320}
-      true -> :error
-    end
-  end
-
-  @doc """
-  Checks if the given identifier is a binary op.
-
-  ## Examples
-
-      iex> Code.Identifier.binary_op(:+)
-      {:left, 210}
-
-  """
-  @spec binary_op(atom) :: {:left | :right, precedence :: pos_integer} | :error
-  def binary_op(op) do
-    cond do
-      op in [:<-, :\\] -> {:left, 40}
-      op in [:when] -> {:right, 50}
-      op in [:::] -> {:right, 60}
-      op in [:|] -> {:right, 70}
-      op in [:=] -> {:right, 100}
-      op in [:||, :|||, :or] -> {:left, 130}
-      op in [:&&, :&&&, :and] -> {:left, 140}
-      op in [:==, :!=, :=~, :===, :!==] -> {:left, 150}
-      op in [:<, :<=, :>=, :>] -> {:left, 160}
-      op in [:|>, :<<<, :>>>, :<~, :~>, :<<~, :~>>, :<~>, :<|>] -> {:left, 170}
-      op in [:in] -> {:left, 180}
-      op in [:^^^] -> {:left, 190}
-      op in [:++, :--, :.., :<>] -> {:right, 200}
-      op in [:+, :-] -> {:left, 210}
-      op in [:*, :/] -> {:left, 220}
-      op in [:.] -> {:left, 310}
-      true -> :error
-    end
-  end
-
-  @doc """
-  Classifies the given atom into one of the following categories:
-
-    * `:alias` - a valid Elixir alias, like `Foo`, `Foo.Bar` and so on
-
-    * `:callable_local` - an atom that can be used as a local call;
-      this category includes identifiers like `:foo`
-
-    * `:callable_operators` - all callable operators, such as `:<>`. Note
-      operators such as `:..` are not callable because of ambiguity
-
-    * `:not_callable` - an atom that cannot be used as a function call after the
-      `.` operator (for example, `:<<>>` is not callable because `Foo.<<>>` is a
-      syntax error); this category includes atoms like `:Foo`, since they are
-      valid identifiers but they need quotes to be used in function calls
-      (`Foo."Bar"`)
-
-    * `:other` - any other atom (these are usually escaped when inspected, like
-      `:"foo and bar"`)
-
-  """
-  def classify(atom) when is_atom(atom) do
-    charlist = Atom.to_charlist(atom)
-
-    cond do
-      atom in [:%, :%{}, :{}, :<<>>, :..., :.., :., :->] ->
-        :not_callable
-
-      unary_op(atom) != :error or binary_op(atom) != :error ->
-        :callable_operator
-
-      valid_alias?(charlist) ->
-        :alias
-
-      true ->
-        case :elixir_config.safe_get(:identifier_tokenizer, String.Tokenizer).tokenize(charlist) do
-          {kind, _acc, [], _, _, special} ->
-            if kind == :identifier and not :lists.member(?@, special) do
-              :callable_local
-            else
-              :not_callable
-            end
-
-          _ ->
-            :other
-        end
-    end
-  end
-
-  defp valid_alias?('Elixir' ++ rest), do: valid_alias_piece?(rest)
-  defp valid_alias?(_other), do: false
-
-  defp valid_alias_piece?([?., char | rest]) when char >= ?A and char <= ?Z,
-    do: valid_alias_piece?(trim_leading_while_valid_identifier(rest))
-
-  defp valid_alias_piece?([]), do: true
-  defp valid_alias_piece?(_other), do: false
-
-  defp trim_leading_while_valid_identifier([char | rest])
-       when char >= ?a and char <= ?z
-       when char >= ?A and char <= ?Z
-       when char >= ?0 and char <= ?9
-       when char == ?_ do
-    trim_leading_while_valid_identifier(rest)
-  end
-
-  defp trim_leading_while_valid_identifier(other) do
-    other
-  end
-
-  @doc """
-  Inspects the identifier as an atom.
-  """
-  def inspect_as_atom(atom) when is_nil(atom) or is_boolean(atom) do
-    Atom.to_string(atom)
-  end
-
-  def inspect_as_atom(atom) when is_atom(atom) do
-    binary = Atom.to_string(atom)
-
-    case classify(atom) do
-      :alias ->
-        case binary do
-          binary when binary in ["Elixir", "Elixir.Elixir"] -> binary
-          "Elixir.Elixir." <> _rest -> binary
-          "Elixir." <> rest -> rest
-        end
-
-      type when type in [:callable_local, :callable_operator, :not_callable] ->
-        ":" <> binary
-
-      :other ->
-        {escaped, _} = escape(binary, ?")
-        IO.iodata_to_binary([?:, ?", escaped, ?"])
-    end
-  end
-
-  @doc """
-  Inspects the given identifier as a key.
-  """
-  def inspect_as_key(atom) when is_atom(atom) do
-    binary = Atom.to_string(atom)
-
-    case classify(atom) do
-      type when type in [:callable_local, :callable_operator, :not_callable] ->
-        IO.iodata_to_binary([binary, ?:])
-
-      _ ->
-        {escaped, _} = escape(binary, ?")
-        IO.iodata_to_binary([?", escaped, ?", ?:])
-    end
-  end
-
-  @doc """
-  Inspects the given identifier as a function name.
-  """
-  def inspect_as_function(atom) when is_atom(atom) do
-    binary = Atom.to_string(atom)
-
-    case classify(atom) do
-      type when type in [:callable_local, :callable_operator] ->
-        binary
-
-      type ->
-        escaped =
-          if type in [:not_callable, :alias] do
-            binary
-          else
-            elem(escape(binary, ?"), 0)
-          end
-
-        IO.iodata_to_binary([?", escaped, ?"])
-    end
-  end
-
-  @doc """
-  Extracts the name and arity of the parent from the anonymous function identifier.
-  """
-  # Example of this format: -NAME/ARITY-fun-COUNT-
-  def extract_anonymous_fun_parent(atom) when is_atom(atom) do
-    with "-" <> rest <- Atom.to_string(atom),
-         [trailing | reversed] = rest |> String.split("/") |> Enum.reverse(),
-         [arity, _inner, _count, ""] <- String.split(trailing, "-") do
-      {reversed |> Enum.reverse() |> Enum.join("/") |> String.to_atom(), arity}
-    else
-      _ -> :error
-    end
-  end
-
-  @doc """
-  Escapes the given identifier.
-  """
-  def escape(other, char, count \\ :infinity, fun \\ &escape_map/1) do
-    escape(other, char, count, [], fun)
-  end
-
-  defp escape(<<_, _::binary>> = binary, _char, 0, acc, _fun) do
-    {acc, binary}
-  end
-
-  defp escape(<<char, t::binary>>, char, count, acc, fun) do
-    escape(t, char, decrement(count), [acc | [?\\, char]], fun)
-  end
-
-  defp escape(<<?#, ?{, t::binary>>, char, count, acc, fun) do
-    escape(t, char, decrement(count), [acc | '\\\#{'], fun)
-  end
-
-  defp escape(<<h::utf8, t::binary>>, char, count, acc, fun) do
-    escaped = if value = fun.(h), do: value, else: escape_char(h)
-    escape(t, char, decrement(count), [acc | escaped], fun)
-  end
-
-  defp escape(<<a::4, b::4, t::binary>>, char, count, acc, fun) do
-    escape(t, char, decrement(count), [acc | ['\\x', to_hex(a), to_hex(b)]], fun)
-  end
-
-  defp escape(<<>>, _char, _count, acc, _fun) do
-    {acc, <<>>}
-  end
-
-  defp escape_char(0), do: '\\0'
-
-  defp escape_char(65279), do: '\\uFEFF'
-
-  defp escape_char(char)
-       when char in 0x20..0x7E
-       when char in 0xA0..0xD7FF
-       when char in 0xE000..0xFFFD
-       when char in 0x10000..0x10FFFF do
-    <<char::utf8>>
-  end
-
-  defp escape_char(char) when char < 0x100 do
-    <<a::4, b::4>> = <<char::8>>
-    ['\\x', to_hex(a), to_hex(b)]
-  end
-
-  defp escape_char(char) when char < 0x10000 do
-    <<a::4, b::4, c::4, d::4>> = <<char::16>>
-    ['\\x{', to_hex(a), to_hex(b), to_hex(c), to_hex(d), ?}]
-  end
-
-  defp escape_char(char) when char < 0x1000000 do
-    <<a::4, b::4, c::4, d::4, e::4, f::4>> = <<char::24>>
-    ['\\x{', to_hex(a), to_hex(b), to_hex(c), to_hex(d), to_hex(e), to_hex(f), ?}]
-  end
-
-  defp escape_map(?\a), do: '\\a'
-  defp escape_map(?\b), do: '\\b'
-  defp escape_map(?\d), do: '\\d'
-  defp escape_map(?\e), do: '\\e'
-  defp escape_map(?\f), do: '\\f'
-  defp escape_map(?\n), do: '\\n'
-  defp escape_map(?\r), do: '\\r'
-  defp escape_map(?\t), do: '\\t'
-  defp escape_map(?\v), do: '\\v'
-  defp escape_map(?\\), do: '\\\\'
-  defp escape_map(_), do: false
-
-  @compile {:inline, to_hex: 1, decrement: 1}
-  defp to_hex(c) when c in 0..9, do: ?0 + c
-  defp to_hex(c) when c in 10..15, do: ?A + c - 10
-
-  defp decrement(:infinity), do: :infinity
-  defp decrement(counter), do: counter - 1
-end
@@ -1,430 +0,0 @@
-defmodule Code.Typespec do
-  @moduledoc false
-
-  @doc """
-  Converts a spec clause back to Elixir quoted expression.
-  """
-  @spec spec_to_quoted(atom, tuple) :: {atom, keyword, [Macro.t()]}
-  def spec_to_quoted(name, spec)
-
-  def spec_to_quoted(name, {:type, line, :fun, [{:type, _, :product, args}, result]})
-      when is_atom(name) do
-    meta = [line: line]
-    body = {name, meta, Enum.map(args, &typespec_to_quoted/1)}
-
-    vars =
-      for type_expr <- args ++ [result],
-          var <- collect_vars(type_expr),
-          uniq: true,
-          do: {var, {:var, meta, nil}}
-
-    spec = {:::, meta, [body, typespec_to_quoted(result)]}
-
-    if vars == [] do
-      spec
-    else
-      {:when, meta, [spec, vars]}
-    end
-  end
-
-  def spec_to_quoted(name, {:type, line, :fun, []}) when is_atom(name) do
-    {:::, [line: line], [{name, [line: line], []}, quote(do: term)]}
-  end
-
-  def spec_to_quoted(name, {:type, line, :bounded_fun, [type, constrs]}) when is_atom(name) do
-    {:type, _, :fun, [{:type, _, :product, args}, result]} = type
-
-    guards =
-      for {:type, _, :constraint, [{:atom, _, :is_subtype}, [{:var, _, var}, type]]} <- constrs do
-        {erl_to_ex_var(var), typespec_to_quoted(type)}
-      end
-
-    meta = [line: line]
-    ignore_vars = Keyword.keys(guards)
-
-    vars =
-      for type_expr <- args ++ [result],
-          var <- collect_vars(type_expr),
-          var not in ignore_vars,
-          uniq: true,
-          do: {var, {:var, meta, nil}}
-
-    args = for arg <- args, do: typespec_to_quoted(arg)
-
-    when_args = [
-      {:::, meta, [{name, [line: line], args}, typespec_to_quoted(result)]},
-      guards ++ vars
-    ]
-
-    {:when, meta, when_args}
-  end
-
-  @doc """
-  Converts a type clause back to Elixir AST.
-  """
-  def type_to_quoted(type)
-
-  def type_to_quoted({{:record, record}, fields, args}) when is_atom(record) do
-    fields = for field <- fields, do: typespec_to_quoted(field)
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    type = {:{}, [], [record | fields]}
-    quote(do: unquote(record)(unquote_splicing(args)) :: unquote(type))
-  end
-
-  def type_to_quoted({name, type, args}) when is_atom(name) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    quote(do: unquote(name)(unquote_splicing(args)) :: unquote(typespec_to_quoted(type)))
-  end
-
-  @doc """
-  Returns all types available from the module's BEAM code.
-
-  The result is returned as a list of tuples where the first
-  element is the type (`:typep`, `:type` and `:opaque`).
-
-  The module must have a corresponding BEAM file which can be
-  located by the runtime system. The types will be in the Erlang
-  Abstract Format.
-  """
-  @spec fetch_types(module | binary) :: {:ok, [tuple]} | :error
-  def fetch_types(module) when is_atom(module) or is_binary(module) do
-    case typespecs_abstract_code(module) do
-      {:ok, abstract_code} ->
-        exported_types = for {:attribute, _, :export_type, types} <- abstract_code, do: types
-        exported_types = List.flatten(exported_types)
-
-        types =
-          for {:attribute, _, kind, {name, _, args} = type} <- abstract_code,
-              kind in [:opaque, :type] do
-            cond do
-              kind == :opaque -> {:opaque, type}
-              {name, length(args)} in exported_types -> {:type, type}
-              true -> {:typep, type}
-            end
-          end
-
-        {:ok, types}
-
-      _ ->
-        :error
-    end
-  end
-
-  @doc """
-  Returns all specs available from the module's BEAM code.
-
-  The result is returned as a list of tuples where the first
-  element is spec name and arity and the second is the spec.
-
-  The module must have a corresponding BEAM file which can be
-  located by the runtime system. The types will be in the Erlang
-  Abstract Format.
-  """
-  @spec fetch_specs(module) :: {:ok, [tuple]} | :error
-  def fetch_specs(module) when is_atom(module) or is_binary(module) do
-    case typespecs_abstract_code(module) do
-      {:ok, abstract_code} ->
-        {:ok, for({:attribute, _, :spec, value} <- abstract_code, do: value)}
-
-      :error ->
-        :error
-    end
-  end
-
-  @doc """
-  Returns all callbacks available from the module's BEAM code.
-
-  The result is returned as a list of tuples where the first
-  element is spec name and arity and the second is the spec.
-
-  The module must have a corresponding BEAM file
-  which can be located by the runtime system. The types will be
-  in the Erlang Abstract Format.
-  """
-  @spec fetch_callbacks(module) :: {:ok, [tuple]} | :error
-  def fetch_callbacks(module) when is_atom(module) or is_binary(module) do
-    case typespecs_abstract_code(module) do
-      {:ok, abstract_code} ->
-        {:ok, for({:attribute, _, :callback, value} <- abstract_code, do: value)}
-
-      :error ->
-        :error
-    end
-  end
-
-  # TODO: Do not rely on abstract_code when OTP 20+ support is dropped (v1.8).
-  # We should then be able to simplify this code and use `with`.
-  defp typespecs_abstract_code(module) do
-    case get_module_and_beam(module) do
-      {module, binary} ->
-        case :beam_lib.chunks(binary, [:debug_info]) do
-          {:ok, {_, [debug_info: {:debug_info_v1, backend, data}]}} ->
-            case data do
-              {:elixir_v1, %{}, specs} ->
-                # Fast path to avoid translation to Erlang from Elixir.
-                {:ok, specs}
-
-              _ ->
-                case backend.debug_info(:erlang_v1, module, data, []) do
-                  {:ok, abstract_code} -> {:ok, abstract_code}
-                  _ -> :error
-                end
-            end
-
-          _ ->
-            case :beam_lib.chunks(binary, [:abstract_code]) do
-              {:ok, {_, [{:abstract_code, {_raw_abstract_v1, abstract_code}}]}} ->
-                {:ok, abstract_code}
-
-              _ ->
-                :error
-            end
-        end
-
-      :error ->
-        :error
-    end
-  end
-
-  defp get_module_and_beam(module) when is_atom(module) do
-    case :code.get_object_code(module) do
-      {^module, beam, _filename} -> {module, beam}
-      :error -> :error
-    end
-  end
-
-  defp get_module_and_beam(beam) when is_binary(beam) do
-    case :beam_lib.info(beam) do
-      [_ | _] = info -> {info[:module], beam}
-      _ -> :error
-    end
-  end
-
-  ## To AST conversion
-
-  defp collect_vars({:ann_type, _line, args}) when is_list(args) do
-    []
-  end
-
-  defp collect_vars({:type, _line, _kind, args}) when is_list(args) do
-    Enum.flat_map(args, &collect_vars/1)
-  end
-
-  defp collect_vars({:remote_type, _line, args}) when is_list(args) do
-    Enum.flat_map(args, &collect_vars/1)
-  end
-
-  defp collect_vars({:typed_record_field, _line, type}) do
-    collect_vars(type)
-  end
-
-  defp collect_vars({:paren_type, _line, [type]}) do
-    collect_vars(type)
-  end
-
-  defp collect_vars({:var, _line, var}) do
-    [erl_to_ex_var(var)]
-  end
-
-  defp collect_vars(_) do
-    []
-  end
-
-  defp typespec_to_quoted({:user_type, line, name, args}) do
-    typespec_to_quoted({:type, line, name, args})
-  end
-
-  defp typespec_to_quoted({:type, line, :tuple, :any}) do
-    {:tuple, [line: line], []}
-  end
-
-  defp typespec_to_quoted({:type, line, :tuple, args}) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    {:{}, [line: line], args}
-  end
-
-  defp typespec_to_quoted({:type, _line, :list, [{:type, _, :union, unions} = arg]}) do
-    case unpack_typespec_kw(unions, []) do
-      {:ok, ast} -> ast
-      :error -> [typespec_to_quoted(arg)]
-    end
-  end
-
-  defp typespec_to_quoted({:type, line, :list, []}) do
-    {:list, [line: line], []}
-  end
-
-  defp typespec_to_quoted({:type, _line, :list, [arg]}) do
-    [typespec_to_quoted(arg)]
-  end
-
-  defp typespec_to_quoted({:type, line, :nonempty_list, []}) do
-    [{:..., [line: line], nil}]
-  end
-
-  defp typespec_to_quoted({:type, line, :nonempty_list, [arg]}) do
-    [typespec_to_quoted(arg), {:..., [line: line], nil}]
-  end
-
-  defp typespec_to_quoted({:type, line, :map, :any}) do
-    {:map, [line: line], []}
-  end
-
-  defp typespec_to_quoted({:type, line, :map, fields}) do
-    fields =
-      Enum.map(fields, fn
-        {:type, _, :map_field_assoc, :any} ->
-          {{:optional, [], [{:any, [], []}]}, {:any, [], []}}
-
-        {:type, _, :map_field_exact, [{:atom, _, k}, v]} ->
-          {k, typespec_to_quoted(v)}
-
-        {:type, _, :map_field_exact, [k, v]} ->
-          {{:required, [], [typespec_to_quoted(k)]}, typespec_to_quoted(v)}
-
-        {:type, _, :map_field_assoc, [k, v]} ->
-          {{:optional, [], [typespec_to_quoted(k)]}, typespec_to_quoted(v)}
-      end)
-
-    {struct, fields} = Keyword.pop(fields, :__struct__)
-    map = {:%{}, [line: line], fields}
-
-    if struct do
-      {:%, [line: line], [struct, map]}
-    else
-      map
-    end
-  end
-
-  defp typespec_to_quoted({:type, line, :binary, [arg1, arg2]}) do
-    [arg1, arg2] = for arg <- [arg1, arg2], do: typespec_to_quoted(arg)
-
-    case {typespec_to_quoted(arg1), typespec_to_quoted(arg2)} do
-      {arg1, 0} ->
-        quote(line: line, do: <<_::unquote(arg1)>>)
-
-      {0, arg2} ->
-        quote(line: line, do: <<_::_*unquote(arg2)>>)
-
-      {arg1, arg2} ->
-        quote(line: line, do: <<_::unquote(arg1), _::_*unquote(arg2)>>)
-    end
-  end
-
-  defp typespec_to_quoted({:type, line, :union, args}) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    Enum.reduce(Enum.reverse(args), fn arg, expr -> {:|, [line: line], [arg, expr]} end)
-  end
-
-  defp typespec_to_quoted({:type, line, :fun, [{:type, _, :product, args}, result]}) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    [{:->, [line: line], [args, typespec_to_quoted(result)]}]
-  end
-
-  defp typespec_to_quoted({:type, line, :fun, [args, result]}) do
-    [{:->, [line: line], [[typespec_to_quoted(args)], typespec_to_quoted(result)]}]
-  end
-
-  defp typespec_to_quoted({:type, line, :fun, []}) do
-    typespec_to_quoted({:type, line, :fun, [{:type, line, :any}, {:type, line, :any, []}]})
-  end
-
-  defp typespec_to_quoted({:type, line, :range, [left, right]}) do
-    {:.., [line: line], [typespec_to_quoted(left), typespec_to_quoted(right)]}
-  end
-
-  defp typespec_to_quoted({:type, _line, nil, []}) do
-    []
-  end
-
-  defp typespec_to_quoted({:type, line, name, args}) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    {name, [line: line], args}
-  end
-
-  defp typespec_to_quoted({:var, line, var}) do
-    {erl_to_ex_var(var), line, nil}
-  end
-
-  defp typespec_to_quoted({:op, line, op, arg}) do
-    {op, [line: line], [typespec_to_quoted(arg)]}
-  end
-
-  defp typespec_to_quoted({:remote_type, line, [mod, name, args]}) do
-    remote_type(line, mod, name, args)
-  end
-
-  defp typespec_to_quoted({:ann_type, line, [var, type]}) do
-    {:::, [line: line], [typespec_to_quoted(var), typespec_to_quoted(type)]}
-  end
-
-  defp typespec_to_quoted(
-         {:typed_record_field, {:record_field, line, {:atom, line1, name}}, type}
-       ) do
-    typespec_to_quoted({:ann_type, line, [{:var, line1, name}, type]})
-  end
-
-  defp typespec_to_quoted({:type, _, :any}) do
-    quote(do: ...)
-  end
-
-  defp typespec_to_quoted({:paren_type, _, [type]}) do
-    typespec_to_quoted(type)
-  end
-
-  defp typespec_to_quoted({type, _line, atom}) when is_atom(type) do
-    atom
-  end
-
-  defp typespec_to_quoted(other), do: other
-
-  ## Helpers
-
-  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :charlist}, []) do
-    typespec_to_quoted({:type, line, :charlist, []})
-  end
-
-  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :nonempty_charlist}, []) do
-    typespec_to_quoted({:type, line, :nonempty_charlist, []})
-  end
-
-  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :struct}, []) do
-    typespec_to_quoted({:type, line, :struct, []})
-  end
-
-  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :as_boolean}, [arg]) do
-    typespec_to_quoted({:type, line, :as_boolean, [arg]})
-  end
-
-  defp remote_type(line, {:atom, _, :elixir}, {:atom, _, :keyword}, args) do
-    typespec_to_quoted({:type, line, :keyword, args})
-  end
-
-  defp remote_type(line, mod, name, args) do
-    args = for arg <- args, do: typespec_to_quoted(arg)
-    dot = {:., [line: line], [typespec_to_quoted(mod), typespec_to_quoted(name)]}
-    {dot, [line: line], args}
-  end
-
-  defp erl_to_ex_var(var) do
-    case Atom.to_string(var) do
-      <<"_", c::utf8, rest::binary>> ->
-        String.to_atom("_#{String.downcase(<<c::utf8>>)}#{rest}")
-
-      <<c::utf8, rest::binary>> ->
-        String.to_atom("#{String.downcase(<<c::utf8>>)}#{rest}")
-    end
-  end
-
-  defp unpack_typespec_kw([{:type, _, :tuple, [{:atom, _, atom}, type]} | t], acc) do
-    unpack_typespec_kw(t, [{atom, typespec_to_quoted(type)} | acc])
-  end
-
-  defp unpack_typespec_kw([], acc) do
-    {:ok, Enum.reverse(acc)}
-  end
-
-  defp unpack_typespec_kw(_, _acc) do
-    :error
-  end
-end
@@ -13,7 +13,7 @@ defprotocol Collectable do
  The `Enumerable` protocol is useful to take values out of a collection.
  In order to support a wide range of values, the functions provided by
  the `Enumerable` protocol do not keep shape. For example, passing a
-  map to `Enum.map/2` always returns a list.
+  dictionary to `Enum.map/2` always returns a list.

  This design is intentional. `Enumerable` was designed to support infinite
  collections, resources and other structures with fixed shape. For example,
@@ -24,54 +24,23 @@ defprotocol Collectable do
  `Enumerable` protocol. `into/1` can be seen as the opposite of
  `Enumerable.reduce/3`. If `Enumerable` is about taking values out,
  `Collectable.into/1` is about collecting those values into a structure.
-
-  ## Examples
-
-  To show how to manually use the `Collectable` protocol, let's play with its
-  implementation for `MapSet`.
-
-      iex> {initial_acc, collector_fun} = Collectable.into(MapSet.new())
-      iex> updated_acc = Enum.reduce([1, 2, 3], initial_acc, fn elem, acc ->
-      ...>   collector_fun.(acc, {:cont, elem})
-      ...> end)
-      iex> collector_fun.(updated_acc, :done)
-      #MapSet<[1, 2, 3]>
-
-  To show how the protocol can be implemented, we can take again a look at the
-  implementation for `MapSet`. In this implementation "collecting" elements
-  simply means inserting them in the set through `MapSet.put/2`.
-
-      defimpl Collectable do
-        def into(original) do
-          collector_fun = fn
-            set, {:cont, elem} -> MapSet.put(set, elem)
-            set, :done -> set
-            _set, :halt -> :ok
-          end
-
-          {original, collector_fun}
-        end
-      end
-
  """

  @type command :: {:cont, term} | :done | :halt

  @doc """
-  Returns an initial accumulator and a "collector" function.
+  Returns a function that collects values alongside
+  the initial accumulation value.

-  The returned function receives a term and a command and injects the term into
-  the collectable on every `{:cont, term}` command.
+  The returned function receives a collectable and injects a given
+  value into it for every `{:cont, term}` instruction.

-  `:done` is passed as a command when no further values will be injected. This
-  is useful when there's a need to close resources or normalizing values. A
-  collectable must be returned when the command is `:done`.
+  `:done` is passed when no further values will be injected, useful
+  for closing resources and normalizing values. A collectable must
+  be returned on `:done`.

-  If injection is suddenly interrupted, `:halt` is passed and the function
-  can return any value as it won't be used.
-
-  For examples on how to use the `Collectable` protocol and `into/1` see the
-  module documentation.
+  If injection is suddenly interrupted, `:halt` is passed and it can
+  return any value, as it won't be used.
  """
  @spec into(t) :: {term, (term, command -> t | term)}
  def into(collectable)
@@ -79,65 +48,30 @@ end

 defimpl Collectable, for: List do
  def into(original) do
-    fun = fn
-      list, {:cont, x} -> [x | list]
+    {[], fn
+      list, {:cont, x} -> [x|list]
      list, :done -> original ++ :lists.reverse(list)
      _, :halt -> :ok
-    end
-
-    {[], fun}
+    end}
  end
 end

 defimpl Collectable, for: BitString do
-  def into(original) when is_binary(original) do
-    fun = fn
-      acc, {:cont, x} when is_binary(x) and is_list(acc) ->
-        [acc | x]
-
-      acc, {:cont, x} when is_bitstring(x) and is_bitstring(acc) ->
-        <<acc::bitstring, x::bitstring>>
-
-      acc, {:cont, x} when is_bitstring(x) ->
-        <<IO.iodata_to_binary(acc)::bitstring, x::bitstring>>
-
-      acc, :done when is_bitstring(acc) ->
-        acc
-
-      acc, :done ->
-        IO.iodata_to_binary(acc)
-
-      _, :halt ->
-        :ok
-    end
-
-    {[original], fun}
-  end
-
-  def into(original) when is_bitstring(original) do
-    fun = fn
-      acc, {:cont, x} when is_bitstring(x) ->
-        <<acc::bitstring, x::bitstring>>
-
-      acc, :done ->
-        acc
-
-      _, :halt ->
-        :ok
-    end
-
-    {original, fun}
+  def into(original) do
+    {original, fn
+      acc, {:cont, x} when is_bitstring(x) -> [acc|x]
+      acc, :done -> IO.iodata_to_binary(acc)
+      _, :halt -> :ok
+    end}
  end
 end

 defimpl Collectable, for: Map do
  def into(original) do
-    fun = fn
+    {original, fn
      map, {:cont, {k, v}} -> :maps.put(k, v, map)
      map, :done -> map
      _, :halt -> :ok
-    end
-
-    {original, fun}
+    end}
  end
 end
@@ -1,6 +1,6 @@
 defmodule Dict do
  @moduledoc ~S"""
-  Generic API for dictionaries.
+  WARNING: this module is deprecated.

  If you need a general dictionary, use the `Map` module.
  If you need to manipulate keyword lists, use `Keyword`.
@@ -9,26 +9,50 @@ defmodule Dict do
  `new` function in the respective modules.
  """

-  @moduledoc deprecated: "Use Map or Keyword modules instead"
-
  @type key :: any
  @type value :: any
  @type t :: list | map

-  message =
-    "Use the Map module for working with maps or the Keyword module for working with keyword lists"
+  # TODO: Remove callbacks on 1.3
+  # TODO: Deprecate every function on 1.3
+  @callback new :: t
+  @callback delete(t, key) :: t
+  @callback drop(t, Enum.t) :: t
+  @callback equal?(t, t) :: boolean
+  @callback get(t, key) :: value
+  @callback get(t, key, value) :: value
+  @callback get_lazy(t, key, (() -> value)) :: value
+  @callback get_and_update(t, key, (value -> {value, value})) :: {value, t}
+  @callback fetch(t, key) :: {:ok, value} | :error
+  @callback fetch!(t, key) :: value | no_return
+  @callback has_key?(t, key) :: boolean
+  @callback keys(t) :: [key]
+  @callback merge(t, t) :: t
+  @callback merge(t, t, (key, value, value -> value)) :: t
+  @callback pop(t, key) :: {value, t}
+  @callback pop(t, key, value) :: {value, t}
+  @callback pop_lazy(t, key, (() -> value)) :: {value, t}
+  @callback put(t, key, value) :: t
+  @callback put_new(t, key, value) :: t
+  @callback put_new_lazy(t, key, (() -> value)) :: t
+  @callback size(t) :: non_neg_integer()
+  @callback split(t, Enum.t) :: {t, t}
+  @callback take(t, Enum.t) :: t
+  @callback to_list(t) :: list()
+  @callback update(t, key, value, (value -> value)) :: t
+  @callback update!(t, key, (value -> value)) :: t | no_return
+  @callback values(t) :: list(value)

-  # TODO: Remove by 2.0
-
-  @deprecated message
  defmacro __using__(_) do
    # Use this import to guarantee proper code expansion
    import Kernel, except: [size: 1]

+    %{file: file, line: line} = __CALLER__
+    :elixir_errors.warn(line, file, "the Dict module is deprecated")
+
    quote do
-      message = "Use maps and the Map module instead"
+      @behaviour Dict

-      @deprecated message
      def get(dict, key, default \\ nil) do
        case fetch(dict, key) do
          {:ok, value} -> value
@@ -36,7 +60,6 @@ defmodule Dict do
        end
      end

-      @deprecated message
      def get_lazy(dict, key, fun) when is_function(fun, 0) do
        case fetch(dict, key) do
          {:ok, value} -> value
@@ -44,14 +67,12 @@ defmodule Dict do
        end
      end

-      @deprecated message
      def get_and_update(dict, key, fun) do
        current_value = get(dict, key)
        {get, new_value} = fun.(current_value)
        {get, put(dict, key, new_value)}
      end

-      @deprecated message
      def fetch!(dict, key) do
        case fetch(dict, key) do
          {:ok, value} -> value
@@ -59,35 +80,30 @@ defmodule Dict do
        end
      end

-      @deprecated message
      def has_key?(dict, key) do
-        match?({:ok, _}, fetch(dict, key))
+        match? {:ok, _}, fetch(dict, key)
      end

-      @deprecated message
      def put_new(dict, key, value) do
        case has_key?(dict, key) do
-          true -> dict
+          true  -> dict
          false -> put(dict, key, value)
        end
      end

-      @deprecated message
      def put_new_lazy(dict, key, fun) when is_function(fun, 0) do
        case has_key?(dict, key) do
-          true -> dict
+          true  -> dict
          false -> put(dict, key, fun.())
        end
      end

-      @deprecated message
      def drop(dict, keys) do
        Enum.reduce(keys, dict, &delete(&2, &1))
      end

-      @deprecated message
      def take(dict, keys) do
-        Enum.reduce(keys, new(), fn key, acc ->
+        Enum.reduce(keys, new, fn key, acc ->
          case fetch(dict, key) do
            {:ok, value} -> put(acc, key, value)
            :error -> acc
@@ -95,49 +111,41 @@ defmodule Dict do
        end)
      end

-      @deprecated message
      def to_list(dict) do
-        reduce(dict, {:cont, []}, fn kv, acc -> {:cont, [kv | acc]} end)
-        |> elem(1)
-        |> :lists.reverse()
+        reduce(dict, {:cont, []}, fn
+          kv, acc -> {:cont, [kv|acc]}
+        end) |> elem(1) |> :lists.reverse
      end

-      @deprecated message
      def keys(dict) do
-        reduce(dict, {:cont, []}, fn {k, _}, acc -> {:cont, [k | acc]} end)
-        |> elem(1)
-        |> :lists.reverse()
+        reduce(dict, {:cont, []}, fn
+          {k, _}, acc -> {:cont, [k|acc]}
+        end) |> elem(1) |> :lists.reverse
      end

-      @deprecated message
      def values(dict) do
-        reduce(dict, {:cont, []}, fn {_, v}, acc -> {:cont, [v | acc]} end)
-        |> elem(1)
-        |> :lists.reverse()
+        reduce(dict, {:cont, []}, fn
+          {_, v}, acc -> {:cont, [v|acc]}
+        end) |> elem(1) |> :lists.reverse
      end

-      @deprecated message
      def equal?(dict1, dict2) do
        # Use this import to avoid conflicts in the user code
        import Kernel, except: [size: 1]

        case size(dict1) == size(dict2) do
-          false ->
-            false
-
-          true ->
-            reduce(dict1, {:cont, true}, fn {k, v}, _acc ->
+          false -> false
+          true  ->
+            reduce(dict1, {:cont, true}, fn({k, v}, _acc) ->
              case fetch(dict2, k) do
                {:ok, ^v} -> {:cont, true}
                _ -> {:halt, false}
              end
-            end)
-            |> elem(1)
+            end) |> elem(1)
        end
      end

-      @deprecated message
-      def merge(dict1, dict2, fun \\ fn _k, _v1, v2 -> v2 end) do
+      def merge(dict1, dict2, fun \\ fn(_k, _v1, v2) -> v2 end) do
        # Use this import to avoid conflicts in the user code
        import Kernel, except: [size: 1]

@@ -149,182 +157,144 @@ defmodule Dict do
          reduce(dict2, {:cont, dict1}, fn {k, v2}, acc ->
            {:cont, update(acc, k, v2, &fun.(k, &1, v2))}
          end)
-        end
-        |> elem(1)
+        end |> elem(1)
      end

-      @deprecated message
      def update(dict, key, initial, fun) do
        case fetch(dict, key) do
          {:ok, value} ->
            put(dict, key, fun.(value))
-
          :error ->
            put(dict, key, initial)
        end
      end

-      @deprecated message
      def update!(dict, key, fun) do
        case fetch(dict, key) do
          {:ok, value} ->
            put(dict, key, fun.(value))
-
          :error ->
            raise KeyError, key: key, term: dict
        end
      end

-      @deprecated message
      def pop(dict, key, default \\ nil) do
        case fetch(dict, key) do
          {:ok, value} ->
            {value, delete(dict, key)}
-
          :error ->
            {default, dict}
        end
      end

-      @deprecated message
      def pop_lazy(dict, key, fun) when is_function(fun, 0) do
        case fetch(dict, key) do
          {:ok, value} ->
            {value, delete(dict, key)}
-
          :error ->
            {fun.(), dict}
        end
      end

-      @deprecated message
      def split(dict, keys) do
-        Enum.reduce(keys, {new(), dict}, fn key, {inc, exc} = acc ->
+        Enum.reduce(keys, {new, dict}, fn key, {inc, exc} = acc ->
          case fetch(exc, key) do
            {:ok, value} ->
              {put(inc, key, value), delete(exc, key)}
-
            :error ->
              acc
          end
        end)
      end

-      defoverridable merge: 2,
-                     merge: 3,
-                     equal?: 2,
-                     to_list: 1,
-                     keys: 1,
-                     values: 1,
-                     take: 2,
-                     drop: 2,
-                     get: 2,
-                     get: 3,
-                     fetch!: 2,
-                     has_key?: 2,
-                     put_new: 3,
-                     pop: 2,
-                     pop: 3,
-                     split: 2,
-                     update: 4,
-                     update!: 3,
-                     get_and_update: 3,
-                     get_lazy: 3,
-                     pop_lazy: 3,
-                     put_new_lazy: 3
+      defoverridable merge: 2, merge: 3, equal?: 2, to_list: 1, keys: 1,
+                     values: 1, take: 2, drop: 2, get: 2, get: 3, fetch!: 2,
+                     has_key?: 2, put_new: 3, pop: 2, pop: 3, split: 2,
+                     update: 4, update!: 3, get_and_update: 3, get_lazy: 3,
+                     pop_lazy: 3, put_new_lazy: 3
    end
  end

  defmacrop target(dict) do
    quote do
      case unquote(dict) do
-        %module{} -> module
-        %{} -> Map
-        dict when is_list(dict) -> Keyword
-        dict -> unsupported_dict(dict)
+        %{__struct__: x} when is_atom(x) ->
+          x
+        %{} ->
+          Map
+        x when is_list(x) ->
+          Keyword
+        x ->
+          unsupported_dict(x)
      end
    end
  end

-  @deprecated message
  @spec keys(t) :: [key]
  def keys(dict) do
    target(dict).keys(dict)
  end

-  @deprecated message
  @spec values(t) :: [value]
  def values(dict) do
    target(dict).values(dict)
  end

-  @deprecated message
  @spec size(t) :: non_neg_integer
  def size(dict) do
    target(dict).size(dict)
  end

-  @deprecated message
  @spec has_key?(t, key) :: boolean
  def has_key?(dict, key) do
    target(dict).has_key?(dict, key)
  end

-  @deprecated message
  @spec get(t, key, value) :: value
  def get(dict, key, default \\ nil) do
    target(dict).get(dict, key, default)
  end

-  @deprecated message
  @spec get_lazy(t, key, (() -> value)) :: value
  def get_lazy(dict, key, fun) do
    target(dict).get_lazy(dict, key, fun)
  end

-  @deprecated message
  @spec get_and_update(t, key, (value -> {value, value})) :: {value, t}
  def get_and_update(dict, key, fun) do
    target(dict).get_and_update(dict, key, fun)
  end

-  @deprecated message
  @spec fetch(t, key) :: value
  def fetch(dict, key) do
    target(dict).fetch(dict, key)
  end

-  @deprecated message
  @spec fetch!(t, key) :: value | no_return
  def fetch!(dict, key) do
    target(dict).fetch!(dict, key)
  end

-  @deprecated message
  @spec put(t, key, value) :: t
  def put(dict, key, val) do
    target(dict).put(dict, key, val)
  end

-  @deprecated message
  @spec put_new(t, key, value) :: t
  def put_new(dict, key, val) do
    target(dict).put_new(dict, key, val)
  end

-  @deprecated message
  @spec put_new_lazy(t, key, (() -> value)) :: t
  def put_new_lazy(dict, key, fun) do
    target(dict).put_new_lazy(dict, key, fun)
  end

-  @deprecated message
  @spec delete(t, key) :: t
  def delete(dict, key) do
    target(dict).delete(dict, key)
  end

-  @deprecated message
  @spec merge(t, t) :: t
  def merge(dict1, dict2) do
    target1 = target(dict1)
@@ -333,11 +303,10 @@ defmodule Dict do
    if target1 == target2 do
      target1.merge(dict1, dict2)
    else
-      do_merge(target1, dict1, dict2, fn _k, _v1, v2 -> v2 end)
+      do_merge(target1, dict1, dict2, fn(_k, _v1, v2) -> v2 end)
    end
  end

-  @deprecated message
  @spec merge(t, t, (key, value, value -> value)) :: t
  def merge(dict1, dict2, fun) do
    target1 = target(dict1)
@@ -351,61 +320,51 @@ defmodule Dict do
  end

  defp do_merge(target1, dict1, dict2, fun) do
-    Enumerable.reduce(dict2, {:cont, dict1}, fn {k, v}, acc ->
-      {:cont, target1.update(acc, k, v, fn other -> fun.(k, other, v) end)}
-    end)
-    |> elem(1)
+    Enumerable.reduce(dict2, {:cont, dict1}, fn({k, v}, acc) ->
+      {:cont, target1.update(acc, k, v, fn(other) -> fun.(k, other, v) end)}
+    end) |> elem(1)
  end

-  @deprecated message
  @spec pop(t, key, value) :: {value, t}
  def pop(dict, key, default \\ nil) do
    target(dict).pop(dict, key, default)
  end

-  @deprecated message
  @spec pop_lazy(t, key, (() -> value)) :: {value, t}
  def pop_lazy(dict, key, fun) do
    target(dict).pop_lazy(dict, key, fun)
  end

-  @deprecated message
  @spec update!(t, key, (value -> value)) :: t
  def update!(dict, key, fun) do
    target(dict).update!(dict, key, fun)
  end

-  @deprecated message
  @spec update(t, key, value, (value -> value)) :: t
  def update(dict, key, initial, fun) do
    target(dict).update(dict, key, initial, fun)
  end

-  @deprecated message
  @spec split(t, [key]) :: {t, t}
  def split(dict, keys) do
    target(dict).split(dict, keys)
  end

-  @deprecated message
  @spec drop(t, [key]) :: t
  def drop(dict, keys) do
    target(dict).drop(dict, keys)
  end

-  @deprecated message
  @spec take(t, [key]) :: t
  def take(dict, keys) do
    target(dict).take(dict, keys)
  end

-  @deprecated message
  @spec empty(t) :: t
  def empty(dict) do
    target(dict).empty(dict)
  end

-  @deprecated message
  @spec equal?(t, t) :: boolean
  def equal?(dict1, dict2) do
    target1 = target(dict1)
@@ -416,27 +375,24 @@ defmodule Dict do
        target1.equal?(dict1, dict2)

      target1.size(dict1) == target2.size(dict2) ->
-        Enumerable.reduce(dict2, {:cont, true}, fn {k, v}, _acc ->
+        Enumerable.reduce(dict2, {:cont, true}, fn({k, v}, _acc) ->
          case target1.fetch(dict1, k) do
            {:ok, ^v} -> {:cont, true}
-            _ -> {:halt, false}
+            _         -> {:halt, false}
          end
-        end)
-        |> elem(1)
+        end) |> elem(1)

      true ->
        false
    end
  end

-  @deprecated message
  @spec to_list(t) :: list
  def to_list(dict) do
    target(dict).to_list(dict)
  end

-  @spec unsupported_dict(t) :: no_return
  defp unsupported_dict(dict) do
-    raise ArgumentError, "unsupported dict: #{inspect(dict)}"
+    raise ArgumentError, "unsupported dict: #{inspect dict}"
  end
 end
@@ -32,7 +32,7 @@ defmodule File.Stat do
      systems which have no concept of links.

    * `major_device` - identifies the file system where the file is located.
-      In Windows, the number indicates a drive as follows: 0 means A:, 1 means
+      In windows, the number indicates a drive as follows: 0 means A:, 1 means
      B:, and so on.

    * `minor_device` - only valid for character devices on Unix. In all other
@@ -53,9 +53,9 @@ defmodule File.Stat do
  """

  record = Record.extract(:file_info, from_lib: "kernel/include/file.hrl")
-  keys = :lists.map(&elem(&1, 0), record)
-  vals = :lists.map(&{&1, [], nil}, keys)
-  pairs = :lists.zip(keys, vals)
+  keys   = :lists.map(&elem(&1, 0), record)
+  vals   = :lists.map(&{&1, [], nil}, keys)
+  pairs  = :lists.zip(keys, vals)

  defstruct keys
  @type t :: %__MODULE__{}
@@ -71,7 +71,6 @@ defmodule File.Stat do
  Converts a `:file_info` record into a `File.Stat`.
  """
  def from_record(file_info)
-
  def from_record({:file_info, unquote_splicing(vals)}) do
    %File.Stat{unquote_splicing(pairs)}
  end
@@ -7,7 +7,7 @@ defmodule File.Stream do
    * `path`          - the file path
    * `modes`         - the file modes
    * `raw`           - a boolean indicating if bin functions should be used
-    * `line_or_bytes` - if reading should read lines or a given number of bytes
+    * `line_or_bytes` - if reading should read lines or a given amount of bytes

  """

@@ -22,12 +22,11 @@ defmodule File.Stream do
    modes =
      case raw do
        true ->
-          case :lists.keyfind(:read_ahead, 1, modes) do
-            {:read_ahead, false} -> [:raw | :lists.keydelete(:read_ahead, 1, modes)]
-            {:read_ahead, _} -> [:raw | modes]
-            false -> [:raw, :read_ahead | modes]
+          if :lists.keyfind(:read_ahead, 1, modes) == {:read_ahead, false} do
+            [:raw | modes]
+          else
+            [:raw, :read_ahead | modes]
          end
-
        false ->
          modes
      end
@@ -37,12 +36,11 @@ defmodule File.Stream do

  defimpl Collectable do
    def into(%{path: path, modes: modes, raw: raw} = stream) do
-      modes = for mode <- modes, mode not in [:read], do: mode
+      modes = for mode <- modes, not mode in [:read], do: mode

-      case :file.open(path, [:write | modes]) do
+      case :file.open(path, [:write|modes]) do
        {:ok, device} ->
          {:ok, into(device, stream, raw)}
-
        {:error, reason} ->
          raise File.Error, reason: reason, action: "stream", path: path
      end
@@ -52,16 +50,14 @@ defmodule File.Stream do
      fn
        :ok, {:cont, x} ->
          case raw do
-            true -> IO.binwrite(device, x)
+            true  -> IO.binwrite(device, x)
            false -> IO.write(device, x)
          end
-
        :ok, :done ->
          # If delayed_write option is used and the last write failed will
          # MatchError here as {:error, _} is returned.
          :ok = :file.close(device)
          stream
-
        :ok, :halt ->
          # If delayed_write option is used and the last write failed will
          # MatchError here as {:error, _} is returned.
@@ -71,55 +67,27 @@ defmodule File.Stream do
  end

  defimpl Enumerable do
-    @read_ahead_size 64 * 1024
-
    def reduce(%{path: path, modes: modes, line_or_bytes: line_or_bytes, raw: raw}, acc, fun) do
-      start_fun = fn ->
-        case :file.open(path, read_modes(modes)) do
-          {:ok, device} ->
-            if :trim_bom in modes, do: trim_bom(device, raw) |> elem(0), else: device
+      modes = for mode <- modes, not mode in [:write, :append], do: mode

-          {:error, reason} ->
-            raise File.Error, reason: reason, action: "stream", path: path
+      start_fun =
+        fn ->
+          case :file.open(path, modes) do
+            {:ok, device}    -> device
+            {:error, reason} ->
+              raise File.Error, reason: reason, action: "stream", path: path
+          end
        end
-      end

      next_fun =
        case raw do
-          true -> &IO.each_binstream(&1, line_or_bytes)
+          true  -> &IO.each_binstream(&1, line_or_bytes)
          false -> &IO.each_stream(&1, line_or_bytes)
        end

      Stream.resource(start_fun, next_fun, &:file.close/1).(acc, fun)
    end

-    def count(%{path: path, modes: modes, line_or_bytes: :line} = stream) do
-      pattern = :binary.compile_pattern("\n")
-      counter = &count_lines(&1, path, pattern, read_function(stream), 0)
-
-      case File.open(path, read_modes(modes), counter) do
-        {:ok, count} ->
-          {:ok, count}
-
-        {:error, reason} ->
-          raise File.Error, reason: reason, action: "stream", path: path
-      end
-    end
-
-    def count(%{path: path, line_or_bytes: bytes, raw: true, modes: modes}) do
-      case File.stat(path) do
-        {:ok, %{size: 0}} ->
-          {:error, __MODULE__}
-
-        {:ok, %{size: size}} ->
-          remainder = if rem(size, bytes) == 0, do: 0, else: 1
-          {:ok, div(size, bytes) + remainder - count_raw_bom(path, modes)}
-
-        {:error, reason} ->
-          raise File.Error, reason: reason, action: "stream", path: path
-      end
-    end
-
    def count(_stream) do
      {:error, __MODULE__}
    end
@@ -127,64 +95,5 @@ defmodule File.Stream do
    def member?(_stream, _term) do
      {:error, __MODULE__}
    end
-
-    def slice(_stream) do
-      {:error, __MODULE__}
-    end
-
-    defp count_raw_bom(path, modes) do
-      if :trim_bom in modes do
-        File.open!(path, read_modes(modes), &(&1 |> trim_bom(true) |> elem(1)))
-      else
-        0
-      end
-    end
-
-    defp trim_bom(device, true) do
-      bom_length = device |> IO.binread(4) |> bom_length()
-      {:ok, new_pos} = :file.position(device, bom_length)
-      {device, new_pos}
-    end
-
-    defp trim_bom(device, false) do
-      # Or we read the bom in the correct amount or it isn't there
-      case bom_length(IO.read(device, 1)) do
-        0 ->
-          {:ok, _} = :file.position(device, 0)
-          {device, 0}
-
-        _ ->
-          {device, 1}
-      end
-    end
-
-    defp bom_length(<<239, 187, 191, _rest::binary>>), do: 3
-    defp bom_length(<<254, 255, _rest::binary>>), do: 2
-    defp bom_length(<<255, 254, _rest::binary>>), do: 2
-    defp bom_length(<<0, 0, 254, 255, _rest::binary>>), do: 4
-    defp bom_length(<<254, 255, 0, 0, _rest::binary>>), do: 4
-    defp bom_length(_binary), do: 0
-
-    defp read_modes(modes) do
-      for mode <- modes, mode not in [:write, :append, :trim_bom], do: mode
-    end
-
-    defp count_lines(device, path, pattern, read, count) do
-      case read.(device) do
-        data when is_binary(data) ->
-          count_lines(device, path, pattern, read, count + count_lines(data, pattern))
-
-        :eof ->
-          count
-
-        {:error, reason} ->
-          raise File.Error, reason: reason, action: "stream", path: path
-      end
-    end
-
-    defp count_lines(data, pattern), do: length(:binary.matches(data, pattern))
-
-    defp read_function(%{raw: true}), do: &IO.binread(&1, @read_ahead_size)
-    defp read_function(%{raw: false}), do: &IO.read(&1, @read_ahead_size)
  end
 end
@@ -2,69 +2,30 @@ import Kernel, except: [round: 1]

 defmodule Float do
  @moduledoc """
-  Functions for working with floating-point numbers.
-
-  ## Kernel functions
-
-  There are functions related to floating-point numbers on the `Kernel` module
-  too. Here is a list of them:
-
-    * `Kernel.round/1`: rounds a number to the nearest integer.
-    * `Kernel.trunc/1`: returns the integer part of a number.
-
-  ## Known issues
-
-  There are some very well known problems with floating-point numbers
-  and arithmetics due to the fact most decimal fractions cannot be
-  represented by a floating-point binary and most operations are not exact,
-  but operate on approximations. Those issues are not specific
-  to Elixir, they are a property of floating point representation itself.
-
-  For example, the numbers 0.1 and 0.01 are two of them, what means the result
-  of squaring 0.1 does not give 0.01 neither the closest representable. Here is
-  what happens in this case:
-
-    * The closest representable number to 0.1 is 0.1000000014
-    * The closest representable number to 0.01 is 0.0099999997
-    * Doing 0.1 * 0.1 should return 0.01, but because 0.1 is actually 0.1000000014,
-      the result is 0.010000000000000002, and because this is not the closest
-      representable number to 0.01, you'll get the wrong result for this operation
-
-  There are also other known problems like flooring or rounding numbers. See
-  `round/2` and `floor/2` for more details about them.
-
-  To learn more about floating-point arithmetic visit:
-
-    * [0.30000000000000004.com](http://0.30000000000000004.com/)
-    * [What Every Programmer Should Know About Floating-Point Arithmetic](http://floating-point-gui.de/)
-
+  Functions for working with floating point numbers.
  """

-  import Bitwise
-
-  @power_of_2_to_52 4_503_599_627_370_496
-  @precision_range 0..15
-  @type precision_range :: 0..15
-
  @doc """
  Parses a binary into a float.

-  If successful, returns a tuple in the form of `{float, remainder_of_binary}`;
+  If successful, returns a tuple of the form `{float, remainder_of_binary}`;
  when the binary cannot be coerced into a valid float, the atom `:error` is
  returned.

  If the size of float exceeds the maximum size of `1.7976931348623157e+308`,
  the `ArgumentError` exception is raised.

-  If you want to convert a string-formatted float directly to a float,
+  If a float formatted string wants to be directly converted to a float,
  `String.to_float/1` can be used instead.

  ## Examples

      iex> Float.parse("34")
      {34.0, ""}
+
      iex> Float.parse("34.25")
      {34.25, ""}
+
      iex> Float.parse("56.5xyz")
      {56.5, "xyz"}

@@ -88,94 +49,66 @@ defmodule Float do
    parse_unsigned(binary)
  end

-  defp parse_unsigned(<<digit, rest::binary>>) when digit in ?0..?9,
-    do: parse_unsigned(rest, false, false, <<digit>>)
+  defp parse_unsigned(<<digit, rest::binary>>) when digit in ?0..?9, do:
+    parse_unsigned(rest, false, false, <<digit>>)

-  defp parse_unsigned(binary) when is_binary(binary), do: :error
+  defp parse_unsigned(binary) when is_binary(binary), do:
+    :error

-  defp parse_unsigned(<<digit, rest::binary>>, dot?, e?, acc) when digit in ?0..?9,
-    do: parse_unsigned(rest, dot?, e?, <<acc::binary, digit>>)
+  defp parse_unsigned(<<digit, rest::binary>>, dot?, e?, acc) when digit in ?0..?9, do:
+    parse_unsigned(rest, dot?, e?, <<acc::binary, digit>>)

-  defp parse_unsigned(<<?., digit, rest::binary>>, false, false, acc) when digit in ?0..?9,
-    do: parse_unsigned(rest, true, false, <<acc::binary, ?., digit>>)
+  defp parse_unsigned(<<?., digit, rest::binary>>, false, false, acc) when digit in ?0..?9, do:
+    parse_unsigned(rest, true, false, <<acc::binary, ?., digit>>)

-  defp parse_unsigned(<<exp_marker, digit, rest::binary>>, dot?, false, acc)
-       when exp_marker in 'eE' and digit in ?0..?9,
-       do: parse_unsigned(rest, true, true, <<add_dot(acc, dot?)::binary, ?e, digit>>)
+  defp parse_unsigned(<<exp_marker, digit, rest::binary>>, dot?, false, acc) when exp_marker in 'eE' and  digit in ?0..?9, do:
+    parse_unsigned(rest, true, true, <<add_dot(acc, dot?)::binary, ?e, digit>>)

-  defp parse_unsigned(<<exp_marker, sign, digit, rest::binary>>, dot?, false, acc)
-       when exp_marker in 'eE' and sign in '-+' and digit in ?0..?9,
-       do: parse_unsigned(rest, true, true, <<add_dot(acc, dot?)::binary, ?e, sign, digit>>)
+  defp parse_unsigned(<<exp_marker, sign, digit, rest::binary>>, dot?, false, acc) when exp_marker in 'eE' and sign in '-+' and digit in ?0..?9, do:
+    parse_unsigned(rest, true, true, <<add_dot(acc, dot?)::binary, ?e, sign, digit>>)

-  defp parse_unsigned(rest, dot?, _e?, acc),
-    do: {:erlang.binary_to_float(add_dot(acc, dot?)), rest}
+  defp parse_unsigned(rest, dot?, _e?, acc), do:
+    {:erlang.binary_to_float(add_dot(acc, dot?)), rest}

-  defp add_dot(acc, true), do: acc
+  defp add_dot(acc, true),  do: acc
  defp add_dot(acc, false), do: acc <> ".0"

  @doc """
-  Rounds a float to the largest number less than or equal to `num`.
+  Rounds a float to the largest integer less than or equal to `num`.

-  `floor/2` also accepts a precision to round a floating-point value down
+  `floor/2` also accepts a precision to round a floating point value down
  to an arbitrary number of fractional digits (between 0 and 15).
-  The operation is performed on the binary floating point, without a
-  conversion to decimal.

  This function always returns a float. `Kernel.trunc/1` may be used instead to
  truncate the result to an integer afterwards.

-  ## Known issues
-
-  The behaviour of `floor/2` for floats can be surprising. For example:
-
-      iex> Float.floor(12.52, 2)
-      12.51
-
-  One may have expected it to floor to 12.52. This is not a bug.
-  Most decimal fractions cannot be represented as a binary floating point
-  and therefore the number above is internally represented as 12.51999999,
-  which explains the behaviour above.
-
  ## Examples

      iex> Float.floor(34.25)
      34.0
+
      iex> Float.floor(-56.5)
      -57.0
+
      iex> Float.floor(34.259, 2)
      34.25

  """
-  @spec floor(float, precision_range) :: float
-  def floor(number, precision \\ 0)
-
-  def floor(number, precision) when is_float(number) and precision in @precision_range do
-    round(number, precision, :floor)
-  end
-
-  def floor(number, precision) when is_float(number) do
-    raise ArgumentError, invalid_precision_message(precision)
+  @spec floor(float, 0..15) :: float
+  def floor(number, precision \\ 0) when is_float(number) and precision in 0..15 do
+    power     = power_of_10(precision)
+    number    = number * power
+    truncated = trunc(number)
+    variance  = if number - truncated < 0, do: -1.0, else: 0.0
+    (truncated + variance) / power
  end

  @doc """
  Rounds a float to the smallest integer greater than or equal to `num`.

-  `ceil/2` also accepts a precision to round a floating-point value down
+  `ceil/2` also accepts a precision to round a floating point value down
  to an arbitrary number of fractional digits (between 0 and 15).

-  The operation is performed on the binary floating point, without a
-  conversion to decimal.
-
-  The behaviour of `ceil/2` for floats can be surprising. For example:
-
-      iex> Float.ceil(-12.52, 2)
-      -12.51
-
-  One may have expected it to ceil to -12.52. This is not a bug.
-  Most decimal fractions cannot be represented as a binary floating point
-  and therefore the number above is internally represented as -12.51999999,
-  which explains the behaviour above.
-
  This function always returns floats. `Kernel.trunc/1` may be used instead to
  truncate the result to an integer afterwards.

@@ -183,321 +116,136 @@ defmodule Float do

      iex> Float.ceil(34.25)
      35.0
+
      iex> Float.ceil(-56.5)
      -56.0
+
      iex> Float.ceil(34.251, 2)
      34.26

  """
-  @spec ceil(float, precision_range) :: float
-  def ceil(number, precision \\ 0)
-
-  def ceil(number, precision) when is_float(number) and precision in @precision_range do
-    round(number, precision, :ceil)
-  end
-
-  def ceil(number, precision) when is_float(number) do
-    raise ArgumentError, invalid_precision_message(precision)
+  @spec ceil(float, 0..15) :: float
+  def ceil(number, precision \\ 0) when is_float(number) and precision in 0..15 do
+    power     = power_of_10(precision)
+    number    = number * power
+    truncated = trunc(number)
+    variance  = if number - truncated > 0, do: 1.0, else: 0.0
+    (truncated + variance) / power
  end

  @doc """
-  Rounds a floating-point value to an arbitrary number of fractional
-  digits (between 0 and 15).
-
-  The rounding direction always ties to half up. The operation is
-  performed on the binary floating point, without a conversion to decimal.
+  Rounds a floating point value to an arbitrary number of fractional digits
+  (between 0 and 15).

  This function only accepts floats and always returns a float. Use
-  `Kernel.round/1` if you want a function that accepts both floats
-  and integers and always returns an integer.
-
-  ## Known issues
-
-  The behaviour of `round/2` for floats can be surprising. For example:
-
-      iex> Float.round(5.5675, 3)
-      5.567
-
-  One may have expected it to round to the half up 5.568. This is not a bug.
-  Most decimal fractions cannot be represented as a binary floating point
-  and therefore the number above is internally represented as 5.567499999,
-  which explains the behaviour above. If you want exact rounding for decimals,
-  you must use a decimal library. The behaviour above is also in accordance
-  to reference implementations, such as "Correctly Rounded Binary-Decimal and
-  Decimal-Binary Conversions" by David M. Gay.
+  `Kernel.round/1` if you want a function that accepts both floats and integers
+  and always returns an integer.

  ## Examples

-      iex> Float.round(12.5)
-      13.0
      iex> Float.round(5.5674, 3)
      5.567
+
      iex> Float.round(5.5675, 3)
-      5.567
+      5.568
+
      iex> Float.round(-5.5674, 3)
      -5.567
-      iex> Float.round(-5.5675)
-      -6.0
-      iex> Float.round(12.341444444444441, 15)
-      12.341444444444441
+
+      iex> Float.round(-5.5675, 3)
+      -5.568

  """
-  @spec round(float, precision_range) :: float
-  # This implementation is slow since it relies on big integers.
-  # Faster implementations are available on more recent papers
-  # and could be implemented in the future.
-  def round(float, precision \\ 0)
-
-  def round(float, precision) when is_float(float) and precision in @precision_range do
-    round(float, precision, :half_up)
+  @spec round(float, 0..15) :: float
+  def round(number, precision \\ 0) when is_float(number) and precision in 0..15 do
+    power = power_of_10(precision)
+    Kernel.round(number * power) / power
  end

-  def round(number, precision) when is_float(number) do
-    raise ArgumentError, invalid_precision_message(precision)
-  end
-
-  defp round(float, precision, rounding) do
-    <<sign::1, exp::11, significant::52-bitstring>> = <<float::float>>
-    {num, count, _} = decompose(significant)
-    count = count - exp + 1023
-
-    cond do
-      # There is no decimal precision
-      # zero or minus zero
-      count <= 0 or (0 == exp and <<0::52>> == significant) ->
-        float
-
-      # Precision beyond 15 digits
-      count >= 104 ->
-        case rounding do
-          :ceil when sign === 0 -> 1 / power_of_10(precision)
-          :floor when sign === 1 -> -1 / power_of_10(precision)
-          _ -> 0.0
-        end
-
-      # We are asking more precision than we have
-      count <= precision ->
-        float
-
-      true ->
-        # Difference in precision between float and asked precision
-        # We subtract 1 because we need to calculate the remainder too
-        diff = count - precision - 1
-
-        # Get up to latest so we calculate the remainder
-        power_of_10 = power_of_10(diff)
-
-        # Convert the numerand to decimal base
-        num = num * power_of_5(count)
-
-        # Move to the given precision - 1
-        num = div(num, power_of_10)
-        div = div(num, 10)
-        num = rounding(rounding, sign, num, div)
-
-        # Convert back to float without loss
-        # http://www.exploringbinary.com/correct-decimal-to-floating-point-using-big-integers/
-        den = power_of_10(precision)
-        boundary = den <<< 52
-
-        cond do
-          num == 0 ->
-            0.0
-
-          num >= boundary ->
-            {den, exp} = scale_down(num, boundary, 52)
-            decimal_to_float(sign, num, den, exp)
-
-          true ->
-            {num, exp} = scale_up(num, boundary, 52)
-            decimal_to_float(sign, num, den, exp)
-        end
-    end
-  end
-
-  defp scale_up(num, boundary, exp) when num >= boundary, do: {num, exp}
-  defp scale_up(num, boundary, exp), do: scale_up(num <<< 1, boundary, exp - 1)
-
-  defp scale_down(num, den, exp) do
-    new_den = den <<< 1
-
-    if num < new_den do
-      {den >>> 52, exp}
-    else
-      scale_down(num, new_den, exp + 1)
-    end
-  end
-
-  defp decimal_to_float(sign, num, den, exp) do
-    quo = div(num, den)
-    rem = num - quo * den
-
-    tmp =
-      case den >>> 1 do
-        den when rem > den -> quo + 1
-        den when rem < den -> quo
-        _ when (quo &&& 1) === 1 -> quo + 1
-        _ -> quo
-      end
-
-    tmp = tmp - @power_of_2_to_52
-    <<tmp::float>> = <<sign::1, exp + 1023::11, tmp::52>>
-    tmp
-  end
-
-  defp rounding(:floor, 1, _num, div), do: div + 1
-  defp rounding(:ceil, 0, _num, div), do: div + 1
-
-  defp rounding(:half_up, _sign, num, div) do
-    case rem(num, 10) do
-      rem when rem < 5 -> div
-      rem when rem >= 5 -> div + 1
-    end
-  end
-
-  defp rounding(_, _, _, div), do: div
-
-  Enum.reduce(0..104, 1, fn x, acc ->
+  Enum.reduce 0..15, 1, fn x, acc ->
    defp power_of_10(unquote(x)), do: unquote(acc)
    acc * 10
-  end)
-
-  Enum.reduce(0..104, 1, fn x, acc ->
-    defp power_of_5(unquote(x)), do: unquote(acc)
-    acc * 5
-  end)
+  end

  @doc """
-  Returns a pair of integers whose ratio is exactly equal
-  to the original float and with a positive denominator.
+  Returns a char list which corresponds to the text representation of the given float.
+
+  Inlined by the compiler.

  ## Examples

-      iex> Float.ratio(3.14)
-      {7070651414971679, 2251799813685248}
-      iex> Float.ratio(-3.14)
-      {-7070651414971679, 2251799813685248}
-      iex> Float.ratio(1.5)
-      {3, 2}
-      iex> Float.ratio(-1.5)
-      {-3, 2}
-      iex> Float.ratio(16.0)
-      {16, 1}
-      iex> Float.ratio(-16.0)
-      {-16, 1}
+      iex> Float.to_char_list(7.0)
+      '7.00000000000000000000e+00'

  """
-  @doc since: "1.4.0"
-  @spec ratio(float) :: {pos_integer | neg_integer, pos_integer}
-  def ratio(float) when is_float(float) do
-    <<sign::1, exp::11, significant::52-bitstring>> = <<float::float>>
-    {num, _, den} = decompose(significant)
-    num = sign(sign, num)
-
-    case exp - 1023 do
-      exp when exp > 0 ->
-        {den, exp} = shift_right(den, exp)
-        {shift_left(num, exp), den}
-
-      exp when exp < 0 ->
-        {num, shift_left(den, -exp)}
-
-      0 ->
-        {num, den}
-    end
+  @spec to_char_list(float) :: char_list
+  def to_char_list(float) do
+    :erlang.float_to_list(float)
  end

-  defp decompose(significant) do
-    decompose(significant, 1, 0, 2, 1, 1)
-  end
-
-  defp decompose(<<1::1, bits::bitstring>>, count, last_count, power, _last_power, acc) do
-    decompose(bits, count + 1, count, power <<< 1, power, shift_left(acc, count - last_count) + 1)
-  end
-
-  defp decompose(<<0::1, bits::bitstring>>, count, last_count, power, last_power, acc) do
-    decompose(bits, count + 1, last_count, power <<< 1, last_power, acc)
-  end
-
-  defp decompose(<<>>, _count, last_count, _power, last_power, acc) do
-    {acc, last_count, last_power}
-  end
-
-  defp sign(0, num), do: num
-  defp sign(1, num), do: -num
-
-  defp shift_left(num, 0), do: num
-  defp shift_left(num, times), do: shift_left(num <<< 1, times - 1)
-
-  defp shift_right(num, 0), do: {num, 0}
-  defp shift_right(1, times), do: {1, times}
-  defp shift_right(num, times), do: shift_right(num >>> 1, times - 1)
-
  @doc """
-  Returns a charlist which corresponds to the text representation
+  Returns a list which corresponds to the text representation
  of the given float.

-  It uses the shortest representation according to algorithm described
-  in "Printing Floating-Point Numbers Quickly and Accurately" in
-  Proceedings of the SIGPLAN '96 Conference on Programming Language
-  Design and Implementation.
+  ## Options
+
+    * `:decimals`   - number of decimal points to show
+    * `:scientific` - number of decimal points to show, in scientific format
+    * `:compact`    - when `true`, use the most compact representation (ignored
+      with the `scientific` option)

  ## Examples

-      iex> Float.to_charlist(7.0)
-      '7.0'
+      iex> Float.to_char_list 7.1, [decimals: 2, compact: true]
+      '7.1'

  """
-  @spec to_charlist(float) :: charlist
-  def to_charlist(float) when is_float(float) do
-    :io_lib_format.fwrite_g(float)
+  @spec to_char_list(float, list) :: char_list
+  def to_char_list(float, options) do
+    :erlang.float_to_list(float, expand_compact(options))
  end

  @doc """
  Returns a binary which corresponds to the text representation
  of the given float.

-  It uses the shortest representation according to algorithm described
-  in "Printing Floating-Point Numbers Quickly and Accurately" in
-  Proceedings of the SIGPLAN '96 Conference on Programming Language
-  Design and Implementation.
+  Inlined by the compiler.

  ## Examples

      iex> Float.to_string(7.0)
-      "7.0"
+      "7.00000000000000000000e+00"

  """
-  @spec to_string(float) :: String.t()
-  def to_string(float) when is_float(float) do
-    IO.iodata_to_binary(:io_lib_format.fwrite_g(float))
+  @spec to_string(float) :: String.t
+  def to_string(float) do
+    :erlang.float_to_binary(float)
  end

-  @doc false
-  # TODO: Remove by 2.0
-  @deprecated "Use Float.to_charlist/1 instead"
-  def to_char_list(float), do: Float.to_charlist(float)
+  @doc """
+  Returns a binary which corresponds to the text representation
+  of `float`.

-  @doc false
-  # TODO: Remove by 2.0
-  @deprecated "Use :erlang.float_to_list/2 instead"
-  def to_char_list(float, options) do
-    :erlang.float_to_list(float, expand_compact(options))
-  end
+  ## Options

-  @doc false
-  # TODO: Remove by 2.0
-  @deprecated "Use :erlang.float_to_binary/2 instead"
+    * `:decimals`   - number of decimal points to show
+    * `:scientific` - number of decimal points to show, in scientific format
+    * `:compact`    - when `true`, use the most compact representation (ignored
+      with the `scientific` option)
+
+  ## Examples
+
+      iex> Float.to_string 7.1, [decimals: 2, compact: true]
+      "7.1"
+
+  """
+  @spec to_string(float, list) :: String.t
  def to_string(float, options) do
    :erlang.float_to_binary(float, expand_compact(options))
  end

-  defp invalid_precision_message(precision) do
-    "precision #{precision} is out of valid range of #{inspect(@precision_range)}"
-  end
-
-  defp expand_compact([{:compact, false} | t]), do: expand_compact(t)
-  defp expand_compact([{:compact, true} | t]), do: [:compact | expand_compact(t)]
-  defp expand_compact([h | t]), do: [h | expand_compact(t)]
-  defp expand_compact([]), do: []
+  defp expand_compact([{:compact, false}|t]), do: expand_compact(t)
+  defp expand_compact([{:compact, true}|t]),  do: [:compact|expand_compact(t)]
+  defp expand_compact([h|t]),                 do: [h|expand_compact(t)]
+  defp expand_compact([]),                    do: []
 end
@@ -1,137 +0,0 @@
-defmodule Function do
-  @moduledoc """
-  A set of functions for working with functions.
-
-  There are two types of captured functions: **external** and **local**.
-  External functions are functions residing in modules that are captured
-  with `&/1`, such as `&String.length/1`. Local functions are anonymous functions
-  defined with `fn/1` or with the capture operator `&/1` using `&1`, `&2`,
-  and so on as replacements.
-  """
-
-  @type information ::
-          :arity
-          | :env
-          | :index
-          | :module
-          | :name
-          | :new_index
-          | :new_uniq
-          | :pid
-          | :type
-          | :uniq
-
-  @doc """
-  Captures the given function.
-
-  Inlined by the compiler.
-
-  ## Examples
-
-      iex> Function.capture(String, :length, 1)
-      &String.length/1
-
-  """
-  @doc since: "1.7.0"
-  @spec capture(module, atom, arity) :: fun
-  def capture(module, function_name, arity) do
-    :erlang.make_fun(module, function_name, arity)
-  end
-
-  @doc """
-  Returns a keyword list with information about a function.
-
-  The returned keys (with the corresponding possible values) for
-  all types of functions (local and external) are the following:
-
-    * `:type` - `:local` (for anonymous functions) or `:external` (for
-      named functions).
-
-    * `:module` - an atom which is the module where the function is defined when
-    anonymous or the module which the function refers to when it's a named function.
-
-    * `:arity` - (integer) the number of arguments the function is to be called with.
-
-    * `:name` - (atom) the name of the function.
-
-    * `:env` - a list of the environment or free variables. For named
-      functions, the returned list is always empty.
-
-  When `fun` is an anonymous function (that is, the type is `:local`), the following
-  additional keys are returned:
-
-    * `:pid` - PID of the process that originally created the function.
-
-    * `:index` - (integer) an index into the module function table.
-
-    * `:new_index` - (integer) an index into the module function table.
-
-    * `:new_uniq` - (binary) a unique value for this function. It's
-      calculated from the compiled code for the entire module.
-
-    * `:uniq` - (integer) a unique value for this function. This integer is
-      calculated from the compiled code for the entire module.
-
-  **Note**: this function must be used only for debugging purposes.
-
-  Inlined by the compiler.
-
-  ## Examples
-
-      iex> fun = fn x -> x end
-      iex> info = Function.info(fun)
-      iex> Keyword.get(info, :arity)
-      1
-      iex> Keyword.get(info, :type)
-      :local
-
-      iex> fun = &String.length/1
-      iex> info = Function.info(fun)
-      iex> Keyword.get(info, :type)
-      :external
-      iex> Keyword.get(info, :name)
-      :length
-
-  """
-  @doc since: "1.7.0"
-  @spec info(fun) :: [{information, term}]
-  def info(fun), do: :erlang.fun_info(fun)
-
-  @doc """
-  Returns a specific information about the function.
-
-  The returned information is a two-element tuple in the shape of
-  `{info, value}`.
-
-  For any function, the information asked for can be any of the atoms
-  `:module`, `:name`, `:arity`, `:env`, or `:type`.
-
-  For anonymous functions, there is also information about any of the
-  atoms `:index`, `:new_index`, `:new_uniq`, `:uniq`, and `:pid`.
-  For a named function, the value of any of these items is always the
-  atom `:undefined`.
-
-  For more information on each of the possible returned values, see
-  `info/1`.
-
-  Inlined by the compiler.
-
-  ## Examples
-
-      iex> f = fn x -> x end
-      iex> Function.info(f, :arity)
-      {:arity, 1}
-      iex> Function.info(f, :type)
-      {:type, :local}
-
-      iex> fun = &String.length/1
-      iex> Function.info(fun, :name)
-      {:name, :length}
-      iex> Function.info(fun, :pid)
-      {:pid, :undefined}
-
-  """
-  @doc since: "1.7.0"
-  @spec info(fun, item) :: {item, term} when item: information
-  def info(fun, item), do: :erlang.fun_info(fun, item)
-end
@@ -1,8 +1,19 @@
 defmodule GenEvent.Stream do
-  @moduledoc false
+  @moduledoc """
+  Defines a `GenEvent` stream.
+
+  This is a struct returned by `GenEvent.stream/2`. The struct is public and
+  contains the following fields:
+
+    * `:manager`  - the manager reference given to `GenEvent.stream/2`
+    * `:timeout`  - the timeout between events, defaults to `:infinity`
+
+  """
  defstruct manager: nil, timeout: :infinity

-  @type t :: %__MODULE__{manager: GenEvent.manager(), timeout: timeout}
+  @type t :: %__MODULE__{
+               manager: GenEvent.manager,
+               timeout: timeout}

  @doc false
  def init({_pid, _ref} = state) do
@@ -11,7 +22,7 @@ defmodule GenEvent.Stream do

  @doc false
  def handle_event(event, _state) do
-    # We do this to trick Dialyzer to not complain about non-local returns.
+    # We do this to trick dialyzer to not complain about non-local returns.
    case :erlang.phash2(1, 1) do
      0 -> exit({:bad_event, event})
      1 -> :remove_handler
@@ -20,9 +31,8 @@ defmodule GenEvent.Stream do

  @doc false
  def handle_call(msg, _state) do
-    # We do this to trick Dialyzer to not complain about non-local returns.
+    # We do this to trick dialyzer to not complain about non-local returns.
    reason = {:bad_call, msg}
-
    case :erlang.phash2(1, 1) do
      0 -> exit(reason)
      1 -> {:remove_handler, reason}
@@ -47,7 +57,7 @@ end

 defimpl Enumerable, for: GenEvent.Stream do
  def reduce(stream, acc, fun) do
-    start_fun = fn -> start(stream) end
+    start_fun = fn() -> start(stream) end
    next_fun = &next(stream, &1)
    stop_fun = &stop(stream, &1)
    Stream.resource(start_fun, next_fun, stop_fun).(acc, wrap_reducer(fun))
@@ -61,33 +71,26 @@ defimpl Enumerable, for: GenEvent.Stream do
    {:error, __MODULE__}
  end

-  def slice(_stream) do
-    {:error, __MODULE__}
-  end
-
  defp wrap_reducer(fun) do
    fn
      {:ack, manager, ref, event}, acc ->
-        send(manager, {ref, :ok})
+        send manager, {ref, :ok}
        fun.(event, acc)
-
      {:async, _manager, _ref, event}, acc ->
        fun.(event, acc)
-
      {:sync, manager, ref, event}, acc ->
        try do
          fun.(event, acc)
        after
-          send(manager, {ref, :ok})
+          send manager, {ref, :ok}
        end
    end
  end

  defp start(%{manager: manager} = stream) do
    try do
-      {:ok, {pid, ref}} =
-        :gen.call(manager, self(), {:add_process_handler, self(), self()}, :infinity)
-
+      {:ok, {pid, ref}} = :gen.call(manager, self(),
+                                    {:add_process_handler, self(), self()}, :infinity)
      mon_ref = Process.monitor(pid)
      {pid, ref, mon_ref}
    catch
@@ -135,7 +138,6 @@ defimpl Enumerable, for: GenEvent.Stream do
    case wait_for_handler_removal(pid, ref, mon_ref) do
      :ok ->
        flush_events(ref)
-
      {:error, reason} ->
        exit({reason, {__MODULE__, :stop, [stream, acc]}})
    end
@@ -144,7 +146,7 @@ defimpl Enumerable, for: GenEvent.Stream do
  # If we reach this branch, the handler was not removed yet,
  # so we trigger a request for doing so.
  defp stop(stream, {pid, ref, _} = acc) do
-    _ = :gen_event.delete_handler(pid, {pid, ref}, :shutdown)
+    _ = GenEvent.remove_handler(pid, {pid, ref}, :shutdown)
    stop(stream, {:removed, acc})
  end

@@ -153,7 +155,6 @@ defimpl Enumerable, for: GenEvent.Stream do
      {:gen_event_EXIT, {^pid, ^ref}, _reason} ->
        Process.demonitor(mon_ref, [:flush])
        :ok
-
      {:DOWN, ^mon_ref, _, _, reason} ->
        {:error, reason}
    end
@@ -161,8 +162,7 @@ defimpl Enumerable, for: GenEvent.Stream do

  defp flush_events(ref) do
    receive do
-      {_from, {_pid, ^ref}, {notify, _event}}
-      when notify in [:notify, :ack_notify, :sync_notify] ->
+      {_from, {_pid, ^ref}, {notify, _event}} when notify in [:notify, :ack_notify, :sync_notify] ->
        flush_events(ref)
    after
      0 -> :ok
@@ -1,14 +1,10 @@
 defmodule HashDict do
  @moduledoc """
-  Tuple-based HashDict implementation.
+  WARNING: this module is deprecated.

-  This module is deprecated. Use the `Map` module instead.
+  Use the `Map` module instead.
  """

-  @moduledoc deprecated: "Use Map instead"
-
-  # TODO: Remove by 2.0
-
  use Dict

  @node_bitmap 0b111
@@ -24,70 +20,58 @@ defmodule HashDict do
  @compile :inline_list_funcs
  @compile {:inline, key_hash: 1, key_mask: 1, key_shift: 1}

-  message = "Use maps and the Map module instead"
-
  @doc """
  Creates a new empty dict.
  """
-  @spec new :: Dict.t()
-  @deprecated message
+  @spec new :: Dict.t
  def new do
    %HashDict{}
  end

-  @deprecated message
  def put(%HashDict{root: root, size: size}, key, value) do
    {root, counter} = do_put(root, key, value, key_hash(key))
    %HashDict{root: root, size: size + counter}
  end

-  @deprecated message
  def update!(%HashDict{root: root, size: size} = dict, key, fun) when is_function(fun, 1) do
-    {root, counter} =
-      do_update(root, key, fn -> raise KeyError, key: key, term: dict end, fun, key_hash(key))
-
+    {root, counter} = do_update(root, key, fn -> raise KeyError, key: key, term: dict end,
+                                fun, key_hash(key))
    %HashDict{root: root, size: size + counter}
  end

-  @deprecated message
  def update(%HashDict{root: root, size: size}, key, initial, fun) when is_function(fun, 1) do
    {root, counter} = do_update(root, key, fn -> initial end, fun, key_hash(key))
    %HashDict{root: root, size: size + counter}
  end

-  @deprecated message
  def fetch(%HashDict{root: root}, key) do
    do_fetch(root, key, key_hash(key))
  end

-  @deprecated message
  def delete(dict, key) do
    case dict_delete(dict, key) do
      {dict, _value} -> dict
-      :error -> dict
+      :error         -> dict
    end
  end

-  @deprecated message
  def pop(dict, key, default \\ nil) do
    case dict_delete(dict, key) do
      {dict, value} -> {value, dict}
-      :error -> {default, dict}
+      :error        -> {default, dict}
    end
  end

-  @deprecated message
  def size(%HashDict{size: size}) do
    size
  end

  @doc false
-  @deprecated message
  def reduce(%HashDict{root: root}, acc, fun) do
    do_reduce(root, acc, fun, @node_size, fn
      {:suspend, acc} -> {:suspended, acc, &{:done, elem(&1, 1)}}
-      {:halt, acc} -> {:halted, acc}
-      {:cont, acc} -> {:done, acc}
+      {:halt, acc}    -> {:halted, acc}
+      {:cont, acc}    -> {:done, acc}
    end)
  end

@@ -97,7 +81,7 @@ defmodule HashDict do
  def dict_delete(%HashDict{root: root, size: size}, key) do
    case do_delete(root, key, key_hash(key)) do
      {root, value} -> {%HashDict{root: root, size: size - 1}, value}
-      :error -> :error
+      :error        -> :error
    end
  end

@@ -105,32 +89,26 @@ defmodule HashDict do

  defp do_fetch(node, key, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
-      [^key | v] -> {:ok, v}
+      [^key|v]     -> {:ok, v}
      {^key, v, _} -> {:ok, v}
-      {_, _, n} -> do_fetch(n, key, key_shift(hash))
-      _ -> :error
+      {_, _, n}    -> do_fetch(n, key, key_shift(hash))
+      _            -> :error
    end
  end

  defp do_put(node, key, value, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
      [] ->
-        {put_elem(node, index, [key | value]), 1}
-
-      [^key | _] ->
-        {put_elem(node, index, [key | value]), 0}
-
-      [k | v] ->
-        n = put_elem(@node_template, key_mask(key_shift(hash)), [key | value])
+        {put_elem(node, index, [key|value]), 1}
+      [^key|_] ->
+        {put_elem(node, index, [key|value]), 0}
+      [k|v] ->
+        n = put_elem(@node_template, key_mask(key_shift(hash)), [key|value])
        {put_elem(node, index, {k, v, n}), 1}
-
      {^key, _, n} ->
        {put_elem(node, index, {key, value, n}), 0}
-
      {k, v, n} ->
        {n, counter} = do_put(n, key, value, key_shift(hash))
        {put_elem(node, index, {k, v, n}), counter}
@@ -139,21 +117,16 @@ defmodule HashDict do

  defp do_update(node, key, initial, fun, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
      [] ->
-        {put_elem(node, index, [key | initial.()]), 1}
-
-      [^key | value] ->
-        {put_elem(node, index, [key | fun.(value)]), 0}
-
-      [k | v] ->
-        n = put_elem(@node_template, key_mask(key_shift(hash)), [key | initial.()])
+        {put_elem(node, index, [key|initial.()]), 1}
+      [^key|value] ->
+        {put_elem(node, index, [key|fun.(value)]), 0}
+      [k|v] ->
+        n = put_elem(@node_template, key_mask(key_shift(hash)), [key|initial.()])
        {put_elem(node, index, {k, v, n}), 1}
-
      {^key, value, n} ->
        {put_elem(node, index, {key, fun.(value), n}), 0}
-
      {k, v, n} ->
        {n, counter} = do_update(n, key, initial, fun, key_shift(hash))
        {put_elem(node, index, {k, v, n}), counter}
@@ -162,48 +135,40 @@ defmodule HashDict do

  defp do_delete(node, key, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
      [] ->
        :error
-
-      [^key | value] ->
+      [^key|value] ->
        {put_elem(node, index, []), value}
-
-      [_ | _] ->
+      [_|_] ->
        :error
-
      {^key, value, n} ->
        {put_elem(node, index, do_compact_node(n)), value}
-
      {k, v, n} ->
        case do_delete(n, key, key_shift(hash)) do
          {@node_template, value} ->
-            {put_elem(node, index, [k | v]), value}
-
+            {put_elem(node, index, [k|v]), value}
          {n, value} ->
            {put_elem(node, index, {k, v, n}), value}
-
          :error ->
            :error
        end
    end
  end

-  Enum.each(0..(@node_size - 1), fn index ->
+  Enum.each 0..(@node_size - 1), fn index ->
    defp do_compact_node(node) when elem(node, unquote(index)) != [] do
      case elem(node, unquote(index)) do
-        [k | v] ->
+        [k|v] ->
          case put_elem(node, unquote(index), []) do
-            @node_template -> [k | v]
+            @node_template -> [k|v]
            n -> {k, v, n}
          end
-
        {k, v, n} ->
          {k, v, put_elem(node, unquote(index), do_compact_node(n))}
      end
    end
-  end)
+  end

  ## Dict reduce

@@ -219,7 +184,7 @@ defmodule HashDict do
    next.(acc)
  end

-  defp do_reduce_each([k | v], {:cont, acc}, fun, next) do
+  defp do_reduce_each([k|v], {:cont, acc}, fun, next) do
    next.(fun.({k, v}, acc))
  end

@@ -228,12 +193,7 @@ defmodule HashDict do
  end

  defp do_reduce(node, acc, fun, count, next) when count > 0 do
-    do_reduce_each(
-      :erlang.element(count, node),
-      acc,
-      fun,
-      &do_reduce(node, &1, fun, count - 1, next)
-    )
+    do_reduce_each(:erlang.element(count, node), acc, fun, &do_reduce(node, &1, fun, count - 1, next))
  end

  defp do_reduce(_node, acc, _fun, 0, next) do
@@ -258,45 +218,19 @@ defmodule HashDict do
 end

 defimpl Enumerable, for: HashDict do
-  def reduce(dict, acc, fun) do
-    # Avoid warnings about HashDict being deprecated.
-    module = HashDict
-    module.reduce(dict, acc, fun)
-  end
-
-  def member?(dict, {key, value}) do
-    # Avoid warnings about HashDict being deprecated.
-    module = HashDict
-    {:ok, match?({:ok, ^value}, module.fetch(dict, key))}
-  end
-
-  def member?(_dict, _) do
-    {:ok, false}
-  end
-
-  def count(dict) do
-    # Avoid warnings about HashDict being deprecated.
-    module = HashDict
-    {:ok, module.size(dict)}
-  end
-
-  def slice(_dict) do
-    {:error, __MODULE__}
-  end
+  def reduce(dict, acc, fun),  do: HashDict.reduce(dict, acc, fun)
+  def member?(dict, {k, v}), do: {:ok, match?({:ok, ^v}, HashDict.fetch(dict, k))}
+  def member?(_dict, _),       do: {:ok, false}
+  def count(dict),             do: {:ok, HashDict.size(dict)}
 end

 defimpl Collectable, for: HashDict do
  def into(original) do
-    # Avoid warnings about HashDict being deprecated.
-    module = HashDict
-
-    collector_fun = fn
-      dict, {:cont, {key, value}} -> module.put(dict, key, value)
+    {original, fn
+      dict, {:cont, {k, v}} -> HashDict.put(dict, k, v)
      dict, :done -> dict
      _, :halt -> :ok
-    end
-
-    {original, collector_fun}
+    end}
  end
 end

@@ -304,8 +238,6 @@ defimpl Inspect, for: HashDict do
  import Inspect.Algebra

  def inspect(dict, opts) do
-    # Avoid warnings about HashDict being deprecated.
-    module = HashDict
-    concat(["#HashDict<", Inspect.List.inspect(module.to_list(dict), opts), ">"])
+    concat ["#HashDict<", Inspect.List.inspect(HashDict.to_list(dict), opts), ">"]
  end
 end
@@ -1,19 +1,17 @@
 defmodule HashSet do
  @moduledoc """
-  Tuple-based HashSet implementation.
+  WARNING: this module is deprecated.

-  This module is deprecated. Use the `MapSet` module instead.
+  Use the `MapSet` module instead.
  """

-  @moduledoc deprecated: "Use MapSet instead"
+  @behaviour Set

  @node_bitmap 0b111
  @node_shift 3
  @node_size 8
  @node_template :erlang.make_tuple(@node_size, [])

-  message = "Use the MapSet module instead"
-
  @opaque t :: %__MODULE__{size: non_neg_integer, root: term}
  @doc false
  defstruct size: 0, root: @node_template
@@ -22,85 +20,71 @@ defmodule HashSet do
  @compile :inline_list_funcs
  @compile {:inline, key_hash: 1, key_mask: 1, key_shift: 1}

-  @deprecated message
-  @spec new :: Set.t()
+  @spec new :: Set.t
  def new do
    %HashSet{}
  end

-  @deprecated message
  def union(%HashSet{size: size1} = set1, %HashSet{size: size2} = set2) when size1 <= size2 do
-    set_fold(set1, set2, fn v, acc -> put(acc, v) end)
+    set_fold set1, set2, fn v, acc -> put(acc, v) end
  end

-  @deprecated message
  def union(%HashSet{} = set1, %HashSet{} = set2) do
-    set_fold(set2, set1, fn v, acc -> put(acc, v) end)
+    set_fold set2, set1, fn v, acc -> put(acc, v) end
  end

-  @deprecated message
  def intersection(%HashSet{} = set1, %HashSet{} = set2) do
-    set_fold(set1, %HashSet{}, fn v, acc ->
+    set_fold set1, %HashSet{}, fn v, acc ->
      if member?(set2, v), do: put(acc, v), else: acc
-    end)
-  end
-
-  @deprecated message
-  def difference(%HashSet{} = set1, %HashSet{} = set2) do
-    set_fold(set2, set1, fn v, acc -> delete(acc, v) end)
-  end
-
-  @deprecated message
-  def to_list(set) do
-    set_fold(set, [], &[&1 | &2]) |> :lists.reverse()
-  end
-
-  @deprecated message
-  def equal?(%HashSet{size: size1} = set1, %HashSet{size: size2} = set2) do
-    case size1 do
-      ^size2 -> subset?(set1, set2)
-      _ -> false
    end
  end

-  @deprecated message
+  def difference(%HashSet{} = set1, %HashSet{} = set2) do
+    set_fold set2, set1, fn v, acc -> delete(acc, v) end
+  end
+
+  def to_list(set) do
+    set_fold(set, [], &[&1|&2]) |> :lists.reverse
+  end
+
+  def equal?(%HashSet{size: size1} = set1, %HashSet{size: size2} = set2) do
+    case size1 do
+      ^size2 -> subset?(set1, set2)
+      _      -> false
+    end
+  end
+
  def subset?(%HashSet{} = set1, %HashSet{} = set2) do
    reduce(set1, {:cont, true}, fn member, acc ->
      case member?(set2, member) do
        true -> {:cont, acc}
-        _ -> {:halt, false}
+        _    -> {:halt, false}
      end
-    end)
-    |> elem(1)
+    end) |> elem(1)
  end

-  @deprecated message
  def disjoint?(%HashSet{} = set1, %HashSet{} = set2) do
    reduce(set2, {:cont, true}, fn member, acc ->
      case member?(set1, member) do
        false -> {:cont, acc}
-        _ -> {:halt, false}
+        _     -> {:halt, false}
      end
-    end)
-    |> elem(1)
+    end) |> elem(1)
  end

-  @deprecated message
  def member?(%HashSet{root: root}, term) do
    do_member?(root, term, key_hash(term))
  end

-  @deprecated message
  def put(%HashSet{root: root, size: size}, term) do
    {root, counter} = do_put(root, term, key_hash(term))
    %HashSet{root: root, size: size + counter}
  end

-  @deprecated message
  def delete(%HashSet{root: root, size: size} = set, term) do
    case do_delete(root, term, key_hash(term)) do
      {:ok, root} -> %HashSet{root: root, size: size - 1}
-      :error -> set
+      :error      -> set
    end
  end

@@ -108,12 +92,11 @@ defmodule HashSet do
  def reduce(%HashSet{root: root}, acc, fun) do
    do_reduce(root, acc, fun, @node_size, fn
      {:suspend, acc} -> {:suspended, acc, &{:done, elem(&1, 1)}}
-      {:halt, acc} -> {:halted, acc}
-      {:cont, acc} -> {:done, acc}
+      {:halt, acc}    -> {:halted, acc}
+      {:cont, acc}    -> {:done, acc}
    end)
  end

-  @deprecated message
  def size(%HashSet{size: size}) do
    size
  end
@@ -128,85 +111,72 @@ defmodule HashSet do

  defp do_member?(node, term, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
-      [] -> false
-      [^term | _] -> true
-      [_] -> false
-      [_ | n] -> do_member?(n, term, key_shift(hash))
+      []        -> false
+      [^term|_] -> true
+      [_]       -> false
+      [_|n]     -> do_member?(n, term, key_shift(hash))
    end
  end

  defp do_put(node, term, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
      [] ->
        {put_elem(node, index, [term]), 1}
-
-      [^term | _] ->
+      [^term|_] ->
        {node, 0}
-
      [t] ->
        n = put_elem(@node_template, key_mask(key_shift(hash)), [term])
-        {put_elem(node, index, [t | n]), 1}
-
-      [t | n] ->
+        {put_elem(node, index, [t|n]), 1}
+      [t|n] ->
        {n, counter} = do_put(n, term, key_shift(hash))
-        {put_elem(node, index, [t | n]), counter}
+        {put_elem(node, index, [t|n]), counter}
    end
  end

  defp do_delete(node, term, hash) do
    index = key_mask(hash)
-
    case elem(node, index) do
      [] ->
        :error
-
      [^term] ->
        {:ok, put_elem(node, index, [])}
-
      [_] ->
        :error
-
-      [^term | n] ->
+      [^term|n] ->
        {:ok, put_elem(node, index, do_compact_node(n))}
-
-      [t | n] ->
+      [t|n] ->
        case do_delete(n, term, key_shift(hash)) do
          {:ok, @node_template} ->
            {:ok, put_elem(node, index, [t])}
-
          {:ok, n} ->
-            {:ok, put_elem(node, index, [t | n])}
-
+            {:ok, put_elem(node, index, [t|n])}
          :error ->
            :error
        end
    end
  end

-  Enum.each(0..(@node_size - 1), fn index ->
+  Enum.each 0..(@node_size - 1), fn index ->
    defp do_compact_node(node) when elem(node, unquote(index)) != [] do
      case elem(node, unquote(index)) do
        [t] ->
          case put_elem(node, unquote(index), []) do
            @node_template -> [t]
-            n -> [t | n]
+            n -> [t|n]
          end
-
-        [t | n] ->
-          [t | put_elem(node, unquote(index), do_compact_node(n))]
+        [t|n] ->
+          [t|put_elem(node, unquote(index), do_compact_node(n))]
      end
    end
-  end)
+  end

  ## Set fold

-  defp do_fold_each([], acc, _fun), do: acc
-  defp do_fold_each([t], acc, fun), do: fun.(t, acc)
-  defp do_fold_each([t | n], acc, fun), do: do_fold(n, fun.(t, acc), fun, @node_size)
+  defp do_fold_each([], acc, _fun),   do: acc
+  defp do_fold_each([t], acc, fun),   do: fun.(t, acc)
+  defp do_fold_each([t|n], acc, fun), do: do_fold(n, fun.(t, acc), fun, @node_size)

  defp do_fold(node, acc, fun, count) when count > 0 do
    acc = do_fold_each(:erlang.element(count, node), acc, fun)
@@ -235,17 +205,12 @@ defmodule HashSet do
    next.(fun.(t, acc))
  end

-  defp do_reduce_each([t | n], {:cont, acc}, fun, next) do
+  defp do_reduce_each([t|n], {:cont, acc}, fun, next) do
    do_reduce(n, fun.(t, acc), fun, @node_size, next)
  end

  defp do_reduce(node, acc, fun, count, next) when count > 0 do
-    do_reduce_each(
-      :erlang.element(count, node),
-      acc,
-      fun,
-      &do_reduce(node, &1, fun, count - 1, next)
-    )
+    do_reduce_each(:erlang.element(count, node), acc, fun, &do_reduce(node, &1, fun, count - 1, next))
  end

  defp do_reduce(_node, acc, _fun, 0, next) do
@@ -270,41 +235,18 @@ defmodule HashSet do
 end

 defimpl Enumerable, for: HashSet do
-  def reduce(set, acc, fun) do
-    # Avoid warnings about HashSet being deprecated.
-    module = HashSet
-    module.reduce(set, acc, fun)
-  end
-
-  def member?(set, term) do
-    # Avoid warnings about HashSet being deprecated.
-    module = HashSet
-    {:ok, module.member?(set, term)}
-  end
-
-  def count(set) do
-    # Avoid warnings about HashSet being deprecated.
-    module = HashSet
-    {:ok, module.size(set)}
-  end
-
-  def slice(_set) do
-    {:error, __MODULE__}
-  end
+  def reduce(set, acc, fun), do: HashSet.reduce(set, acc, fun)
+  def member?(set, v),       do: {:ok, HashSet.member?(set, v)}
+  def count(set),            do: {:ok, HashSet.size(set)}
 end

 defimpl Collectable, for: HashSet do
  def into(original) do
-    # Avoid warnings about HashSet being deprecated.
-    module = HashSet
-
-    collector_fun = fn
-      set, {:cont, term} -> module.put(set, term)
+    {original, fn
+      set, {:cont, x} -> HashSet.put(set, x)
      set, :done -> set
      _, :halt -> :ok
-    end
-
-    {original, collector_fun}
+    end}
  end
 end

@@ -312,8 +254,6 @@ defimpl Inspect, for: HashSet do
  import Inspect.Algebra

  def inspect(set, opts) do
-    # Avoid warnings about HashSet being deprecated.
-    module = HashSet
-    concat(["#HashSet<", Inspect.List.inspect(module.to_list(set), opts), ">"])
+    concat ["#HashSet<", Inspect.List.inspect(HashSet.to_list(set), opts), ">"]
  end
 end
@@ -1,21 +1,17 @@
 import Kernel, except: [inspect: 1]
 import Inspect.Algebra

-alias Code.Identifier
-
 defprotocol Inspect do
  @moduledoc """
-  The `Inspect` protocol converts an Elixir data structure into an
-  algebra document.
-
-  This documentation refers to implementing the `Inspect` protocol
-  for your own data structures. To learn more about using inspect,
-  see `Kernel.inspect/2` and `IO.inspect/2`.
+  The `Inspect` protocol is responsible for converting any Elixir
+  data structure into an algebra document. This document is then
+  formatted, either in pretty printing format or a regular one.

  The `inspect/2` function receives the entity to be inspected
  followed by the inspecting options, represented by the struct
-  `Inspect.Opts`. Building of the algebra document is done with
-  `Inspect.Algebra`.
+  `Inspect.Opts`.
+
+  Inspection is done using the functions available in `Inspect.Algebra`.

  ## Examples

@@ -27,11 +23,11 @@ defprotocol Inspect do
        import Inspect.Algebra

        def inspect(dict, opts) do
-          concat(["#MapSet<", to_doc(MapSet.to_list(dict), opts), ">"])
+          concat ["#MapSet<", to_doc(MapSet.to_list(dict), opts), ">"]
        end
      end

-  The `concat/1` function comes from `Inspect.Algebra` and it
+  The `concat` function comes from `Inspect.Algebra` and it
  concatenates algebra documents together. In the example above,
  it is concatenating the string `"MapSet<"` (all strings are
  valid algebra documents that keep their formatting when pretty
@@ -52,285 +48,428 @@ defprotocol Inspect do
  implementation directly. For example, to test Inspect.MapSet above,
  you can invoke it as:

-      Inspect.MapSet.inspect(MapSet.new(), %Inspect.Opts{})
+      Inspect.MapSet.inspect(MapSet.new, %Inspect.Opts{})

  """

  # Handle structs in Any
  @fallback_to_any true

-  def inspect(term, opts)
+  def inspect(thing, opts)
 end

 defimpl Inspect, for: Atom do
  require Macro

-  def inspect(atom, opts) do
-    color(Identifier.inspect_as_atom(atom), color_key(atom), opts)
+  def inspect(atom, _opts) do
+    inspect(atom)
  end

-  defp color_key(atom) when is_boolean(atom), do: :boolean
-  defp color_key(nil), do: nil
-  defp color_key(_), do: :atom
-end
+  def inspect(false),  do: "false"
+  def inspect(true),   do: "true"
+  def inspect(nil),    do: "nil"
+  def inspect(:""),    do: ":\"\""

-defimpl Inspect, for: BitString do
-  def inspect(term, opts) when is_binary(term) do
-    %Inspect.Opts{binaries: bins, base: base, printable_limit: printable_limit} = opts
+  def inspect(atom) do
+    binary = Atom.to_string(atom)

-    if base == :decimal and
-         (bins == :as_strings or (bins == :infer and String.printable?(term, printable_limit))) do
-      inspected =
-        case Identifier.escape(term, ?", printable_limit) do
-          {escaped, ""} -> [?", escaped, ?"]
-          {escaped, _} -> [?", escaped, ?", " <> ..."]
+    cond do
+      valid_ref_identifier?(binary) ->
+        if only_elixir?(binary) do
+          binary
+        else
+          "Elixir." <> rest = binary
+          rest
        end
-
-      color(IO.iodata_to_binary(inspected), :string, opts)
-    else
-      inspect_bitstring(term, opts)
+      valid_atom_identifier?(binary) ->
+        ":" <> binary
+      atom in [:%{}, :{}, :<<>>, :..., :%] ->
+        ":" <> binary
+      atom in Macro.binary_ops or atom in Macro.unary_ops ->
+        ":" <> binary
+      true ->
+        <<?:, ?", Inspect.BitString.escape(binary, ?")::binary, ?">>
    end
  end

-  def inspect(term, opts) do
-    inspect_bitstring(term, opts)
+  defp only_elixir?("Elixir." <> rest), do: only_elixir?(rest)
+  defp only_elixir?("Elixir"), do: true
+  defp only_elixir?(_), do: false
+
+  # Detect if atom is an atom alias (Elixir.Foo.Bar.Baz)
+
+  defp valid_ref_identifier?("Elixir" <> rest) do
+    valid_ref_piece?(rest)
  end

-  defp inspect_bitstring("", opts) do
-    color("<<>>", :binary, opts)
+  defp valid_ref_identifier?(_), do: false
+
+  defp valid_ref_piece?(<<?., h, t::binary>>) when h in ?A..?Z do
+    valid_ref_piece? valid_identifier?(t)
  end

+  defp valid_ref_piece?(<<>>), do: true
+  defp valid_ref_piece?(_),    do: false
+
+  # Detect if atom
+
+  defp valid_atom_identifier?(<<h, t::binary>>) when h in ?a..?z or h in ?A..?Z or h == ?_ do
+    valid_atom_piece?(t)
+  end
+
+  defp valid_atom_identifier?(_), do: false
+
+  defp valid_atom_piece?(t) do
+    case valid_identifier?(t) do
+      <<>>              -> true
+      <<??>>            -> true
+      <<?!>>            -> true
+      <<?@, t::binary>> -> valid_atom_piece?(t)
+      _                 -> false
+    end
+  end
+
+  defp valid_identifier?(<<h, t::binary>>)
+      when h in ?a..?z
+      when h in ?A..?Z
+      when h in ?0..?9
+      when h == ?_ do
+    valid_identifier? t
+  end
+
+  defp valid_identifier?(other), do: other
+end
+
+defimpl Inspect, for: BitString do
+  def inspect(thing, %Inspect.Opts{binaries: bins} = opts) when is_binary(thing) do
+    if bins == :as_strings or (bins == :infer and String.printable?(thing)) do
+      <<?", escape(thing, ?")::binary, ?">>
+    else
+      inspect_bitstring(thing, opts)
+    end
+  end
+
+  def inspect(thing, opts) do
+    inspect_bitstring(thing, opts)
+  end
+
+  ## Escaping
+
+  @doc false
+  def escape(other, char) do
+    escape(other, char, <<>>)
+  end
+
+  defp escape(<<char, t::binary >>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, char>>)
+  end
+  defp escape(<<?#, ?{, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?#, ?{>>)
+  end
+  defp escape(<<?\a, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?a>>)
+  end
+  defp escape(<<?\b, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?b>>)
+  end
+  defp escape(<<?\d, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?d>>)
+  end
+  defp escape(<<?\e, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?e>>)
+  end
+  defp escape(<<?\f, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?f>>)
+  end
+  defp escape(<<?\n, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?n>>)
+  end
+  defp escape(<<?\r, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?r>>)
+  end
+  defp escape(<<?\\, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?\\>>)
+  end
+  defp escape(<<?\t, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?t>>)
+  end
+  defp escape(<<?\v, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, ?\\, ?v>>)
+  end
+  defp escape(<<h::utf8, t::binary>>, char, binary) do
+    head = <<h::utf8 >>
+    if String.printable?(head) do
+      escape(t, char, append(head, binary))
+    else
+      <<byte::8, h::binary >> = head
+      t = <<h::binary, t::binary>>
+      escape(t, char, <<binary::binary, escape_char(byte)::binary>>)
+    end
+  end
+  defp escape(<<h, t::binary>>, char, binary) do
+    escape(t, char, <<binary::binary, escape_char(h)::binary>>)
+  end
+  defp escape(<<>>, _char, binary), do: binary
+
+  @doc false
+  # Also used by Regex
+  def escape_char(0) do
+    <<?\\, ?0>>
+  end
+
+  def escape_char(char) when char < 0x100 do
+    <<a::4, b::4>> = <<char::8>>
+    <<?\\, ?x, to_hex(a), to_hex(b)>>
+  end
+
+  def escape_char(char) when char < 0x10000 do
+    <<a::4, b::4, c::4, d::4>> = <<char::16>>
+    <<?\\, ?x, ?{, to_hex(a), to_hex(b), to_hex(c), to_hex(d), ?}>>
+  end
+
+  def escape_char(char) when char < 0x1000000 do
+    <<a::4, b::4, c::4, d::4, e::4, f::4>> = <<char::24>>
+    <<?\\, ?x, ?{, to_hex(a), to_hex(b), to_hex(c),
+                   to_hex(d), to_hex(e), to_hex(f), ?}>>
+  end
+
+  defp to_hex(c) when c in 0..9, do: ?0+c
+  defp to_hex(c) when c in 10..15, do: ?A+c-10
+
+  defp append(<<h, t::binary>>, binary), do: append(t, <<binary::binary, h>>)
+  defp append(<<>>, binary), do: binary
+
+  ## Bitstrings
+
  defp inspect_bitstring(bitstring, opts) do
-    left = color("<<", :binary, opts)
-    right = color(">>", :binary, opts)
-    inner = each_bit(bitstring, opts.limit, opts)
-    group(concat(concat(left, nest(inner, 2)), right))
+    each_bit(bitstring, opts.limit, "<<") <> ">>"
  end

-  defp each_bit(_, 0, _) do
-    "..."
+  defp each_bit(_, 0, acc) do
+    acc <> "..."
  end

-  defp each_bit(<<>>, _counter, _opts) do
-    :doc_nil
+  defp each_bit(<<h, t::bitstring>>, counter, acc) when t != <<>> do
+    each_bit(t, decrement(counter), acc <> Integer.to_string(h) <> ", ")
  end

-  defp each_bit(<<h::8>>, _counter, opts) do
-    Inspect.Integer.inspect(h, opts)
+  defp each_bit(<<h::8>>, _counter, acc) do
+    acc <> Integer.to_string(h)
  end

-  defp each_bit(<<h, t::bitstring>>, counter, opts) do
-    flex_glue(
-      concat(Inspect.Integer.inspect(h, opts), ","),
-      each_bit(t, decrement(counter), opts)
-    )
+  defp each_bit(<<>>, _counter, acc) do
+    acc
  end

-  defp each_bit(bitstring, _counter, opts) do
+  defp each_bit(bitstring, _counter, acc) do
    size = bit_size(bitstring)
    <<h::size(size)>> = bitstring
-    Inspect.Integer.inspect(h, opts) <> "::size(" <> Integer.to_string(size) <> ")"
+    acc <> Integer.to_string(h) <> "::size(" <> Integer.to_string(size) <> ")"
  end

-  @compile {:inline, decrement: 1}
  defp decrement(:infinity), do: :infinity
-  defp decrement(counter), do: counter - 1
+  defp decrement(counter),   do: counter - 1
 end

 defimpl Inspect, for: List do
-  def inspect([], opts) do
-    color("[]", :list, opts)
-  end
-
-  # TODO: Remove :char_list and :as_char_lists handling in 2.0
-  def inspect(term, opts) do
-    %Inspect.Opts{
-      charlists: lists,
-      char_lists: lists_deprecated,
-      printable_limit: printable_limit
-    } = opts
-
-    lists =
-      if lists == :infer and lists_deprecated != :infer do
-        case lists_deprecated do
-          :as_char_lists ->
-            IO.warn(
-              "the :char_lists inspect option and its :as_char_lists " <>
-                "value are deprecated, use the :charlists option and its " <>
-                ":as_charlists value instead"
-            )
-
-            :as_charlists
-
-          _ ->
-            IO.warn("the :char_lists inspect option is deprecated, use :charlists instead")
-            lists_deprecated
-        end
-      else
-        lists
-      end
-
-    open = color("[", :list, opts)
-    sep = color(",", :list, opts)
-    close = color("]", :list, opts)
+  def inspect([], _opts), do: "[]"

+  def inspect(thing, %Inspect.Opts{char_lists: lists} = opts) do
    cond do
-      lists == :as_charlists or (lists == :infer and List.ascii_printable?(term, printable_limit)) ->
-        inspected =
-          case Identifier.escape(IO.chardata_to_string(term), ?', printable_limit) do
-            {escaped, ""} -> [?', escaped, ?']
-            {escaped, _} -> [?', escaped, ?', " ++ ..."]
-          end
-
-        IO.iodata_to_binary(inspected)
-
-      keyword?(term) ->
-        container_doc(open, term, close, opts, &keyword/2, separator: sep, break: :strict)
-
+      lists == :as_char_lists or (lists == :infer and printable?(thing)) ->
+        <<?', Inspect.BitString.escape(IO.chardata_to_string(thing), ?')::binary, ?'>>
+      keyword?(thing) ->
+        surround_many("[", thing, "]", opts, &keyword/2)
      true ->
-        container_doc(open, term, close, opts, &to_doc/2, separator: sep)
+        surround_many("[", thing, "]", opts, &to_doc/2)
    end
  end

  @doc false
  def keyword({key, value}, opts) do
-    key = color(Identifier.inspect_as_key(key), :atom, opts)
-    concat(key, concat(" ", to_doc(value, opts)))
+    concat(
+      key_to_binary(key) <> ": ",
+      to_doc(value, opts)
+    )
  end

  @doc false
  def keyword?([{key, _value} | rest]) when is_atom(key) do
-    case Atom.to_charlist(key) do
+    case Atom.to_char_list(key) do
      'Elixir.' ++ _ -> false
      _ -> keyword?(rest)
    end
  end

-  def keyword?([]), do: true
+  def keyword?([]),     do: true
  def keyword?(_other), do: false
+
+  @doc false
+  def printable?([c|cs]) when is_integer(c) and c in 32..126, do: printable?(cs)
+  def printable?([?\n|cs]), do: printable?(cs)
+  def printable?([?\r|cs]), do: printable?(cs)
+  def printable?([?\t|cs]), do: printable?(cs)
+  def printable?([?\v|cs]), do: printable?(cs)
+  def printable?([?\b|cs]), do: printable?(cs)
+  def printable?([?\f|cs]), do: printable?(cs)
+  def printable?([?\e|cs]), do: printable?(cs)
+  def printable?([?\a|cs]), do: printable?(cs)
+  def printable?([]), do: true
+  def printable?(_), do: false
+
+  ## Private
+
+  defp key_to_binary(key) do
+    case Inspect.Atom.inspect(key) do
+      ":" <> right -> right
+      other -> other
+    end
+  end
 end

 defimpl Inspect, for: Tuple do
+  def inspect({}, _opts), do: "{}"
+
  def inspect(tuple, opts) do
-    open = color("{", :tuple, opts)
-    sep = color(",", :tuple, opts)
-    close = color("}", :tuple, opts)
-    container_opts = [separator: sep, break: :flex]
-    container_doc(open, Tuple.to_list(tuple), close, opts, &to_doc/2, container_opts)
+    surround_many("{", Tuple.to_list(tuple), "}", opts, &to_doc/2)
  end
 end

 defimpl Inspect, for: Map do
  def inspect(map, opts) do
-    inspect(map, "", opts)
+    nest inspect(map, "", opts), 1
  end

  def inspect(map, name, opts) do
    map = :maps.to_list(map)
-    open = color("%" <> name <> "{", :map, opts)
-    sep = color(",", :map, opts)
-    close = color("}", :map, opts)
-    container_doc(open, map, close, opts, traverse_fun(map, opts), separator: sep, break: :strict)
+    surround_many("%" <> name <> "{", map, "}", opts, traverse_fun(map))
  end

-  defp traverse_fun(list, opts) do
+  defp traverse_fun(list) do
    if Inspect.List.keyword?(list) do
      &Inspect.List.keyword/2
    else
-      sep = color(" => ", :map, opts)
-      &to_map(&1, &2, sep)
+      &to_map/2
    end
  end

-  defp to_map({key, value}, opts, sep) do
-    concat(concat(to_doc(key, opts), sep), to_doc(value, opts))
+  defp to_map({key, value}, opts) do
+    concat(
+      concat(to_doc(key, opts), " => "),
+      to_doc(value, opts)
+    )
  end
 end

 defimpl Inspect, for: Integer do
-  def inspect(term, %Inspect.Opts{base: base} = opts) do
-    inspected = Integer.to_string(term, base_to_value(base)) |> prepend_prefix(base)
-    color(inspected, :number, opts)
+  def inspect(thing, %Inspect.Opts{base: base}) do
+    Integer.to_string(thing, base_to_value(base))
+    |> prepend_prefix(base)
  end

  defp base_to_value(base) do
    case base do
-      :binary -> 2
+      :binary  -> 2
      :decimal -> 10
-      :octal -> 8
-      :hex -> 16
+      :octal   -> 8
+      :hex     -> 16
    end
  end

  defp prepend_prefix(value, :decimal), do: value
-
-  defp prepend_prefix(<<?-, value::binary>>, base) do
-    "-" <> prepend_prefix(value, base)
-  end
-
  defp prepend_prefix(value, base) do
-    prefix =
-      case base do
-        :binary -> "0b"
-        :octal -> "0o"
-        :hex -> "0x"
-      end
-
+    prefix = case base do
+      :binary -> "0b"
+      :octal  -> "0o"
+      :hex    -> "0x"
+    end
    prefix <> value
  end
 end

 defimpl Inspect, for: Float do
-  def inspect(term, opts) do
-    inspected = IO.iodata_to_binary(:io_lib_format.fwrite_g(term))
-    color(inspected, :number, opts)
+  def inspect(thing, _opts) do
+    IO.iodata_to_binary(:io_lib_format.fwrite_g(thing))
  end
 end

 defimpl Inspect, for: Regex do
-  def inspect(regex, opts) do
-    {escaped, _} = Identifier.escape(regex.source, ?/, :infinity, &escape_map/1)
-    source = IO.iodata_to_binary(['~r/', escaped, ?/, regex.opts])
-    color(source, :regex, opts)
+  def inspect(regex, _opts) do
+    delim = ?/
+    concat ["~r",
+            <<delim, escape(regex.source, delim)::binary, delim>>,
+            regex.opts]
  end

-  defp escape_map(?\a), do: '\\a'
-  defp escape_map(?\f), do: '\\f'
-  defp escape_map(?\n), do: '\\n'
-  defp escape_map(?\r), do: '\\r'
-  defp escape_map(?\t), do: '\\t'
-  defp escape_map(?\v), do: '\\v'
-  defp escape_map(_), do: false
+  defp escape(bin, term),
+    do: escape(bin, <<>>, term)
+
+  defp escape(<<?\\, term>> <> rest, buf, term),
+    do: escape(rest, buf <> <<?\\, term>>, term)
+
+  defp escape(<<term>> <> rest, buf, term),
+    do: escape(rest, buf <> <<?\\, term>>, term)
+
+  # the list of characters is from "String.printable?" impl
+  # minus characters treated specially by regex: \s, \d, \b, \e
+
+  defp escape(<<?\n>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?n>>, term)
+
+  defp escape(<<?\r>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?r>>, term)
+
+  defp escape(<<?\t>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?t>>, term)
+
+  defp escape(<<?\v>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?v>>, term)
+
+  defp escape(<<?\f>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?f>>, term)
+
+  defp escape(<<?\a>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, ?\\, ?a>>, term)
+
+  defp escape(<<c::utf8>> <> rest, buf, term) do
+    charstr = <<c::utf8>>
+    if String.printable?(charstr) and not c in [?\d, ?\b, ?\e] do
+      escape(rest, buf <> charstr, term)
+    else
+      escape(rest, buf <> Inspect.BitString.escape_char(c), term)
+    end
+  end
+
+  defp escape(<<c>> <> rest, buf, term),
+    do: escape(rest, <<buf::binary, Inspect.BitString.escape_char(c)>>, term)
+
+  defp escape(<<>>, buf, _), do: buf
 end

 defimpl Inspect, for: Function do
  def inspect(function, _opts) do
-    fun_info = Function.info(function)
+    fun_info = :erlang.fun_info(function)
    mod = fun_info[:module]
-    name = fun_info[:name]

-    cond do
-      fun_info[:type] == :external and fun_info[:env] == [] ->
-        inspected_as_atom = Identifier.inspect_as_atom(mod)
-        inspected_as_function = Identifier.inspect_as_function(name)
-        "&#{inspected_as_atom}.#{inspected_as_function}/#{fun_info[:arity]}"
-
-      match?('elixir_compiler_' ++ _, Atom.to_charlist(mod)) ->
-        if function_exported?(mod, :__RELATIVE__, 0) do
-          "#Function<#{uniq(fun_info)} in file:#{mod.__RELATIVE__}>"
-        else
+    if fun_info[:type] == :external and fun_info[:env] == [] do
+      "&#{Inspect.Atom.inspect(mod)}.#{fun_info[:name]}/#{fun_info[:arity]}"
+    else
+      case Atom.to_char_list(mod) do
+        'elixir_compiler_' ++ _ ->
+          if function_exported?(mod, :__RELATIVE__, 0) do
+            "#Function<#{uniq(fun_info)} in file:#{mod.__RELATIVE__}>"
+          else
+            default_inspect(mod, fun_info)
+          end
+        _ ->
          default_inspect(mod, fun_info)
-        end
-
-      true ->
-        default_inspect(mod, fun_info)
+      end
    end
  end

  defp default_inspect(mod, fun_info) do
-    inspected_as_atom = Identifier.inspect_as_atom(mod)
-    extracted_name = extract_name(fun_info[:name])
-    "#Function<#{uniq(fun_info)}/#{fun_info[:arity]} in #{inspected_as_atom}#{extracted_name}>"
+    "#Function<#{uniq(fun_info)}/#{fun_info[:arity]} in " <>
+      "#{Inspect.Atom.inspect(mod)}#{extract_name(fun_info[:name])}>"
  end

  defp extract_name([]) do
@@ -338,17 +477,16 @@ defimpl Inspect, for: Function do
  end

  defp extract_name(name) do
-    case Identifier.extract_anonymous_fun_parent(name) do
-      {name, arity} ->
-        "." <> Identifier.inspect_as_function(name) <> "/" <> arity
-
-      :error ->
-        "." <> Identifier.inspect_as_function(name)
+    name = Atom.to_string(name)
+    case :binary.split(name, "-", [:global]) do
+      ["", name | _] -> "." <> name
+      _ -> "." <> name
    end
  end

  defp uniq(fun_info) do
-    Integer.to_string(fun_info[:new_index]) <> "." <> Integer.to_string(fun_info[:uniq])
+    Integer.to_string(fun_info[:new_index]) <> "." <>
+      Integer.to_string(fun_info[:uniq])
  end
 end

@@ -360,7 +498,7 @@ end

 defimpl Inspect, for: Port do
  def inspect(port, _opts) do
-    IO.iodata_to_binary(:erlang.port_to_list(port))
+    IO.iodata_to_binary :erlang.port_to_list(port)
  end
 end

@@ -372,19 +510,18 @@ defimpl Inspect, for: Reference do
 end

 defimpl Inspect, for: Any do
-  def inspect(%module{} = struct, opts) do
+  def inspect(%{__struct__: struct} = map, opts) do
    try do
-      module.__struct__
+      struct.__struct__
    rescue
-      _ -> Inspect.Map.inspect(struct, opts)
+      _ -> Inspect.Map.inspect(map, opts)
    else
      dunder ->
-        if :maps.keys(dunder) == :maps.keys(struct) do
-          pruned = :maps.remove(:__exception__, :maps.remove(:__struct__, struct))
-          colorless_opts = %{opts | syntax_colors: []}
-          Inspect.Map.inspect(pruned, Inspect.Atom.inspect(module, colorless_opts), opts)
+        if :maps.keys(dunder) == :maps.keys(map) do
+          pruned = :maps.remove(:__exception__, :maps.remove(:__struct__, map))
+          Inspect.Map.inspect(pruned, Inspect.Atom.inspect(struct, opts), opts)
        else
-          Inspect.Map.inspect(struct, opts)
+          Inspect.Map.inspect(map, opts)
        end
    end
  end
@@ -1,49 +1,33 @@
 defmodule Integer do
  @moduledoc """
  Functions for working with integers.
-
-  Some functions that work on integers are found in `Kernel`:
-
-    * `abs/2`
-    * `div/2`
-    * `max/2`
-    * `min/2`
-    * `rem/2`
-
  """

  import Bitwise

  @doc """
-  Determines if `integer` is odd.
+  Determines if an integer is odd.

-  Returns `true` if the given `integer` is an odd number,
-  otherwise it returns `false`.
+  Returns `true` if `n` is an odd number, otherwise `false`.

  Allowed in guard clauses.

  ## Examples

-      iex> Integer.is_odd(5)
+      iex> Integer.is_odd(3)
      true

-      iex> Integer.is_odd(6)
+      iex> Integer.is_odd(4)
      false
-
-      iex> Integer.is_odd(-5)
-      true
-
-      iex> Integer.is_odd(0)
-      false
-
  """
-  defguard is_odd(integer) when is_integer(integer) and (integer &&& 1) == 1
+  defmacro is_odd(n) do
+    quote do: (unquote(n) &&& 1) == 1
+  end

  @doc """
-  Determines if an `integer` is even.
+  Determines if an integer is even.

-  Returns `true` if the given `integer` is an even number,
-  otherwise it returns `false`.
+  Returns `true` if `n` is an even number, otherwise `false`.

  Allowed in guard clauses.

@@ -54,151 +38,72 @@ defmodule Integer do

      iex> Integer.is_even(5)
      false
-
-      iex> Integer.is_even(-10)
-      true
-
-      iex> Integer.is_even(0)
-      true
-
  """
-  defguard is_even(integer) when is_integer(integer) and (integer &&& 1) == 0
-
-  @doc """
-  Computes the modulo remainder of an integer division.
-
-  `Integer.mod/2` uses floored division, which means that
-  the result will always have the sign of the `divisor`.
-
-  Raises an `ArithmeticError` exception if one of the arguments is not an
-  integer, or when the `divisor` is `0`.
-
-  ## Examples
-
-      iex> Integer.mod(5, 2)
-      1
-      iex> Integer.mod(6, -4)
-      -2
-
-  """
-  @doc since: "1.4.0"
-  @spec mod(integer, neg_integer | pos_integer) :: integer
-  def mod(dividend, divisor) do
-    remainder = rem(dividend, divisor)
-
-    if remainder * divisor < 0 do
-      remainder + divisor
-    else
-      remainder
-    end
+  defmacro is_even(n) do
+    quote do: (unquote(n) &&& 1) == 0
  end

  @doc """
-  Performs a floored integer division.
+  Returns the ordered digits for the given non-negative integer.

-  Raises an `ArithmeticError` exception if one of the arguments is not an
-  integer, or when the `divisor` is `0`.
-
-  `Integer.floor_div/2` performs *floored* integer division. This means that
-  the result is always rounded towards negative infinity.
-
-  If you want to perform truncated integer division (rounding towards zero),
-  use `Kernel.div/2` instead.
+  An optional base value may be provided representing the radix for the returned
+  digits.

  ## Examples

-      iex> Integer.floor_div(5, 2)
-      2
-      iex> Integer.floor_div(6, -4)
-      -2
-      iex> Integer.floor_div(-99, 2)
-      -50
+      iex> Integer.digits(101)
+      [1, 0, 1]
+
+      iex> Integer.digits(58127, 2)
+      [1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1]

  """
-  @doc since: "1.4.0"
-  @spec floor_div(integer, neg_integer | pos_integer) :: integer
-  def floor_div(dividend, divisor) do
-    if dividend * divisor < 0 and rem(dividend, divisor) != 0 do
-      div(dividend, divisor) - 1
-    else
-      div(dividend, divisor)
-    end
+  @spec digits(non_neg_integer, pos_integer) :: [non_neg_integer]
+  def digits(n, base \\ 10) when is_integer(n)    and n >= 0
+                            and  is_integer(base) and base >= 2 do
+    do_digits(n, base, [])
+  end
+
+  defp do_digits(0, _base, []),  do: [0]
+  defp do_digits(0, _base, acc), do: acc
+  defp do_digits(n, base, acc)  do
+    do_digits div(n, base), base, [rem(n, base) | acc]
  end

  @doc """
-  Returns the ordered digits for the given `integer`.
+  Returns the integer represented by the ordered digits.

-  An optional `base` value may be provided representing the radix for the returned
-  digits. This one must be an integer >= 2.
+  An optional base value may be provided representing the radix for the digits.

  ## Examples

-      iex> Integer.digits(123)
-      [1, 2, 3]
-
-      iex> Integer.digits(170, 2)
-      [1, 0, 1, 0, 1, 0, 1, 0]
-
-      iex> Integer.digits(-170, 2)
-      [-1, 0, -1, 0, -1, 0, -1, 0]
-
-  """
-  @spec digits(integer, pos_integer) :: [integer, ...]
-  def digits(integer, base \\ 10)
-      when is_integer(integer) and is_integer(base) and base >= 2 do
-    do_digits(integer, base, [])
-  end
-
-  defp do_digits(integer, base, acc) when abs(integer) < base, do: [integer | acc]
-
-  defp do_digits(integer, base, acc),
-    do: do_digits(div(integer, base), base, [rem(integer, base) | acc])
-
-  @doc """
-  Returns the integer represented by the ordered `digits`.
-
-  An optional `base` value may be provided representing the radix for the `digits`.
-  Base has to be an integer greater or equal than `2`.
-
-  ## Examples
-
-      iex> Integer.undigits([1, 2, 3])
-      123
+      iex> Integer.undigits([1, 0, 1])
+      101

      iex> Integer.undigits([1, 4], 16)
      20
-
-      iex> Integer.undigits([])
-      0
-
  """
-  @spec undigits([integer], pos_integer) :: integer
-  def undigits(digits, base \\ 10) when is_list(digits) and is_integer(base) and base >= 2 do
+  @spec undigits([integer], integer) :: integer
+  def undigits(digits, base \\ 10) when is_integer(base) do
    do_undigits(digits, base, 0)
  end

  defp do_undigits([], _base, acc), do: acc
-
-  defp do_undigits([digit | _], base, _) when is_integer(digit) and digit >= base,
-    do: raise(ArgumentError, "invalid digit #{digit} in base #{base}")
-
-  defp do_undigits([digit | tail], base, acc) when is_integer(digit),
-    do: do_undigits(tail, base, acc * base + digit)
+  defp do_undigits([digit | tail], base, acc) do
+    do_undigits(tail, base, acc * base + digit)
+  end

  @doc """
-  Parses a text representation of an integer.
+  Converts a binary from a text representation of an integer
+  in an optional base `base` to the corresponding integer.

-  An optional `base` to the corresponding integer can be provided.
-  If `base` is not given, 10 will be used.
+  If the base `base` is not given, base 10 will be used.

-  If successful, returns a tuple in the form of `{integer, remainder_of_binary}`.
+  If successful, returns a tuple of the form `{integer, remainder_of_binary}`.
  Otherwise `:error`.

  Raises an error if `base` is less than 2 or more than 36.

-  If you want to convert a string-formatted integer directly to an integer,
-  `String.to_integer/1` or `String.to_integer/2` can be used instead.
-
  ## Examples

      iex> Integer.parse("34")
@@ -226,52 +131,73 @@ defmodule Integer do
      ** (ArgumentError) invalid base 38

  """
-  @spec parse(binary, 2..36) :: {integer, binary} | :error
+  @spec parse(binary, 2..36) :: {integer, binary} | :error | no_return
  def parse(binary, base \\ 10)

-  def parse(_binary, base) when base not in 2..36 do
-    raise ArgumentError, "invalid base #{inspect(base)}"
+  def parse(binary, base) when is_integer(base) and base in 2..36 do
+    parse_in_base(binary, base)
  end

-  def parse(binary, base) do
-    case count_digits(binary, base) do
-      0 ->
-        :error
+  def parse(_, base) do
+    raise ArgumentError, "invalid base #{base}"
+  end

-      count ->
-        {digits, rem} = :erlang.split_binary(binary, count)
-        {:erlang.binary_to_integer(digits, base), rem}
+  defp parse_in_base("-" <> bin, base) do
+    case do_parse(bin, base) do
+      :error -> :error
+      {number, remainder} -> {-number, remainder}
    end
  end

-  defp count_digits(<<sign, rest::binary>>, base) when sign in '+-' do
-    case count_digits_nosign(rest, base, 1) do
-      1 -> 0
-      count -> count
+  defp parse_in_base("+" <> bin, base) do
+    do_parse(bin, base)
+  end
+
+  defp parse_in_base(bin, base) when is_binary(bin) do
+    do_parse(bin, base)
+  end
+
+  defp do_parse(<<char, rest::binary>>, base) do
+    if valid_digit_in_base?(char, base) do
+      do_parse(rest, base, parse_digit(char, base))
+    else
+      :error
    end
  end

-  defp count_digits(<<rest::binary>>, base) do
-    count_digits_nosign(rest, base, 0)
-  end
+  defp do_parse(_, _), do: :error

-  digits = [{?0..?9, -?0}, {?A..?Z, 10 - ?A}, {?a..?z, 10 - ?a}]
-
-  for {chars, diff} <- digits,
-      char <- chars do
-    digit = char + diff
-
-    defp count_digits_nosign(<<unquote(char), rest::binary>>, base, count)
-         when base > unquote(digit) do
-      count_digits_nosign(rest, base, count + 1)
+  defp do_parse(<<char, rest::binary>> = bin, base, acc) do
+    if valid_digit_in_base?(char, base) do
+      do_parse(rest, base, base * acc + parse_digit(char, base))
+    else
+      {acc, bin}
    end
  end

-  defp count_digits_nosign(<<_::binary>>, _, count), do: count
+  defp do_parse(bitstring, _, acc) do
+    {acc, bitstring}
+  end
+
+  defp parse_digit(char, _) do
+    cond do
+      char in ?0..?9 -> char - ?0
+      char in ?A..?Z -> char - ?A + 10
+      true           -> char - ?a + 10
+    end
+  end
+
+  defp valid_digit_in_base?(char, base) do
+    if base <= 10 do
+      char in ?0..(?0 + base - 1)
+    else
+      char in ?0..?9 or char in ?A..(?A + base - 11) or char in ?a..(?a + base - 11)
+    end
+  end

  @doc """
  Returns a binary which corresponds to the text representation
-  of `integer`.
+  of `some_integer`.

  Inlined by the compiler.

@@ -280,26 +206,15 @@ defmodule Integer do
      iex> Integer.to_string(123)
      "123"

-      iex> Integer.to_string(+456)
-      "456"
-
-      iex> Integer.to_string(-789)
-      "-789"
-
-      iex> Integer.to_string(0123)
-      "123"
-
  """
-  @spec to_string(integer) :: String.t()
-  def to_string(integer) do
-    :erlang.integer_to_binary(integer)
+  @spec to_string(integer) :: String.t
+  def to_string(some_integer) do
+    :erlang.integer_to_binary(some_integer)
  end

  @doc """
  Returns a binary which corresponds to the text representation
-  of `integer` in the given `base`.
-
-  `base` can be an integer between 2 and 36.
+  of `some_integer` in base `base`.

  Inlined by the compiler.

@@ -308,114 +223,42 @@ defmodule Integer do
      iex> Integer.to_string(100, 16)
      "64"

-      iex> Integer.to_string(-100, 16)
-      "-64"
-
-      iex> Integer.to_string(882_681_651, 36)
-      "ELIXIR"
-
  """
-  @spec to_string(integer, 2..36) :: String.t()
-  def to_string(integer, base) do
-    :erlang.integer_to_binary(integer, base)
+  @spec to_string(integer, 2..36) :: String.t
+  def to_string(some_integer, base) do
+    :erlang.integer_to_binary(some_integer, base)
  end

  @doc """
-  Returns a charlist which corresponds to the text representation of the given `integer`.
+  Returns a char list which corresponds to the text representation of the given integer.

  Inlined by the compiler.

  ## Examples

-      iex> Integer.to_charlist(123)
-      '123'
-
-      iex> Integer.to_charlist(+456)
-      '456'
-
-      iex> Integer.to_charlist(-789)
-      '-789'
-
-      iex> Integer.to_charlist(0123)
-      '123'
+      iex> Integer.to_char_list(7)
+      '7'

  """
-  @spec to_charlist(integer) :: charlist
-  def to_charlist(integer) do
-    :erlang.integer_to_list(integer)
+  @spec to_char_list(integer) :: char_list
+  def to_char_list(number) do
+    :erlang.integer_to_list(number)
  end

  @doc """
-  Returns a charlist which corresponds to the text representation of `integer` in the given `base`.
-
-  `base` can be an integer between 2 and 36.
+  Returns a char list which corresponds to the text representation of the
+  given integer in the given base.

  Inlined by the compiler.

  ## Examples

-      iex> Integer.to_charlist(100, 16)
-      '64'
-
-      iex> Integer.to_charlist(-100, 16)
-      '-64'
-
-      iex> Integer.to_charlist(882_681_651, 36)
-      'ELIXIR'
+      iex> Integer.to_char_list(1023, 16)
+      '3FF'

  """
-  @spec to_charlist(integer, 2..36) :: charlist
-  def to_charlist(integer, base) do
-    :erlang.integer_to_list(integer, base)
+  @spec to_char_list(integer, 2..36) :: char_list
+  def to_char_list(number, base) do
+    :erlang.integer_to_list(number, base)
  end
-
-  @doc """
-  Returns the greatest common divisor of the two given integers.
-
-  The greatest common divisor (GCD) of `integer1` and `integer2` is the largest positive
-  integer that divides both `integer1` and `integer2` without leaving a remainder.
-
-  By convention, `gcd(0, 0)` returns `0`.
-
-  ## Examples
-
-      iex> Integer.gcd(2, 3)
-      1
-
-      iex> Integer.gcd(8, 12)
-      4
-
-      iex> Integer.gcd(8, -12)
-      4
-
-      iex> Integer.gcd(10, 0)
-      10
-
-      iex> Integer.gcd(7, 7)
-      7
-
-      iex> Integer.gcd(0, 0)
-      0
-
-  """
-  @doc since: "1.5.0"
-  @spec gcd(0, 0) :: 0
-  @spec gcd(integer, integer) :: pos_integer
-  def gcd(integer1, integer2) when is_integer(integer1) and is_integer(integer2) do
-    gcd_positive(abs(integer1), abs(integer2))
-  end
-
-  defp gcd_positive(0, integer2), do: integer2
-  defp gcd_positive(integer1, 0), do: integer1
-  defp gcd_positive(integer1, integer2), do: gcd_positive(integer2, rem(integer1, integer2))
-
-  # TODO: Remove by 2.0
-  @doc false
-  @deprecated "Use Integer.to_charlist/1 instead"
-  def to_char_list(integer), do: Integer.to_charlist(integer)
-
-  # TODO: Remove by 2.0
-  @doc false
-  @deprecated "Use Integer.to_charlist/2 instead"
-  def to_char_list(integer, base), do: Integer.to_charlist(integer, base)
 end
@@ -1,25 +1,25 @@
 defmodule IO do
  @moduledoc """
-  Functions handling input/output (IO).
+  Functions handling IO.

  Many functions in this module expect an IO device as an argument.
-  An IO device must be a PID or an atom representing a process.
+  An IO device must be a pid or an atom representing a process.
  For convenience, Elixir provides `:stdio` and `:stderr` as
  shortcuts to Erlang's `:standard_io` and `:standard_error`.

-  The majority of the functions expect chardata, i.e. strings or
+  The majority of the functions expect char data, i.e. strings or
  lists of characters and strings. In case another type is given,
  functions will convert to string via the `String.Chars` protocol
  (as shown in typespecs).

-  The functions starting with `bin` expect iodata as an argument,
+  The functions starting with `bin*` expect iodata as an argument,
  i.e. binaries or lists of bytes and binaries.

  ## IO devices

-  An IO device may be an atom or a PID. In case it is an atom,
+  An IO device may be an atom or a pid. In case it is an atom,
  the atom must be the name of a registered process. In addition,
-  Elixir provides two shortcuts:
+  Elixir provides two shorcuts:

    * `:stdio` - a shortcut for `:standard_io`, which maps to
      the current `Process.group_leader/0` in Erlang
@@ -27,9 +27,9 @@ defmodule IO do
    * `:stderr` - a shortcut for the named process `:standard_error`
      provided in Erlang

-  IO devices maintain their position, which means subsequent calls to any
-  reading or writing functions will start from the place where the device
-  was last accessed. The position of files can be changed using the
+  IO devices maintain their position, that means subsequent calls to any
+  reading or writing functions will start from the place when the device
+  was last accessed. Position of files can be changed using the
  `:file.position/2` function.

  """
@@ -38,6 +38,8 @@ defmodule IO do
  @type nodata :: {:error, term} | :eof
  @type chardata() :: :unicode.chardata()

+  import :erlang, only: [group_leader: 0]
+
  defmacrop is_iodata(data) do
    quote do
      is_list(unquote(data)) or is_binary(unquote(data))
@@ -45,15 +47,12 @@ defmodule IO do
  end

  @doc """
-  Reads from the IO `device`.
-
-  The `device` is iterated by the given number of characters or line by line if
-  `:line` is given.
-  Alternatively, if `:all` is given, then whole `device` is returned.
+  Reads `count` characters from the IO device, a whole
+  `:line` or the whole device with `:all`.

  It returns:

-    * `data` - the output characters
+    * `data` - the input characters

    * `:eof` - end of file was encountered

@@ -65,7 +64,7 @@ defmodule IO do
  empty string in case the device has reached EOF.
  """
  @spec read(device, :all | :line | non_neg_integer) :: chardata | nodata
-  def read(device \\ :stdio, line_or_chars)
+  def read(device \\ group_leader, chars_or_line)

  def read(device, :all) do
    do_read_all(map_dev(device), "")
@@ -75,7 +74,7 @@ defmodule IO do
    :io.get_line(map_dev(device), '')
  end

-  def read(device, count) when is_integer(count) and count >= 0 do
+  def read(device, count) when count >= 0 do
    :io.get_chars(map_dev(device), '', count)
  end

@@ -88,15 +87,12 @@ defmodule IO do
  end

  @doc """
-  Reads from the IO `device`. The operation is Unicode unsafe.
-
-  The `device` is iterated by the given number of bytes or line by line if
-  `:line` is given.
-  Alternatively, if `:all` is given, then whole `device` is returned.
+  Reads `count` characters from the IO device, a whole
+  `:line` or the whole device with `:all`.

  It returns:

-    * `data` - the output bytes
+    * `data` - the input characters

    * `:eof` - end of file was encountered

@@ -107,11 +103,11 @@ defmodule IO do
  If `:all` is given, `:eof` is never returned, but an
  empty string in case the device has reached EOF.

-  Note: do not use this function on IO devices in Unicode mode
+  Note: do not use this function on IO devices in unicode mode
  as it will return the wrong result.
  """
  @spec binread(device, :all | :line | non_neg_integer) :: iodata | nodata
-  def binread(device \\ :stdio, line_or_chars)
+  def binread(device \\ group_leader, chars_or_line)

  def binread(device, :all) do
    do_binread_all(map_dev(device), "")
@@ -124,7 +120,7 @@ defmodule IO do
    end
  end

-  def binread(device, count) when is_integer(count) and count >= 0 do
+  def binread(device, count) when count >= 0 do
    case :file.read(map_dev(device), count) do
      {:ok, data} -> data
      other -> other
@@ -141,205 +137,87 @@ defmodule IO do
  end

  @doc """
-  Writes `item` to the given `device`.
-
-  By default, the `device` is the standard output.
-
-  ## Examples
-
-      IO.write "sample"
-      #=> sample
-
-      IO.write :stderr, "error"
-      #=> error
-
-  """
-  @spec write(device, chardata | String.Chars.t()) :: :ok
-  def write(device \\ :stdio, item) do
-    :io.put_chars(map_dev(device), to_chardata(item))
-  end
-
-  @doc """
-  Writes `item` as a binary to the given `device`.
-  No Unicode conversion happens.
-  The operation is Unicode unsafe.
-
-  Check `write/2` for more information.
-
-  Note: do not use this function on IO devices in Unicode mode
-  as it will return the wrong result.
-  """
-  @spec binwrite(device, iodata) :: :ok | {:error, term}
-  def binwrite(device \\ :stdio, item) when is_iodata(item) do
-    :file.write(map_dev(device), item)
-  end
-
-  @doc """
-  Writes `item` to the given `device`, similar to `write/2`,
-  but adds a newline at the end.
-
-  By default, the `device` is the standard output. It returns `:ok`
-  if it succeeds.
-
-  ## Examples
-
-      IO.puts "Hello World!"
-      #=> Hello World!
-
-      IO.puts :stderr, "error"
-      #=> error
-
-  """
-  @spec puts(device, chardata | String.Chars.t()) :: :ok
-  def puts(device \\ :stdio, item) do
-    :io.put_chars(map_dev(device), [to_chardata(item), ?\n])
-  end
-
-  @doc """
-  Writes a `message` to stderr, along with the given `stacktrace`.
-
-  This function also notifies the compiler a warning was printed
-  (in case --warnings-as-errors was enabled). It returns `:ok`
-  if it succeeds.
-
-  An empty list can be passed to avoid stacktrace printing.
-
-  ## Examples
-
-      stacktrace = [{MyApp, :main, 1, [file: 'my_app.ex', line: 4]}]
-      IO.warn "variable bar is unused", stacktrace
-      #=> warning: variable bar is unused
-      #=>   my_app.ex:4: MyApp.main/1
-
-  """
-  @spec warn(chardata | String.Chars.t(), Exception.stacktrace()) :: :ok
-  def warn(message, []) do
-    :elixir_errors.bare_warn(nil, nil, [to_chardata(message), ?\n])
-  end
-
-  def warn(message, [{_, _, _, opts} | _] = stacktrace) do
-    formatted_trace = Enum.map_join(stacktrace, "\n  ", &Exception.format_stacktrace_entry(&1))
-    message = [to_chardata(message), ?\n, "  ", formatted_trace, ?\n]
-    line = opts[:line]
-    file = opts[:file]
-    :elixir_errors.bare_warn(line, file && List.to_string(file), message)
-  end
-
-  @doc """
-  Writes a `message` to stderr, along with the current stacktrace.
+  Writes the given argument to the given device.

+  By default the device is the standard output.
  It returns `:ok` if it succeeds.

  ## Examples

-      IO.warn "variable bar is unused"
-      #=> warning: variable bar is unused
-      #=>   (iex) evaluator.ex:108: IEx.Evaluator.eval/4
+      IO.write "sample"
+      #=> "sample"
+
+      IO.write :stderr, "error"
+      #=> "error"

  """
-  @spec warn(chardata | String.Chars.t()) :: :ok
-  def warn(message) do
-    {:current_stacktrace, stacktrace} = Process.info(self(), :current_stacktrace)
-    warn(message, Enum.drop(stacktrace, 2))
+  @spec write(device, chardata | String.Chars.t) :: :ok
+  def write(device \\ group_leader(), item) do
+    :io.put_chars map_dev(device), to_chardata(item)
  end

  @doc """
-  Inspects and writes the given `item` to the device.
+  Writes the given argument to the given device
+  as a binary, no unicode conversion happens.

-  It's important to note that it returns the given `item` unchanged.
-  This makes it possible to "spy" on values by inserting an
-  `IO.inspect/2` call almost anywhere in your code, for example,
-  in the middle of a pipeline.
+  Check `write/2` for more information.
+
+  Note: do not use this function on IO devices in unicode mode
+  as it will return the wrong result.
+  """
+  @spec binwrite(device, iodata) :: :ok | {:error, term}
+  def binwrite(device \\ group_leader(), item) when is_iodata(item) do
+    :file.write map_dev(device), item
+  end
+
+  @doc """
+  Writes the argument to the device, similar to `write/2`,
+  but adds a newline at the end. The argument is expected
+  to be a chardata.
+  """
+  @spec puts(device, chardata | String.Chars.t) :: :ok
+  def puts(device \\ group_leader(), item) do
+    erl_dev = map_dev(device)
+    :io.put_chars erl_dev, [to_chardata(item), ?\n]
+  end
+
+  @doc """
+  Inspects and writes the given argument to the device.

  It enables pretty printing by default with width of
  80 characters. The width can be changed by explicitly
  passing the `:width` option.

-  The output can be decorated with a label, by providing the `:label`
-  option to easily distinguish it from other `IO.inspect/2` calls.
-  The label will be printed before the inspected `item`.
-
-  See `Inspect.Opts` for a full list of remaining formatting options.
+  See `Inspect.Opts` for a full list of options.

  ## Examples

-      IO.inspect <<0, 1, 2>>, width: 40
-
-  Prints:
-
-      <<0, 1, 2>>
-
-  We can use the `:label` option to decorate the output:
-
-      IO.inspect 1..100, label: "a wonderful range"
-
-  Prints:
-
-      a wonderful range: 1..100
-
-  The `:label` option is especially useful with pipelines:
-
-      [1, 2, 3]
-      |> IO.inspect(label: "before")
-      |> Enum.map(&(&1 * 2))
-      |> IO.inspect(label: "after")
-      |> Enum.sum
-
-  Prints:
-
-      before: [1, 2, 3]
-      after: [2, 4, 6]
+      IO.inspect Process.list, width: 40

  """
-  @spec inspect(item, keyword) :: item when item: var
+  @spec inspect(item, Keyword.t) :: item when item: var
  def inspect(item, opts \\ []) do
-    inspect(:stdio, item, opts)
+    inspect group_leader(), item, opts
  end

  @doc """
-  Inspects `item` according to the given options using the IO `device`.
+  Inspects the item with options using the given device.

-  See `inspect/2` for a full list of options.
+  See `Inspect.Opts` for a full list of options.
  """
-  @spec inspect(device, item, keyword) :: item when item: var
+  @spec inspect(device, item, Keyword.t) :: item when item: var
  def inspect(device, item, opts) when is_list(opts) do
-    label = if label = opts[:label], do: [to_chardata(label), ": "], else: []
-    opts = struct(Inspect.Opts, opts)
-    doc = Inspect.Algebra.group(Inspect.Algebra.to_doc(item, opts))
-    chardata = Inspect.Algebra.format(doc, opts.width)
-    puts(device, [label, chardata])
+    opts   = struct(Inspect.Opts, opts)
+    iodata = Inspect.Algebra.format(Inspect.Algebra.to_doc(item, opts), opts.width)
+    puts device, iodata
    item
  end

  @doc """
-  Gets a number of bytes from IO device `:stdio`.
-
-  If `:stdio` is a Unicode device, `count` implies
-  the number of Unicode codepoints to be retrieved.
+  Gets a number of bytes from the io device. If the
+  io device is a unicode device, `count` implies
+  the number of unicode codepoints to be retrieved.
  Otherwise, `count` is the number of raw bytes to be retrieved.
-
-  See `IO.getn/3` for a description of return values.
-
-  """
-  @spec getn(chardata | String.Chars.t(), pos_integer) :: chardata | nodata
-  @spec getn(device, chardata | String.Chars.t()) :: chardata | nodata
-  def getn(prompt, count \\ 1)
-
-  def getn(prompt, count) when is_integer(count) and count > 0 do
-    getn(:stdio, prompt, count)
-  end
-
-  def getn(device, prompt) when not is_integer(prompt) do
-    getn(device, prompt, 1)
-  end
-
-  @doc """
-  Gets a number of bytes from the IO `device`.
-
-  If the IO `device` is a Unicode device, `count` implies
-  the number of Unicode codepoints to be retrieved.
-  Otherwise, `count` is the number of raw bytes to be retrieved.
-
  It returns:

    * `data` - the input characters
@@ -349,15 +227,32 @@ defmodule IO do
    * `{:error, reason}` - other (rare) error condition;
      for instance, `{:error, :estale}` if reading from an
      NFS volume
-
  """
-  @spec getn(device, chardata | String.Chars.t(), pos_integer) :: chardata | nodata
-  def getn(device, prompt, count) when is_integer(count) and count > 0 do
+  @spec getn(chardata | String.Chars.t, pos_integer) :: chardata | nodata
+  @spec getn(device, chardata | String.Chars.t) :: chardata | nodata
+  def getn(prompt, count \\ 1)
+
+  def getn(prompt, count) when is_integer(count) do
+    getn(group_leader, prompt, count)
+  end
+
+  def getn(device, prompt) do
+    getn(device, prompt, 1)
+  end
+
+  @doc """
+  Gets a number of bytes from the io device. If the
+  io device is a unicode device, `count` implies
+  the number of unicode codepoints to be retrieved.
+  Otherwise, `count` is the number of raw bytes to be retrieved.
+  """
+  @spec getn(device, chardata | String.Chars.t, pos_integer) :: chardata | nodata
+  def getn(device, prompt, count) do
    :io.get_chars(map_dev(device), to_chardata(prompt), count)
  end

-  @doc ~S"""
-  Reads a line from the IO `device`.
+  @doc """
+  Reads a line from the IO device.

  It returns:

@@ -374,25 +269,24 @@ defmodule IO do

  To display "What is your name?" as a prompt and await user input:

-      IO.gets "What is your name?\n"
-
+      IO.gets "What is your name?"
  """
-  @spec gets(device, chardata | String.Chars.t()) :: chardata | nodata
-  def gets(device \\ :stdio, prompt) do
+  @spec gets(device, chardata | String.Chars.t) :: chardata | nodata
+  def gets(device \\ group_leader(), prompt) do
    :io.get_line(map_dev(device), to_chardata(prompt))
  end

  @doc """
-  Converts the IO `device` into an `IO.Stream`.
+  Converts the io device into a `IO.Stream`.

  An `IO.Stream` implements both `Enumerable` and
  `Collectable`, allowing it to be used for both read
  and write.

-  The `device` is iterated by the given number of characters or line by line if
-  `:line` is given.
+  The device is iterated line by line if `:line` is given or
+  by a given number of codepoints.

-  This reads from the IO as UTF-8. Check out
+  This reads the IO as utf-8. Check out
  `IO.binstream/2` to handle the IO as a raw binary.

  Note that an IO stream has side effects and every time
@@ -406,35 +300,29 @@ defmodule IO do
      Enum.each IO.stream(:stdio, :line), &IO.write(&1)

  """
-  @spec stream(device, :line | pos_integer) :: Enumerable.t()
-  def stream(device, line_or_codepoints)
-      when line_or_codepoints == :line
-      when is_integer(line_or_codepoints) and line_or_codepoints > 0 do
+  @spec stream(device, :line | pos_integer) :: Enumerable.t
+  def stream(device, line_or_codepoints) do
    IO.Stream.__build__(map_dev(device), false, line_or_codepoints)
  end

  @doc """
-  Converts the IO `device` into an `IO.Stream`. The operation is Unicode unsafe.
+  Converts the IO device into a `IO.Stream`.

  An `IO.Stream` implements both `Enumerable` and
  `Collectable`, allowing it to be used for both read
  and write.

-  The `device` is iterated by the given number of bytes or line by line if
-  `:line` is given.
-  This reads from the IO device as a raw binary.
+  The device is iterated line by line or by a number of bytes.
+  This reads the IO device as a raw binary.

  Note that an IO stream has side effects and every time
  you go over the stream you may get different results.

-  Finally, do not use this function on IO devices in Unicode
+  Finally, do not use this function on IO devices in unicode
  mode as it will return the wrong result.
-
  """
-  @spec binstream(device, :line | pos_integer) :: Enumerable.t()
-  def binstream(device, line_or_bytes)
-      when line_or_bytes == :line
-      when is_integer(line_or_bytes) and line_or_bytes > 0 do
+  @spec binstream(device, :line | pos_integer) :: Enumerable.t
+  def binstream(device, line_or_bytes) do
    IO.Stream.__build__(map_dev(device), true, line_or_bytes)
  end

@@ -442,8 +330,8 @@ defmodule IO do
  Converts chardata (a list of integers representing codepoints,
  lists and strings) into a string.

-  In case the conversion fails, it raises an `UnicodeConversionError`.
-  If a string is given, it returns the string itself.
+  In case the conversion fails, it raises a `UnicodeConversionError`.
+  If a string is given, returns the string itself.

  ## Examples

@@ -453,27 +341,32 @@ defmodule IO do
      iex> IO.chardata_to_string([0x0061, "bc"])
      "abc"

-      iex> IO.chardata_to_string("string")
-      "string"
-
  """
-  @spec chardata_to_string(chardata) :: String.t() | no_return
+  @spec chardata_to_string(chardata) :: String.t | no_return
  def chardata_to_string(string) when is_binary(string) do
    string
  end

  def chardata_to_string(list) when is_list(list) do
-    List.to_string(list)
+    case :unicode.characters_to_binary(list) do
+      result when is_binary(result) ->
+        result
+
+      {:error, encoded, rest} ->
+        raise UnicodeConversionError, encoded: encoded, rest: rest, kind: :invalid
+
+      {:incomplete, encoded, rest} ->
+        raise UnicodeConversionError, encoded: encoded, rest: rest, kind: :incomplete
+    end
  end

  @doc """
  Converts iodata (a list of integers representing bytes, lists
  and binaries) into a binary.
-  The operation is Unicode unsafe.

  Notice that this function treats lists of integers as raw bytes
  and does not perform any kind of encoding conversion. If you want
-  to convert from a charlist to a string (UTF-8 encoded), please
+  to convert from a char list to a string (UTF-8 encoded), please
  use `chardata_to_string/1` instead.

  If this function receives a binary, the same binary is returned.
@@ -485,7 +378,7 @@ defmodule IO do
      iex> bin1 = <<1, 2, 3>>
      iex> bin2 = <<4, 5>>
      iex> bin3 = <<6>>
-      iex> IO.iodata_to_binary([bin1, 1, [2, 3, bin2], 4 | bin3])
+      iex> IO.iodata_to_binary([bin1, 1, [2, 3, bin2], 4|bin3])
      <<1, 2, 3, 1, 2, 3, 4, 5, 4, 6>>

      iex> bin = <<1, 2, 3>>
@@ -505,7 +398,7 @@ defmodule IO do

  ## Examples

-      iex> IO.iodata_length([1, 2 | <<3, 4>>])
+      iex> IO.iodata_length([1, 2|<<3, 4>>])
      4

  """
@@ -515,28 +408,24 @@ defmodule IO do
  end

  @doc false
-  def each_stream(device, line_or_codepoints) do
-    case read(device, line_or_codepoints) do
+  def each_stream(device, what) do
+    case read(device, what) do
      :eof ->
        {:halt, device}
-
      {:error, reason} ->
        raise IO.StreamError, reason: reason
-
      data ->
        {[data], device}
    end
  end

  @doc false
-  def each_binstream(device, line_or_chars) do
-    case binread(device, line_or_chars) do
+  def each_binstream(device, what) do
+    case binread(device, what) do
      :eof ->
        {:halt, device}
-
      {:error, reason} ->
        raise IO.StreamError, reason: reason
-
      data ->
        {[data], device}
    end
@@ -544,8 +433,8 @@ defmodule IO do

  @compile {:inline, map_dev: 1, to_chardata: 1}

-  # Map the Elixir names for standard IO and error to Erlang names
-  defp map_dev(:stdio), do: :standard_io
+  # Map the Elixir names for standard io and error to Erlang names
+  defp map_dev(:stdio),  do: :standard_io
  defp map_dev(:stderr), do: :standard_error
  defp map_dev(other) when is_atom(other) or is_pid(other) or is_tuple(other), do: other

@@ -25,10 +25,9 @@ defmodule IO.ANSI do

  import IO.ANSI.Sequence

-  @type ansicode :: atom
-  @type ansilist ::
-          maybe_improper_list(char | ansicode | binary | ansilist, binary | ansicode | [])
-  @type ansidata :: ansilist | ansicode | binary
+  @typep ansicode :: atom()
+  @typep ansilist :: maybe_improper_list(char() | ansicode() | binary() | ansilist(), binary() | ansicode() | [])
+  @type  ansidata :: ansilist() | ansicode() | binary()

  @doc """
  Checks if ANSI coloring is supported and enabled on this machine.
@@ -43,8 +42,8 @@ defmodule IO.ANSI do
    Application.get_env(:elixir, :ansi_enabled, false)
  end

-  @doc "Sets foreground color."
-  @spec color(0..255) :: String.t()
+  @doc "Sets foreground color"
+  @spec color(0..255) :: String.t
  def color(code) when code in 0..255, do: "\e[38;5;#{code}m"

  @doc ~S"""
@@ -52,13 +51,13 @@ defmodule IO.ANSI do

  Valid values for each color are in the range 0 to 5.
  """
-  @spec color(0..5, 0..5, 0..5) :: String.t()
+  @spec color(0..5, 0..5, 0..5) :: String.t
  def color(r, g, b) when r in 0..5 and g in 0..5 and b in 0..5 do
-    color(16 + 36 * r + 6 * g + b)
+    color(16 + (36 * r) + (6 * g) + b)
  end

-  @doc "Sets background color."
-  @spec color_background(0..255) :: String.t()
+  @doc "Sets background color"
+  @spec color_background(0..255) :: String.t
  def color_background(code) when code in 0..255, do: "\e[48;5;#{code}m"

  @doc ~S"""
@@ -66,145 +65,106 @@ defmodule IO.ANSI do

  Valid values for each color are in the range 0 to 5.
  """
-  @spec color_background(0..5, 0..5, 0..5) :: String.t()
+  @spec color_background(0..5, 0..5, 0..5) :: String.t
  def color_background(r, g, b) when r in 0..5 and g in 0..5 and b in 0..5 do
-    color_background(16 + 36 * r + 6 * g + b)
+    color_background(16 + (36 * r) + (6 * g) + b)
  end

-  @doc "Resets all attributes."
-  defsequence(:reset, 0)
+  @doc "Resets all attributes"
+  defsequence :reset, 0

-  @doc "Bright (increased intensity) or bold."
-  defsequence(:bright, 1)
+  @doc "Bright (increased intensity) or Bold"
+  defsequence :bright, 1

-  @doc "Faint (decreased intensity). Not widely supported."
-  defsequence(:faint, 2)
+  @doc "Faint (decreased intensity), not widely supported"
+  defsequence :faint, 2

-  @doc "Italic: on. Not widely supported. Sometimes treated as inverse."
-  defsequence(:italic, 3)
+  @doc "Italic: on. Not widely supported. Sometimes treated as inverse"
+  defsequence :italic, 3

-  @doc "Underline: single."
-  defsequence(:underline, 4)
+  @doc "Underline: Single"
+  defsequence :underline, 4

-  @doc "Blink: slow. Less than 150 per minute."
-  defsequence(:blink_slow, 5)
+  @doc "Blink: Slow. Less than 150 per minute"
+  defsequence :blink_slow, 5

-  @doc "Blink: rapid. MS-DOS ANSI.SYS; 150 per minute or more; not widely supported."
-  defsequence(:blink_rapid, 6)
+  @doc "Blink: Rapid. MS-DOS ANSI.SYS; 150 per minute or more; not widely supported"
+  defsequence :blink_rapid, 6

-  @doc "Image: negative. Swap foreground and background."
-  defsequence(:inverse, 7)
+  @doc "Image: Negative. Swap foreground and background"
+  defsequence :inverse, 7

-  @doc "Image: negative. Swap foreground and background."
-  defsequence(:reverse, 7)
+  @doc "Image: Negative. Swap foreground and background"
+  defsequence :reverse, 7

-  @doc "Conceal. Not widely supported."
-  defsequence(:conceal, 8)
+  @doc "Conceal. Not widely supported"
+  defsequence :conceal, 8

-  @doc "Crossed-out. Characters legible, but marked for deletion. Not widely supported."
-  defsequence(:crossed_out, 9)
+  @doc "Crossed-out. Characters legible, but marked for deletion. Not widely supported"
+  defsequence :crossed_out, 9

-  @doc "Sets primary (default) font."
-  defsequence(:primary_font, 10)
+  @doc "Sets primary (default) font"
+  defsequence :primary_font, 10

  for font_n <- [1, 2, 3, 4, 5, 6, 7, 8, 9] do
-    @doc "Sets alternative font #{font_n}."
-    defsequence(:"font_#{font_n}", font_n + 10)
+    @doc "Sets alternative font #{font_n}"
+    defsequence :"font_#{font_n}", font_n + 10
  end

-  @doc "Normal color or intensity."
-  defsequence(:normal, 22)
+  @doc "Normal color or intensity"
+  defsequence :normal, 22

-  @doc "Not italic."
-  defsequence(:not_italic, 23)
+  @doc "Not italic"
+  defsequence :not_italic, 23

-  @doc "Underline: none."
-  defsequence(:no_underline, 24)
+  @doc "Underline: None"
+  defsequence :no_underline, 24

-  @doc "Blink: off."
-  defsequence(:blink_off, 25)
-
-  @doc "Image: positive. Normal foreground and background."
-  defsequence(:inverse_off, 27)
-
-  @doc "Image: positive. Normal foreground and background."
-  defsequence(:reverse_off, 27)
+  @doc "Blink: off"
+  defsequence :blink_off, 25

  colors = [:black, :red, :green, :yellow, :blue, :magenta, :cyan, :white]

  for {color, code} <- Enum.with_index(colors) do
-    @doc "Sets foreground color to #{color}."
-    defsequence(color, code + 30)
+    @doc "Sets foreground color to #{color}"
+    defsequence color, code + 30

-    @doc "Sets foreground color to light #{color}."
-    defsequence(:"light_#{color}", code + 90)
-
-    @doc "Sets background color to #{color}."
-    defsequence(:"#{color}_background", code + 40)
-
-    @doc "Sets background color to light #{color}."
-    defsequence(:"light_#{color}_background", code + 100)
+    @doc "Sets background color to #{color}"
+    defsequence :"#{color}_background", code + 40
  end

-  @doc "Default text color."
-  defsequence(:default_color, 39)
+  @doc "Default text color"
+  defsequence :default_color, 39

-  @doc "Default background color."
-  defsequence(:default_background, 49)
+  @doc "Default background color"
+  defsequence :default_background, 49

-  @doc "Framed."
-  defsequence(:framed, 51)
+  @doc "Framed"
+  defsequence :framed, 51

-  @doc "Encircled."
-  defsequence(:encircled, 52)
+  @doc "Encircled"
+  defsequence :encircled, 52

-  @doc "Overlined."
-  defsequence(:overlined, 53)
+  @doc "Overlined"
+  defsequence :overlined, 53

-  @doc "Not framed or encircled."
-  defsequence(:not_framed_encircled, 54)
+  @doc "Not framed or encircled"
+  defsequence :not_framed_encircled, 54

-  @doc "Not overlined."
-  defsequence(:not_overlined, 55)
+  @doc "Not overlined"
+  defsequence :not_overlined, 55

-  @doc "Sends cursor home."
-  defsequence(:home, "", "H")
+  @doc "Sends cursor home"
+  defsequence :home, "", "H"

-  @doc """
-  Sends cursor to the absolute position specified by `line` and `column`.
+  @doc "Clears screen"
+  defsequence :clear, "2", "J"

-  Line `0` and column `0` would mean the top left corner.
-  """
-  @spec cursor(non_neg_integer, non_neg_integer) :: String.t()
-  def cursor(line, column)
-      when is_integer(line) and line >= 0 and is_integer(column) and column >= 0 do
-    "\e[#{line};#{column}H"
-  end
-
-  @doc "Sends cursor `lines` up."
-  @spec cursor_up(pos_integer) :: String.t()
-  def cursor_up(lines \\ 1) when is_integer(lines) and lines >= 1, do: "\e[#{lines}A"
-
-  @doc "Sends cursor `lines` down."
-  @spec cursor_down(pos_integer) :: String.t()
-  def cursor_down(lines \\ 1) when is_integer(lines) and lines >= 1, do: "\e[#{lines}B"
-
-  @doc "Sends cursor `columns` to the right."
-  @spec cursor_right(pos_integer) :: String.t()
-  def cursor_right(columns \\ 1) when is_integer(columns) and columns >= 1, do: "\e[#{columns}C"
-
-  @doc "Sends cursor `columns` to the left."
-  @spec cursor_left(pos_integer) :: String.t()
-  def cursor_left(columns \\ 1) when is_integer(columns) and columns >= 1, do: "\e[#{columns}D"
-
-  @doc "Clears screen."
-  defsequence(:clear, "2", "J")
-
-  @doc "Clears line."
-  defsequence(:clear_line, "2", "K")
+  @doc "Clears line"
+  defsequence :clear_line, "2", "K"

  defp format_sequence(other) do
-    raise ArgumentError, "invalid ANSI sequence specification: #{inspect(other)}"
+    raise ArgumentError, "invalid ANSI sequence specification: #{inspect other}"
  end

  @doc ~S"""
@@ -226,8 +186,8 @@ defmodule IO.ANSI do
      [[[[[[], "Hello, "] | "\e[31m"] | "\e[1m"], "world!"] | "\e[0m"]

  """
-  def format(chardata, emit? \\ enabled?()) when is_boolean(emit?) do
-    do_format(chardata, [], [], emit?, :maybe)
+  def format(chardata, emit \\ enabled?) when is_boolean(emit) do
+    do_format(chardata, [], [], emit, :maybe)
  end

  @doc ~S"""
@@ -246,12 +206,12 @@ defmodule IO.ANSI do
      [[[[[[] | "\e[1m"], 87], 111], 114], 100]

  """
-  def format_fragment(chardata, emit? \\ enabled?()) when is_boolean(emit?) do
-    do_format(chardata, [], [], emit?, false)
+  def format_fragment(chardata, emit \\ enabled?) when is_boolean(emit) do
+    do_format(chardata, [], [], emit, false)
  end

-  defp do_format([term | rest], rem, acc, emit?, append_reset) do
-    do_format(term, [rest | rem], acc, emit?, append_reset)
+  defp do_format([term | rest], rem, acc, emit, append_reset) do
+    do_format(term, [rest | rem], acc, emit, append_reset)
  end

  defp do_format(term, rem, acc, true, append_reset) when is_atom(term) do
@@ -262,19 +222,19 @@ defmodule IO.ANSI do
    do_format([], rem, acc, false, append_reset)
  end

-  defp do_format(term, rem, acc, emit?, append_reset) when not is_list(term) do
-    do_format([], rem, [acc, term], emit?, append_reset)
+  defp do_format(term, rem, acc, emit, append_reset) when not is_list(term) do
+    do_format([], rem, [acc | [term]], emit, append_reset)
  end

-  defp do_format([], [next | rest], acc, emit?, append_reset) do
-    do_format(next, rest, acc, emit?, append_reset)
+  defp do_format([], [next | rest], acc, emit, append_reset) do
+    do_format(next, rest, acc, emit, append_reset)
  end

  defp do_format([], [], acc, true, true) do
-    [acc | IO.ANSI.reset()]
+    [acc | IO.ANSI.reset]
  end

-  defp do_format([], [], acc, _emit?, _append_reset) do
+  defp do_format([], [], acc, _emit, _append_reset) do
    acc
  end
 end
@@ -2,41 +2,35 @@ defmodule IO.ANSI.Docs do
  @moduledoc false

  @bullets [?*, ?-, ?+]
-  @spaces [" ", "\n", "\t"]

  @doc """
  The default options used by this module.

-  The supported keys are:
+  The supported values are:

    * `:enabled`           - toggles coloring on and off (true)
    * `:doc_bold`          - bold text (bright)
-    * `:doc_code`          - code blocks (cyan)
-    * `:doc_headings`      - h1, h2, h3, h4, h5, h6 headings (yellow)
-    * `:doc_metadata`      - documentation metadata keys (yellow)
+    * `:doc_code`          - code blocks (cyan, bright)
+    * `:doc_headings`      - h1 and h2 headings (yellow, bright)
    * `:doc_inline_code`   - inline code (cyan)
-    * `:doc_table_heading` - the style for table headings
-    * `:doc_title`         - top level heading (reverse, yellow)
+    * `:doc_table_heading` - style for table headings
+    * `:doc_title`         - top level heading (reverse, yellow, bright)
    * `:doc_underline`     - underlined text (underline)
    * `:width`             - the width to format the text (80)

  Values for the color settings are strings with
  comma-separated ANSI values.
  """
-  @spec default_options() :: keyword
  def default_options do
-    [
-      enabled: true,
-      doc_bold: [:bright],
-      doc_code: [:cyan],
-      doc_headings: [:yellow],
-      doc_metadata: [:yellow],
-      doc_inline_code: [:cyan],
-      doc_table_heading: [:reverse],
-      doc_title: [:reverse, :yellow],
-      doc_underline: [:underline],
-      width: 80
-    ]
+    [enabled:           true,
+     doc_bold:          [:bright],
+     doc_code:          [:cyan, :bright],
+     doc_headings:      [:yellow],
+     doc_inline_code:   [:cyan],
+     doc_table_heading: [:reverse],
+     doc_title:         [:reverse, :yellow],
+     doc_underline:     [:underline],
+     width:             80]
  end

  @doc """
@@ -44,63 +38,27 @@ defmodule IO.ANSI.Docs do

  See `default_options/0` for docs on the supported options.
  """
-  @spec print_heading(String.t(), keyword) :: :ok
  def print_heading(heading, options \\ []) do
-    IO.puts(IO.ANSI.reset())
-    options = Keyword.merge(default_options(), options)
-    width = options[:width]
+    IO.puts IO.ANSI.reset
+    options = Keyword.merge(default_options, options)
+    width   = options[:width]
    padding = div(width + String.length(heading), 2)
-    heading = heading |> String.pad_leading(padding) |> String.pad_trailing(width)
+    heading = heading |> String.rjust(padding) |> String.ljust(width)
    write(:doc_title, heading, options)
-    newline_after_block()
-  end
-
-  @doc """
-  Prints documentation metadata (only `since` and `deprecated` for now).
-
-  See `default_options/0` for docs on the supported options.
-  """
-  @spec print_metadata(map, keyword) :: :ok
-  def print_metadata(metadata, options \\ []) when is_map(metadata) do
-    options = Keyword.merge(default_options(), options)
-    print_each_metadata(metadata, options) && IO.write("\n")
-  end
-
-  @metadata_filter [:deprecated, :since]
-
-  defp print_each_metadata(metadata, options) do
-    Enum.reduce(metadata, false, fn
-      {key, value}, _printed when is_binary(value) and key in @metadata_filter ->
-        label = metadata_label(key, options)
-        indent = String.duplicate(" ", length_without_escape(label, 0) + 1)
-        write_with_wrap([label | String.split(value, @spaces)], options[:width], indent, true)
-
-      _metadata, printed ->
-        printed
-    end)
-  end
-
-  defp metadata_label(key, options) do
-    if options[:enabled] do
-      "#{color(:doc_metadata, options)}#{key}:#{IO.ANSI.reset()}"
-    else
-      "#{key}:"
-    end
+    newline_after_block
  end

  @doc """
  Prints the documentation body.

  In addition to the printing string, takes a set of options
-  defined in `default_options/0`.
+  defined in `default_options/1`.
  """
-  @spec print(String.t(), keyword) :: :ok
  def print(doc, options \\ []) do
-    options = Keyword.merge(default_options(), options)
-
+    options = Keyword.merge(default_options, options)
    doc
    |> String.split(["\r\n", "\n"], trim: false)
-    |> Enum.map(&String.trim_trailing/1)
+    |> Enum.map(&String.rstrip/1)
    |> process([], "", options)
  end

@@ -108,28 +66,22 @@ defmodule IO.ANSI.Docs do
    write_text(text, indent, options)
  end

-  defp process(["# " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
+  defp process(["# " <> heading | rest], text, indent, options) do
+    write_text(text, indent, options)
+    write_h1(String.strip(heading), options)
+    process(rest, [], "", options)
  end

-  defp process(["## " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
+  defp process(["## " <> heading | rest], text, indent, options) do
+    write_text(text, indent, options)
+    write_h2(String.strip(heading), options)
+    process(rest, [], "", options)
  end

-  defp process(["### " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
-  end
-
-  defp process(["#### " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
-  end
-
-  defp process(["##### " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
-  end
-
-  defp process(["###### " <> _ = heading | rest], text, indent, options) do
-    write_heading(heading, rest, text, indent, options)
+  defp process(["### " <> heading | rest], text, indent, options) do
+    write_text(text, indent, options)
+    write_h3(String.strip(heading), indent, options)
+    process(rest, [], "", options)
  end

  defp process(["" | rest], text, indent, options) do
@@ -150,18 +102,15 @@ defmodule IO.ANSI.Docs do
    process_fenced_code_block(rest, text, indent, options, _delimiter = "~~~")
  end

-  defp process(all = [line | rest], text, indent, options) do
+  defp process(all=[line | rest], text, indent, options) do
    {stripped, count} = strip_spaces(line, 0, :infinity)
-
    cond do
      link_label?(stripped, count) ->
        write_text([line], indent, options, true)
        process(rest, text, indent, options)
-
      table_line?(stripped) and rest != [] and table_line?(hd(rest)) ->
        write_text(text, indent, options)
        process_table(all, indent, options)
-
      true ->
        process_rest(stripped, rest, count, text, indent, options)
    end
@@ -169,11 +118,19 @@ defmodule IO.ANSI.Docs do

  ## Headings

-  defp write_heading(heading, rest, text, indent, options) do
-    write_text(text, indent, options)
+  defp write_h1(heading, options) do
+    write_h2(String.upcase(heading), options)
+  end
+
+  defp write_h2(heading, options) do
    write(:doc_headings, heading, options)
-    newline_after_block()
-    process(rest, [], "", options)
+    newline_after_block
+  end
+
+  defp write_h3(heading, indent, options) do
+    IO.write(indent)
+    write(:doc_headings, heading, options)
+    newline_after_block
  end

  ## Lists
@@ -183,15 +140,12 @@ defmodule IO.ANSI.Docs do
      <<bullet, ?\s, item::binary>> when bullet in @bullets ->
        write_text(text, indent, options)
        process_list("• ", item, rest, count, indent, options)
-
      <<d1, ?., ?\s, item::binary>> when d1 in ?0..?9 ->
        write_text(text, indent, options)
        process_list(<<d1, ?., ?\s>>, item, rest, count, indent, options)
-
      <<d1, d2, ?., ?\s, item::binary>> when d1 in ?0..?9 and d2 in ?0..?9 ->
        write_text(text, indent, options)
        process_list(<<d1, d2, ?., ?\s>>, item, rest, count, indent, options)
-
      _ ->
        process(rest, [stripped | text], indent, options)
    end
@@ -199,7 +153,7 @@ defmodule IO.ANSI.Docs do

  defp process_list(entry, line, rest, count, indent, options) do
    # The first list always win some extra padding
-    entry = if indent == "", do: "  " <> entry, else: entry
+    if indent == "", do: entry = "  " <> entry
    new_indent = indent <> String.duplicate(" ", String.length(entry))

    {contents, rest, done} = process_list_next(rest, count, byte_size(new_indent), [])
@@ -211,7 +165,6 @@ defmodule IO.ANSI.Docs do

  defp process_list_next([line | rest], count, max, acc) do
    {stripped, next_count} = strip_spaces(line, 0, max)
-
    case process_list_next_kind(stripped, rest, count, next_count) do
      :next -> process_list_next(rest, count, max, [stripped | acc])
      :done -> {Enum.reverse(acc), [line | rest], true}
@@ -227,20 +180,14 @@ defmodule IO.ANSI.Docs do
    case {stripped, rest} do
      {<<bullet, ?\s, _::binary>>, _} when bullet in @bullets and next_count <= count ->
        :list
-
      {<<d1, ?., ?\s, _::binary>>, _} when d1 in ?0..?9 and next_count <= count ->
        :list
-
-      {<<d1, d2, ?., ?\s, _::binary>>, _}
-      when d1 in ?0..?9 and d2 in ?0..?9 and next_count <= count ->
+      {<<d1, d2, ?., ?\s, _::binary>>, _} when d1 in ?0..?9 and d2 in ?0..?9 and next_count <= count ->
        :list
-
      {"", [" " <> _ | _]} ->
        :next
-
      {"", _} ->
        :done
-
      _ ->
        :next
    end
@@ -250,7 +197,7 @@ defmodule IO.ANSI.Docs do

  defp write_text(text, indent, options) do
    case Enum.reverse(text) do
-      [:no_wrap | rest] -> write_text(rest, indent, options, true)
+      [:no_wrap|rest] -> write_text(rest, indent, options, true)
      rest -> write_text(rest, indent, options, false)
    end
  end
@@ -264,7 +211,7 @@ defmodule IO.ANSI.Docs do
    |> Enum.join(" ")
    |> handle_links
    |> handle_inline(options)
-    |> String.split(@spaces)
+    |> String.split(~r{\s})
    |> write_with_wrap(options[:width] - byte_size(indent), indent, no_wrap)

    unless no_wrap, do: newline_after_block()
@@ -282,7 +229,7 @@ defmodule IO.ANSI.Docs do
  end

  defp process_code(["    " <> line | rest], code, indent, options) do
-    process_code(rest, [line | code], indent, options)
+    process_code(rest, [line|code], indent, options)
  end

  defp process_code(rest, code, indent, options) do
@@ -303,13 +250,13 @@ defmodule IO.ANSI.Docs do
    if line === delimiter do
      process_code(rest, code, indent, options)
    else
-      process_fenced_code(rest, [line | code], indent, options, delimiter)
+      process_fenced_code(rest, [line|code], indent, options, delimiter)
    end
  end

  defp write_code(code, indent, options) do
-    write(:doc_code, "#{indent}    #{Enum.join(Enum.reverse(code), "\n#{indent}    ")}", options)
-    newline_after_block()
+    write(:doc_code, "#{indent}┃ #{Enum.join(Enum.reverse(code), "\n#{indent}┃ ")}", options)
+    newline_after_block
  end

  ## Tables
@@ -317,44 +264,38 @@ defmodule IO.ANSI.Docs do
  defp process_table(lines, indent, options) do
    {table, rest} = Enum.split_while(lines, &table_line?/1)
    table_lines(table, options)
-    newline_after_block()
+    newline_after_block
    process(rest, [], indent, options)
  end

  defp table_lines(lines, options) do
    lines = Enum.map(lines, &split_into_columns(&1, options))
-    count = Enum.map(lines, &length/1) |> Enum.max()
+    count = Enum.map(lines, &length/1) |> Enum.max
    lines = Enum.map(lines, &pad_to_number_of_columns(&1, count))

-    widths =
-      for line <- lines do
-        if table_header?(line) do
-          for _ <- line, do: 0
-        else
-          for {_col, length} <- line, do: length
-        end
-      end
+    widths = for line <- lines, do:
+              (for {_col, length} <- line, do: length)
+
+    col_widths = Enum.reduce(widths,
+                             List.duplicate(0, count),
+                             &max_column_widths/2)

-    col_widths = Enum.reduce(widths, List.duplicate(0, count), &max_column_widths/2)
    render_table(lines, col_widths, options)
  end

  defp split_into_columns(line, options) do
    line
-    |> String.trim("|")
-    |> String.trim()
-    |> String.split(" | ")
+    |> String.strip(?|)
+    |> String.strip()
+    |> String.split(~r/\s\|\s/)
    |> Enum.map(&render_column(&1, options))
  end

  defp render_column(col, options) do
-    col =
-      col
-      |> String.replace("\\\|", "|")
-      |> String.trim()
-      |> handle_links
-      |> handle_inline(options)
-
+    col = col
+          |> String.replace(~r/\\ \|/x, "|")
+          |> handle_links
+          |> handle_inline(options)
    {col, length_without_escape(col, 0)}
  end

@@ -367,10 +308,7 @@ defmodule IO.ANSI.Docs do
  # If second line is heading separator, use the heading style on the first
  defp render_table([first, second | rest], widths, options) do
    combined = Enum.zip(first, widths)
-
    if table_header?(second) do
-      alignments = Enum.map(second, &column_alignment/1)
-      options = Keyword.put_new(options, :alignments, alignments)
      draw_table_row(combined, options, :heading)
      render_table(rest, widths, options)
    else
@@ -385,65 +323,31 @@ defmodule IO.ANSI.Docs do
    render_table(rest, widths, options)
  end

-  defp render_table([], _, _), do: nil
+  defp render_table([], _, _),
+    do: nil

-  defp column_alignment({line, _}) do
-    cond do
-      String.starts_with?(line, ":") and String.ends_with?(line, ":") -> :center
-      String.ends_with?(line, ":") -> :right
-      true -> :left
-    end
-  end
-
-  defp table_header?(line) do
-    Enum.all?(line, fn {col, _} -> table_header_column?(col) end)
-  end
-
-  defp table_header_column?(":" <> rest), do: table_header_contents?(rest)
-  defp table_header_column?(col), do: table_header_contents?(col)
-
-  defp table_header_contents?("-" <> rest), do: table_header_contents?(rest)
-  defp table_header_contents?(":"), do: true
-  defp table_header_contents?(""), do: true
-  defp table_header_contents?(_), do: false
+  defp table_header?(row), do:
+    Enum.all?(row, fn {col, _} -> col =~ ~r/^:?-+:?$/ end)

  defp draw_table_row(cols_and_widths, options, heading \\ false) do
-    default_alignments = List.duplicate(:left, length(cols_and_widths))
-    alignments = Keyword.get(options, :alignments, default_alignments)
-
    columns =
-      cols_and_widths
-      |> Enum.zip(alignments)
-      |> Enum.map_join(" | ", &generate_table_cell/1)
+      Enum.map_join(cols_and_widths, " | ", fn {{col, length}, width} ->
+        col <> String.duplicate(" ", width - length)
+      end)

    if heading do
      write(:doc_table_heading, columns, options)
    else
-      IO.puts(columns)
+      IO.puts columns
    end
  end

-  defp generate_table_cell({{{col, length}, width}, :center}) do
-    ansi_diff = byte_size(col) - length
-    width = width + ansi_diff
-
-    col
-    |> String.pad_leading(div(width, 2) - div(length, 2) + length)
-    |> String.pad_trailing(width + 1 - rem(width, 2))
-  end
-
-  defp generate_table_cell({{{col, length}, width}, :right}) do
-    ansi_diff = byte_size(col) - length
-    String.pad_leading(col, width + ansi_diff)
-  end
-
-  defp generate_table_cell({{{col, length}, width}, :left}) do
-    ansi_diff = byte_size(col) - length
-    String.pad_trailing(col, width + ansi_diff)
-  end
-
  defp table_line?(line) do
-    line =~ " | "
+    Regex.match?(~r'''
+      ( ^ \s{0,3} \| (?: [^|]+ \|)+ \s* $ )
+    |
+      (\s \| \s)
+    '''x, line)
  end

  ## Helpers
@@ -456,11 +360,13 @@ defmodule IO.ANSI.Docs do
  defp link_label?(""), do: false
  defp link_label?(<<_>> <> rest), do: link_label?(rest)

-  defp strip_spaces(" " <> line, acc, max) when acc < max, do: strip_spaces(line, acc + 1, max)
-  defp strip_spaces(rest, acc, _max), do: {rest, acc}
+  defp strip_spaces(" " <> line, acc, max) when acc < max,
+    do: strip_spaces(line, acc + 1, max)
+  defp strip_spaces(rest, acc, _max),
+    do: {rest, acc}

  defp write(style, string, options) do
-    IO.puts([color(style, options), string, IO.ANSI.reset()])
+    IO.puts [color(style, options), string, IO.ANSI.reset]
  end

  defp write_with_wrap([], _available, _indent, _first) do
@@ -469,17 +375,17 @@ defmodule IO.ANSI.Docs do

  defp write_with_wrap(words, available, indent, first) do
    {words, rest} = take_words(words, available, [])
-    IO.puts(if(first, do: "", else: indent) <> Enum.join(words, " "))
+    IO.puts (if first, do: "", else: indent) <> Enum.join(words, " ")
    write_with_wrap(rest, available, indent, false)
  end

-  defp take_words([word | words], available, acc) do
+  defp take_words([word|words], available, acc) do
    available = available - length_without_escape(word, 0)

    cond do
      # It fits, take one for space and continue decreasing
      available > 0 ->
-        take_words(words, available - 1, [word | acc])
+        take_words(words, available - 1, [word|acc])

      # No space but we got no words
      acc == [] ->
@@ -487,7 +393,7 @@ defmodule IO.ANSI.Docs do

      # Otherwise
      true ->
-        {Enum.reverse(acc), [word | words]}
+        {Enum.reverse(acc), [word|words]}
    end
  end

@@ -517,17 +423,14 @@ defmodule IO.ANSI.Docs do
  end

  defp escape_underlines_in_link(text) do
-    ~r{https?\S*}
-    |> Regex.recompile!()
-    |> Regex.replace(text, &String.replace(&1, "_", "\\_"))
+    Regex.replace(~r{https?\S*}, text, &String.replace(&1, "_", "\\_"))
  end

  defp remove_square_brackets_in_link(text) do
-    ~r{\[(.*?)\]\((.*?)\)}
-    |> Regex.recompile!()
-    |> Regex.replace(text, "\\1 (\\2)")
+    Regex.replace(~r{\[(.*?)\]\((.*?)\)}, text, "\\1 (\\2)")
  end

+
  # We have four entries: **, *, _ and `.
  #
  # The first three behave the same while the last one is simpler
@@ -543,8 +446,7 @@ defmodule IO.ANSI.Docs do

  # Characters that can mark the beginning or the end of a word.
  # Only support the most common ones at this moment.
-  @delimiters [?\s, ?', ?", ?!, ?@, ?#, ?$, ?%, ?^, ?&] ++
-                [?-, ?+, ?(, ?), ?[, ?], ?{, ?}, ?<, ?>, ?.]
+  @delimiters [?\s, ?', ?", ?!, ?@, ?#, ?$, ?%, ?^, ?&, ?-, ?+, ?(, ?), ?[, ?], ?{, ?}, ?<, ?>, ?.]

  # Inline start

@@ -563,90 +465,88 @@ defmodule IO.ANSI.Docs do
  # Inline delimiters

  defp handle_inline(<<delimiter, ?*, ?*, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and delimiter in @delimiters do
-    handle_inline(rest, ?d, ["**"], [delimiter, Enum.reverse(buffer) | acc], options)
+      when rest != "" and delimiter in @delimiters do
+    handle_inline(rest, ?d, ["**"], [delimiter, Enum.reverse(buffer)|acc], options)
  end

  defp handle_inline(<<delimiter, mark, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and delimiter in @delimiters and mark in @single do
-    handle_inline(rest, mark, [<<mark>>], [delimiter, Enum.reverse(buffer) | acc], options)
+      when rest != "" and delimiter in @delimiters and mark in @single do
+    handle_inline(rest, mark, [<<mark>>], [delimiter, Enum.reverse(buffer)|acc], options)
  end

  defp handle_inline(<<?`, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" do
-    handle_inline(rest, ?`, ["`"], [Enum.reverse(buffer) | acc], options)
+      when rest != "" do
+    handle_inline(rest, ?`, ["`"], [Enum.reverse(buffer)|acc], options)
  end

  # Clauses for handling escape

  defp handle_inline(<<?\\, ?\\, ?*, ?*, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" do
-    handle_inline(rest, ?d, ["**"], [?\\, Enum.reverse(buffer) | acc], options)
+      when rest != "" do
+    handle_inline(rest, ?d, ["**"], [?\\, Enum.reverse(buffer)|acc], options)
  end

  defp handle_inline(<<?\\, ?\\, mark, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and mark in @single do
-    handle_inline(rest, mark, [<<mark>>], [?\\, Enum.reverse(buffer) | acc], options)
+      when rest != "" and mark in @single do
+    handle_inline(rest, mark, [<<mark>>], [?\\, Enum.reverse(buffer)|acc], options)
  end

  defp handle_inline(<<?\\, ?\\, rest::binary>>, limit, buffer, acc, options) do
-    handle_inline(rest, limit, [?\\ | buffer], acc, options)
+    handle_inline(rest, limit, [?\\|buffer], acc, options)
  end

  # An escape is not valid inside `
  defp handle_inline(<<?\\, mark, rest::binary>>, limit, buffer, acc, options)
-       when not (mark == limit and mark == ?`) do
-    handle_inline(rest, limit, [mark | buffer], acc, options)
+      when not(mark == limit and mark == ?`) do
+    handle_inline(rest, limit, [mark|buffer], acc, options)
  end

  # Inline end

  defp handle_inline(<<?*, ?*, delimiter, rest::binary>>, ?d, buffer, acc, options)
-       when delimiter in @delimiters do
-    inline_buffer = inline_buffer(buffer, options)
-    handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer | acc], options)
+      when delimiter in @delimiters do
+    handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer(buffer, options)|acc], options)
  end

  defp handle_inline(<<mark, delimiter, rest::binary>>, mark, buffer, acc, options)
-       when delimiter in @delimiters and mark in @single do
-    inline_buffer = inline_buffer(buffer, options)
-    handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer | acc], options)
+      when delimiter in @delimiters and mark in @single do
+    handle_inline(<<delimiter, rest::binary>>, nil, [], [inline_buffer(buffer, options)|acc], options)
  end

  defp handle_inline(<<?*, ?*, rest::binary>>, ?d, buffer, acc, options)
-       when rest == "" do
-    handle_inline(<<>>, nil, [], [inline_buffer(buffer, options) | acc], options)
+      when rest == "" do
+    handle_inline(<<>>, nil, [], [inline_buffer(buffer, options)|acc], options)
  end

  defp handle_inline(<<mark, rest::binary>>, mark, buffer, acc, options)
-       when rest == "" and mark in @single do
-    handle_inline(<<>>, nil, [], [inline_buffer(buffer, options) | acc], options)
+      when rest == "" and mark in @single do
+    handle_inline(<<>>, nil, [], [inline_buffer(buffer, options)|acc], options)
  end

  defp handle_inline(<<?`, rest::binary>>, ?`, buffer, acc, options) do
-    handle_inline(rest, nil, [], [inline_buffer(buffer, options) | acc], options)
+    handle_inline(rest, nil, [], [inline_buffer(buffer, options)|acc], options)
  end

  # Catch all

  defp handle_inline(<<char, rest::binary>>, mark, buffer, acc, options) do
-    handle_inline(rest, mark, [char | buffer], acc, options)
+    handle_inline(rest, mark, [char|buffer], acc, options)
  end

  defp handle_inline(<<>>, _mark, buffer, acc, _options) do
-    IO.iodata_to_binary(Enum.reverse([Enum.reverse(buffer) | acc]))
+    IO.iodata_to_binary Enum.reverse([Enum.reverse(buffer)|acc])
  end

  defp inline_buffer(buffer, options) do
-    [h | t] = Enum.reverse([IO.ANSI.reset() | buffer])
-    [color_for(h, options) | t]
+    [h|t] = Enum.reverse([IO.ANSI.reset|buffer])
+    [color_for(h, options)|t]
  end

  defp color_for(mark, colors) do
    case mark do
-      "`" -> color(:doc_inline_code, colors)
-      "_" -> color(:doc_underline, colors)
-      "*" -> color(:doc_bold, colors)
+      "`"  -> color(:doc_inline_code, colors)
+      "_"  -> color(:doc_underline, colors)
+      "*"  -> color(:doc_bold, colors)
      "**" -> color(:doc_bold, colors)
    end
  end
@@ -656,5 +556,5 @@ defmodule IO.ANSI.Docs do
    IO.ANSI.format_fragment(color, colors[:enabled])
  end

-  defp newline_after_block, do: IO.puts(IO.ANSI.reset())
+  defp newline_after_block, do: IO.puts(IO.ANSI.reset)
 end
@@ -1,9 +1,8 @@
 defmodule IO.StreamError do
  defexception [:reason, :message]

-  @impl true
  def exception(opts) do
-    reason = opts[:reason]
+    reason    = opts[:reason]
    formatted = IO.iodata_to_binary(:file.format_error(reason))
    %IO.StreamError{message: "error during streaming: #{formatted}", reason: reason}
  end
@@ -17,10 +16,7 @@ defmodule IO.Stream do

    * `device`        - the IO device
    * `raw`           - a boolean indicating if bin functions should be used
-    * `line_or_bytes` - if reading should read lines or a given number of bytes
-
-  It is worth noting that an IO stream has side effects and every time you go
-  over the stream you may get different results.
+    * `line_or_bytes` - if reading should read lines or a given amount of bytes

  """

@@ -42,12 +38,10 @@ defmodule IO.Stream do
      fn
        :ok, {:cont, x} ->
          case raw do
-            true -> IO.binwrite(device, x)
+            true  -> IO.binwrite(device, x)
            false -> IO.write(device, x)
          end
-
-        :ok, _ ->
-          stream
+        :ok, _ -> stream
      end
    end
  end
@@ -56,11 +50,10 @@ defmodule IO.Stream do
    def reduce(%{device: device, raw: raw, line_or_bytes: line_or_bytes}, acc, fun) do
      next_fun =
        case raw do
-          true -> &IO.each_binstream(&1, line_or_bytes)
+          true  -> &IO.each_binstream(&1, line_or_bytes)
          false -> &IO.each_stream(&1, line_or_bytes)
        end
-
-      Stream.resource(fn -> device end, next_fun, & &1).(acc, fun)
+      Stream.resource(fn -> device end, next_fun, &(&1)).(acc, fun)
    end

    def count(_stream) do
@@ -70,9 +63,5 @@ defmodule IO.Stream do
    def member?(_stream, _term) do
      {:error, __MODULE__}
    end
-
-    def slice(_stream) do
-      {:error, __MODULE__}
-    end
  end
 end
@@ -1,17 +1,9 @@
 defmodule Kernel.CLI do
  @moduledoc false

-  @blank_config %{
-    commands: [],
-    output: ".",
-    compile: [],
-    halt: true,
-    compiler_options: [],
-    errors: [],
-    pa: [],
-    pz: [],
-    verbose_compile: false
-  }
+  @blank_config %{commands: [], output: ".", compile: [],
+                  halt: true, compiler_options: [], errors: [],
+                  pa: [], pz: [], verbose_compile: false}

  @doc """
  This is the API invoked by Elixir boot process.
@@ -22,16 +14,14 @@ defmodule Kernel.CLI do
    {config, argv} = parse_argv(argv)
    System.argv(argv)

-    fun = fn _ ->
+    run fn _ ->
      errors = process_commands(config)

      if errors != [] do
        Enum.each(errors, &IO.puts(:stderr, &1))
        System.halt(1)
      end
-    end
-
-    run(fun, config.halt)
+    end, config.halt
  end

  @doc """
@@ -44,7 +34,6 @@ defmodule Kernel.CLI do
  """
  def run(fun, halt \\ true) do
    {ok_or_shutdown, status} = exec_fun(fun, {:ok, 0})
-
    if ok_or_shutdown == :shutdown or halt do
      {_, status} = at_exit({ok_or_shutdown, status})

@@ -66,28 +55,10 @@ defmodule Kernel.CLI do
  @doc false
  def process_commands(config) do
    results = Enum.map(Enum.reverse(config.commands), &process_command(&1, config))
-    errors = for {:error, msg} <- results, do: msg
+    errors  = for {:error, msg} <- results, do: msg
    Enum.reverse(config.errors, errors)
  end

-  @doc false
-  def format_error(kind, reason, stacktrace) do
-    {blamed, stacktrace} = Exception.blame(kind, reason, stacktrace)
-
-    iodata =
-      case blamed do
-        %FunctionClauseError{} ->
-          formatted = Exception.format_banner(kind, reason, stacktrace)
-          padded_blame = pad(FunctionClauseError.blame(blamed, &inspect/1, &blame_match/2))
-          [formatted, padded_blame]
-
-        _ ->
-          Exception.format_banner(kind, blamed, stacktrace)
-      end
-
-    [iodata, ?\n, Exception.format_stacktrace(prune_stacktrace(stacktrace))]
-  end
-
  ## Helpers

  defp at_exit(res) do
@@ -105,23 +76,22 @@ defmodule Kernel.CLI do
          fun.(elem(res, 1))
        catch
          :exit, {:shutdown, int} when is_integer(int) ->
-            send(parent, {self(), {:shutdown, int}})
+            send parent, {self, {:shutdown, int}}
            exit({:shutdown, int})
-
          :exit, reason
-          when reason == :normal
-          when reason == :shutdown
-          when tuple_size(reason) == 2 and elem(reason, 0) == :shutdown ->
-            send(parent, {self(), {:shutdown, 0}})
+              when reason == :normal
+              when reason == :shutdown
+              when tuple_size(reason) == 2 and elem(reason, 0) == :shutdown ->
+            send parent, {self, {:shutdown, 0}}
            exit(reason)
-
          kind, reason ->
-            print_error(kind, reason, __STACKTRACE__)
-            send(parent, {self(), {:shutdown, 1}})
-            exit(to_exit(kind, reason, __STACKTRACE__))
+            stack = System.stacktrace
+            print_error(kind, reason, stack)
+            send parent, {self, {:shutdown, 1}}
+            exit(to_exit(kind, reason, stack))
        else
          _ ->
-            send(parent, {self(), res})
+            send parent, {self, res}
        end
      end)

@@ -129,7 +99,6 @@ defmodule Kernel.CLI do
      {^pid, res} ->
        :erlang.demonitor(ref, [:flush])
        res
-
      {:DOWN, ^ref, _, _, other} ->
        print_error({:EXIT, pid}, other, [])
        {:shutdown, 1}
@@ -142,53 +111,32 @@ defmodule Kernel.CLI do

  defp shared_option?(list, config, callback) do
    case parse_shared(list, config) do
-      {[h | hs], _} when h == hd(list) ->
+      {[h|hs], _} when h == hd(list) ->
        new_config = %{config | errors: ["#{h} : Unknown option" | config.errors]}
        callback.(hs, new_config)
-
      {new_list, new_config} ->
        callback.(new_list, new_config)
    end
  end

-  ## Error handling
-
-  defp print_error(kind, reason, stacktrace) do
-    IO.write(:stderr, format_error(kind, reason, stacktrace))
+  defp print_error(kind, reason, trace) do
+    IO.puts :stderr, Exception.format(kind, reason, prune_stacktrace(trace))
  end

-  defp blame_match(%{match?: true, node: node}, _), do: blame_ansi(:normal, "+", node)
-  defp blame_match(%{match?: false, node: node}, _), do: blame_ansi(:red, "-", node)
-  defp blame_match(_, string), do: string
+  @elixir_internals [:elixir, :elixir_exp, :elixir_compiler, :elixir_module, :elixir_clauses,
+                     :elixir_translator, :elixir_expand, :elixir_lexical, :elixir_exp_clauses,
+                     :elixir_def]

-  defp blame_ansi(color, no_ansi, node) do
-    if IO.ANSI.enabled?() do
-      [color | Macro.to_string(node)]
-      |> IO.ANSI.format(true)
-      |> IO.iodata_to_binary()
-    else
-      no_ansi <> Macro.to_string(node) <> no_ansi
-    end
-  end
-
-  defp pad(string) do
-    "    " <> String.replace(string, "\n", "\n    ")
-  end
-
-  @elixir_internals [:elixir, :elixir_aliases, :elixir_expand, :elixir_compiler, :elixir_module] ++
-                      [:elixir_clauses, :elixir_lexical, :elixir_def, :elixir_map] ++
-                      [:elixir_erl, :elixir_erl_clauses, :elixir_erl_pass, Kernel.ErrorHandler]
-
-  defp prune_stacktrace([{mod, _, _, _} | t]) when mod in @elixir_internals do
+  defp prune_stacktrace([{mod, _, _, _}|t]) when mod in @elixir_internals do
    prune_stacktrace(t)
  end

-  defp prune_stacktrace([{__MODULE__, :wrapper, 1, _} | _]) do
+  defp prune_stacktrace([{__MODULE__, :wrapper, 1, _}|_]) do
    []
  end

-  defp prune_stacktrace([h | t]) do
-    [h | prune_stacktrace(t)]
+  defp prune_stacktrace([h|t]) do
+    [h|prune_stacktrace(t)]
  end

  defp prune_stacktrace([]) do
@@ -197,60 +145,60 @@ defmodule Kernel.CLI do

  # Parse shared options

-  defp parse_shared([opt | _t], _config) when opt in ["-v", "--version"] do
-    if function_exported?(IEx, :started?, 0) and IEx.started?() do
-      IO.puts("IEx " <> System.build_info()[:build])
+  defp parse_shared([opt|_t], _config) when opt in ["-v", "--version"] do
+    if function_exported?(IEx, :started?, 0) and IEx.started? do
+      IO.puts "IEx #{System.version}"
    else
-      IO.puts(:erlang.system_info(:system_version))
-      IO.puts("Elixir " <> System.build_info()[:build])
+      IO.puts :erlang.system_info(:system_version)
+      {:ok, v} = Version.parse(System.version)
+
+      case v.pre do
+        [] -> IO.puts "Elixir #{System.version}"
+        _  -> IO.puts "Elixir #{System.version} (#{System.build_info().revision})"
+      end
    end

-    System.halt(0)
+    System.halt 0
  end

-  defp parse_shared(["-pa", h | t], config) do
+  defp parse_shared(["-pa", h|t], config) do
    paths = expand_code_path(h)
    Enum.each(paths, &:code.add_patha/1)
-    parse_shared(t, %{config | pa: config.pa ++ paths})
+    parse_shared t, %{config | pa: config.pa ++ paths}
  end

-  defp parse_shared(["-pz", h | t], config) do
+  defp parse_shared(["-pz", h|t], config) do
    paths = expand_code_path(h)
    Enum.each(paths, &:code.add_pathz/1)
-    parse_shared(t, %{config | pz: config.pz ++ paths})
+    parse_shared t, %{config | pz: config.pz ++ paths}
  end

-  defp parse_shared(["--app", h | t], config) do
-    parse_shared(t, %{config | commands: [{:app, h} | config.commands]})
+  defp parse_shared(["--app", h|t], config) do
+    parse_shared t, %{config | commands: [{:app, h} | config.commands]}
  end

-  defp parse_shared(["--no-halt" | t], config) do
-    parse_shared(t, %{config | halt: false})
+  defp parse_shared(["--no-halt"|t], config) do
+    parse_shared t, %{config | halt: false}
  end

-  defp parse_shared(["-e", h | t], config) do
-    parse_shared(t, %{config | commands: [{:eval, h} | config.commands]})
+  defp parse_shared(["-e", h|t], config) do
+    parse_shared t, %{config | commands: [{:eval, h} | config.commands]}
  end

-  defp parse_shared(["-r", h | t], config) do
-    parse_shared(t, %{config | commands: [{:require, h} | config.commands]})
+  defp parse_shared(["-r", h|t], config) do
+    parse_shared t, %{config | commands: [{:require, h} | config.commands]}
  end

-  defp parse_shared(["-pr", h | t], config) do
-    parse_shared(t, %{config | commands: [{:parallel_require, h} | config.commands]})
+  defp parse_shared(["-pr", h|t], config) do
+    parse_shared t, %{config | commands: [{:parallel_require, h} | config.commands]}
  end

-  @erl_arg_options ["--erl", "--sname", "--name", "--cookie"] ++
-                     ["--logger-otp-reports", "--logger-sasl-reports"]
-
-  @erl_boolean_options ["--detached", "--hidden", "--werl"]
-
-  defp parse_shared([erl, _ | t], config) when erl in @erl_arg_options do
-    parse_shared(t, config)
+  defp parse_shared([erl, _|t], config) when erl in ["--erl", "--sname", "--name", "--cookie"] do
+    parse_shared t, config
  end

-  defp parse_shared([erl | t], config) when erl in @erl_boolean_options do
-    parse_shared(t, config)
+  defp parse_shared([erl|t], config) when erl in ["--detached", "--hidden", "--werl"] do
+    parse_shared t, config
  end

  defp parse_shared(list, config) do
@@ -259,36 +207,34 @@ defmodule Kernel.CLI do

  defp expand_code_path(path) do
    path = Path.expand(path)
-
    case Path.wildcard(path) do
-      [] -> [to_charlist(path)]
-      list -> Enum.map(list, &to_charlist/1)
+      []   -> [to_char_list(path)]
+      list -> Enum.map(list, &to_char_list/1)
    end
  end

  # Process init options

-  defp parse_argv(["--" | t], config) do
+  defp parse_argv(["--"|t], config) do
    {config, t}
  end

-  defp parse_argv(["+elixirc" | t], config) do
-    parse_compiler(t, config)
+  defp parse_argv(["+elixirc"|t], config) do
+    parse_compiler t, config
  end

-  defp parse_argv(["+iex" | t], config) do
-    parse_iex(t, config)
+  defp parse_argv(["+iex"|t], config) do
+    parse_iex t, config
  end

-  defp parse_argv(["-S", h | t], config) do
+  defp parse_argv(["-S", h|t], config) do
    {%{config | commands: [{:script, h} | config.commands]}, t}
  end

-  defp parse_argv([h | t] = list, config) do
+  defp parse_argv([h|t] = list, config) do
    case h do
      "-" <> _ ->
-        shared_option?(list, config, &parse_argv(&1, &2))
-
+        shared_option? list, config, &parse_argv(&1, &2)
      _ ->
        if Keyword.has_key?(config.commands, :eval) do
          {config, list}
@@ -304,76 +250,74 @@ defmodule Kernel.CLI do

  # Parse compiler options

-  defp parse_compiler(["--" | t], config) do
+  defp parse_compiler(["--"|t], config) do
    {config, t}
  end

-  defp parse_compiler(["-o", h | t], config) do
-    parse_compiler(t, %{config | output: h})
+  defp parse_compiler(["-o", h|t], config) do
+    parse_compiler t, %{config | output: h}
  end

-  defp parse_compiler(["--no-docs" | t], config) do
-    parse_compiler(t, %{config | compiler_options: [{:docs, false} | config.compiler_options]})
+  defp parse_compiler(["--no-docs"|t], config) do
+    parse_compiler t, %{config | compiler_options: [{:docs, false} | config.compiler_options]}
  end

-  defp parse_compiler(["--no-debug-info" | t], config) do
-    compiler_options = [{:debug_info, false} | config.compiler_options]
-    parse_compiler(t, %{config | compiler_options: compiler_options})
+  defp parse_compiler(["--no-debug-info"|t], config) do
+    parse_compiler t, %{config | compiler_options: [{:debug_info, false} | config.compiler_options]}
  end

-  defp parse_compiler(["--ignore-module-conflict" | t], config) do
-    compiler_options = [{:ignore_module_conflict, true} | config.compiler_options]
-    parse_compiler(t, %{config | compiler_options: compiler_options})
+  defp parse_compiler(["--ignore-module-conflict"|t], config) do
+    parse_compiler t, %{config | compiler_options: [{:ignore_module_conflict, true} | config.compiler_options]}
  end

-  defp parse_compiler(["--warnings-as-errors" | t], config) do
-    compiler_options = [{:warnings_as_errors, true} | config.compiler_options]
-    parse_compiler(t, %{config | compiler_options: compiler_options})
+  defp parse_compiler(["--warnings-as-errors"|t], config) do
+    parse_compiler t, %{config | compiler_options: [{:warnings_as_errors, true} | config.compiler_options]}
  end

-  defp parse_compiler(["--verbose" | t], config) do
-    parse_compiler(t, %{config | verbose_compile: true})
+  defp parse_compiler(["--verbose"|t], config) do
+    parse_compiler t, %{config | verbose_compile: true}
  end

-  defp parse_compiler([h | t] = list, config) do
+  defp parse_compiler([h|t] = list, config) do
    case h do
      "-" <> _ ->
-        shared_option?(list, config, &parse_compiler(&1, &2))
-
+        shared_option? list, config, &parse_compiler(&1, &2)
      _ ->
        pattern = if File.dir?(h), do: "#{h}/**/*.ex", else: h
-        parse_compiler(t, %{config | compile: [pattern | config.compile]})
+        parse_compiler t, %{config | compile: [pattern | config.compile]}
    end
  end

  defp parse_compiler([], config) do
-    {%{config | commands: [{:compile, config.compile} | config.commands]}, []}
+    {%{config | commands: [{:compile, config.compile}|config.commands]}, []}
  end

-  # Parse IEx options
+  # Parse iex options

-  defp parse_iex(["--" | t], config) do
+  defp parse_iex(["--"|t], config) do
    {config, t}
  end

  # This clause is here so that Kernel.CLI does not
  # error out with "unknown option"
-  defp parse_iex(["--dot-iex", _ | t], config) do
-    parse_iex(t, config)
+  defp parse_iex(["--dot-iex", _|t], config) do
+    parse_iex t, config
  end

-  defp parse_iex([opt, _ | t], config) when opt in ["--remsh"] do
-    parse_iex(t, config)
+  defp parse_iex([opt, _|t], config) when opt in ["--remsh"] do
+    parse_iex t, config
  end

-  defp parse_iex(["-S", h | t], config) do
+  defp parse_iex(["-S", h|t], config) do
    {%{config | commands: [{:script, h} | config.commands]}, t}
  end

-  defp parse_iex([h | t] = list, config) do
+  defp parse_iex([h|t] = list, config) do
    case h do
-      "-" <> _ -> shared_option?(list, config, &parse_iex(&1, &2))
-      _ -> {%{config | commands: [{:file, h} | config.commands]}, t}
+      "-" <> _ ->
+        shared_option? list, config, &parse_iex(&1, &2)
+      _ ->
+        {%{config | commands: [{:file, h} | config.commands]}, t}
    end
  end

@@ -384,23 +328,22 @@ defmodule Kernel.CLI do
  # Process commands

  defp process_command({:cookie, h}, _config) do
-    if Node.alive?() do
-      wrapper(fn -> Node.set_cookie(String.to_atom(h)) end)
+    if Node.alive? do
+      wrapper fn -> Node.set_cookie(String.to_atom(h)) end
    else
      {:error, "--cookie : Cannot set cookie if the node is not alive (set --name or --sname)"}
    end
  end

  defp process_command({:eval, expr}, _config) when is_binary(expr) do
-    wrapper(fn -> Code.eval_string(expr, []) end)
+    wrapper fn -> Code.eval_string(expr, []) end
  end

  defp process_command({:app, app}, _config) when is_binary(app) do
    case Application.ensure_all_started(String.to_atom(app)) do
      {:error, {app, reason}} ->
-        msg = "--app : Could not start application #{app}: " <> Application.format_error(reason)
-        {:error, msg}
-
+        {:error, "--app : Could not start application #{app}: " <>
+          Application.format_error(reason)}
      {:ok, _} ->
        :ok
    end
@@ -408,7 +351,7 @@ defmodule Kernel.CLI do

  defp process_command({:script, file}, _config) when is_binary(file) do
    if exec = find_elixir_executable(file) do
-      wrapper(fn -> Code.require_file(exec) end)
+      wrapper fn -> Code.require_file(exec) end
    else
      {:error, "-S : Could not find executable #{file}"}
    end
@@ -416,7 +359,7 @@ defmodule Kernel.CLI do

  defp process_command({:file, file}, _config) when is_binary(file) do
    if File.regular?(file) do
-      wrapper(fn -> Code.require_file(file) end)
+      wrapper fn -> Code.require_file(file) end
    else
      {:error, "No file named #{file}"}
    end
@@ -426,7 +369,7 @@ defmodule Kernel.CLI do
    files = filter_patterns(pattern)

    if files != [] do
-      wrapper(fn -> Enum.map(files, &Code.require_file(&1)) end)
+      wrapper fn -> Enum.map files, &Code.require_file(&1) end
    else
      {:error, "-r : No files matched pattern #{pattern}"}
    end
@@ -436,12 +379,7 @@ defmodule Kernel.CLI do
    files = filter_patterns(pattern)

    if files != [] do
-      wrapper(fn ->
-        case Kernel.ParallelCompiler.require(files) do
-          {:ok, _, _} -> :ok
-          {:error, _, _} -> exit({:shutdown, 1})
-        end
-      end)
+      wrapper fn -> Kernel.ParallelRequire.files(files) end
    else
      {:error, "-pr : No files matched pattern #{pattern}"}
    end
@@ -454,24 +392,12 @@ defmodule Kernel.CLI do
    case filter_multiple_patterns(patterns) do
      {:ok, []} ->
        {:error, "No files matched provided patterns"}
-
      {:ok, files} ->
-        wrapper(fn ->
+        wrapper fn ->
          Code.compiler_options(config.compiler_options)
-
-          opts =
-            if config.verbose_compile do
-              [each_long_compilation: &IO.puts("Compiling #{&1} (it's taking more than 15s)")]
-            else
-              []
-            end
-
-          case Kernel.ParallelCompiler.compile_to_path(files, config.output, opts) do
-            {:ok, _, _} -> :ok
-            {:error, _, _} -> exit({:shutdown, 1})
-          end
-        end)
-
+          Kernel.ParallelCompiler.files_to_path(files, config.output,
+            each_file: fn file -> if config.verbose_compile do IO.puts "Compiled #{file}" end end)
+        end
      {:missing, missing} ->
        {:error, "No files matched pattern(s) #{Enum.join(missing, ",")}"}
    end
@@ -479,23 +405,31 @@ defmodule Kernel.CLI do

  defp filter_patterns(pattern) do
    pattern
-    |> Path.wildcard()
-    |> :lists.usort()
+    |> Path.wildcard
+    |> :lists.usort
    |> Enum.filter(&File.regular?/1)
  end

  defp filter_multiple_patterns(patterns) do
-    {files, missing} =
-      Enum.reduce(patterns, {[], []}, fn pattern, {files, missing} ->
-        case filter_patterns(pattern) do
-          [] -> {files, [pattern | missing]}
-          match -> {match ++ files, missing}
-        end
-      end)
+    matched_files = Enum.map patterns, fn(pattern) ->
+      case filter_patterns(pattern) do
+        []    -> {:missing, pattern}
+        files -> {:ok, files}
+      end
+    end

-    case missing do
-      [] -> {:ok, :lists.usort(files)}
-      _ -> {:missing, :lists.usort(missing)}
+    files = Enum.filter_map matched_files,
+       fn(match) -> elem(match, 0) == :ok end,
+       &elem(&1, 1)
+
+    missing_patterns = Enum.filter_map matched_files,
+       fn(match) -> elem(match, 0) == :missing end,
+       &elem(&1, 1)
+
+    if missing_patterns == [] do
+      {:ok, :lists.usort(Enum.concat(files))}
+    else
+      {:missing, :lists.usort(missing_patterns)}
    end
  end

@@ -513,7 +447,6 @@ defmodule Kernel.CLI do
        {:win32, _} ->
          base = Path.rootname(exec)
          if File.regular?(base), do: base, else: exec
-
        _ ->
          exec
      end
@@ -3,41 +3,38 @@
 defmodule Kernel.ErrorHandler do
  @moduledoc false

-  @spec undefined_function(module, atom, list) :: term
  def undefined_function(module, fun, args) do
-    ensure_loaded(module) or ensure_compiled(module, :module)
+    ensure_loaded(module)
    :error_handler.undefined_function(module, fun, args)
  end

-  @spec undefined_lambda(module, fun, list) :: term
  def undefined_lambda(module, fun, args) do
-    ensure_loaded(module) or ensure_compiled(module, :module)
+    ensure_loaded(module)
    :error_handler.undefined_lambda(module, fun, args)
  end

-  @spec ensure_loaded(module) :: boolean
-  def ensure_loaded(module) do
-    case :code.ensure_loaded(module) do
-      {:module, _} -> true
-      {:error, _} -> false
-    end
+  def release() do
+    # On release, no longer allow elixir_ensure_compiled
+    # directives and revert to the original error handler.
+    # Note we should not delete the elixir_compiler_pid though,
+    # as we still want to send notifications to the compiler.
+    :erlang.erase(:elixir_ensure_compiled)
+    :erlang.process_flag(:error_handler, :error_handler)
+    :ok
  end

-  @spec ensure_compiled(module, atom) :: boolean
-  # Never wait on nil because it should never be defined.
-  def ensure_compiled(nil, _kind) do
-    false
-  end
-
-  def ensure_compiled(module, kind) do
-    parent = :erlang.get(:elixir_compiler_pid)
-    ref = :erlang.make_ref()
-    send(parent, {:waiting, kind, self(), ref, module, :elixir_module.compiler_modules()})
-    :erlang.garbage_collect(self())
-
-    receive do
-      {^ref, :found} -> true
-      {^ref, :not_found} -> false
+  defp ensure_loaded(module) do
+    case Code.ensure_loaded(module) do
+      {:module, _} -> :ok
+      {:error, _} ->
+        parent = :erlang.get(:elixir_compiler_pid)
+        ref    = :erlang.make_ref
+        send parent, {:waiting, :module, self(), ref, module}
+        :erlang.garbage_collect(self)
+        receive do
+          {^ref, :ready}   -> :ok
+          {^ref, :release} -> release()
+        end
    end
  end
 end
@@ -1,41 +1,53 @@
-# This is an Elixir module responsible for tracking references
-# to modules, remote dispatches, and the usage of
-# aliases/imports/requires in the Elixir scope.
+# This is an Elixir module responsible for tracking
+# the usage of aliases, imports and requires in the Elixir scope.
+#
+# The implementation simply stores dispatch information in an
+# ETS table and then consults this table once compilation is done.
 #
 # Note that since this is required for bootstrap, we can't use
 # any of the `GenServer.Behaviour` conveniences.
 defmodule Kernel.LexicalTracker do
  @moduledoc false
-  @timeout 30000
+  @timeout 30_000
  @behaviour :gen_server

  @doc """
-  Returns all remotes referenced in this lexical scope.
+  Returns all remotes linked to in this lexical scope.
  """
-  def remote_references(arg) do
-    :gen_server.call(to_pid(arg), :remote_references, @timeout)
+  def remotes(arg) do
+    :gen_server.call(to_pid(arg), :ets, @timeout)
+    |> :ets.match({{:mode, :'$1'}, :'$2'})
+    |> partition([], [])
  end

+  defp partition([[remote, :compile]|t], compile, runtime),
+    do: partition(t, [remote|compile], runtime)
+  defp partition([[remote, :runtime]|t], compile, runtime),
+    do: partition(t, compile, [remote|runtime])
+  defp partition([], compile, runtime),
+    do: {compile, runtime}
+
  @doc """
-  Returns all remote dispatches in this lexical scope.
+  Gets the destination the lexical scope is meant to
+  compile to.
  """
-  def remote_dispatches(arg) do
-    :gen_server.call(to_pid(arg), :remote_dispatches, @timeout)
+  def dest(arg) do
+    :gen_server.call(to_pid(arg), :dest, @timeout)
  end

-  defp to_pid(pid) when is_pid(pid), do: pid
-
+  defp to_pid(pid) when is_pid(pid),  do: pid
  defp to_pid(mod) when is_atom(mod) do
-    {set, _} = :elixir_module.data_tables(mod)
-    :ets.lookup_element(set, {:elixir, :lexical_tracker}, 2)
+    table = :elixir_module.data_table(mod)
+    [{_, val}] = :ets.lookup(table, {:elixir, :lexical_tracker})
+    val
  end

  # Internal API

-  # Starts the tracker and returns its PID.
+  # Starts the tracker and returns its pid.
  @doc false
-  def start_link() do
-    :gen_server.start_link(__MODULE__, :ok, [])
+  def start_link(dest) do
+    :gen_server.start_link(__MODULE__, dest, [])
  end

  @doc false
@@ -44,62 +56,30 @@ defmodule Kernel.LexicalTracker do
  end

  @doc false
-  def add_import(pid, module, fas, line, warn) when is_atom(module) do
-    :gen_server.cast(pid, {:add_import, module, fas, line, warn})
+  def add_import(pid, module, line, warn) do
+    :gen_server.cast(pid, {:add_import, module, line, warn})
  end

  @doc false
-  def add_alias(pid, module, line, warn) when is_atom(module) do
+  def add_alias(pid, module, line, warn) do
    :gen_server.cast(pid, {:add_alias, module, line, warn})
  end

  @doc false
-  def remote_reference(pid, module, mode) when is_atom(module) do
-    :gen_server.cast(pid, {:remote_reference, module, mode})
+  def remote_dispatch(pid, module, mode) do
+    :gen_server.cast(pid, {:remote_dispatch, module, mode})
  end

  @doc false
-  def remote_dispatch(pid, module, fa, line, mode) when is_atom(module) do
-    :gen_server.cast(pid, {:remote_dispatch, module, fa, line, mode})
+  def import_dispatch(pid, module) do
+    :gen_server.cast(pid, {:import_dispatch, module})
  end

  @doc false
-  def remote_struct(pid, module, line) when is_atom(module) do
-    :gen_server.cast(pid, {:remote_struct, module, line})
-  end
-
-  @doc false
-  def import_dispatch(pid, module, fa, line, mode) when is_atom(module) do
-    :gen_server.cast(pid, {:import_dispatch, module, fa, line, mode})
-  end
-
-  @doc false
-  def alias_dispatch(pid, module) when is_atom(module) do
+  def alias_dispatch(pid, module) do
    :gen_server.cast(pid, {:alias_dispatch, module})
  end

-  @doc false
-  def set_file(pid, file) do
-    :gen_server.cast(pid, {:set_file, file})
-  end
-
-  @doc false
-  def reset_file(pid) do
-    :gen_server.cast(pid, :reset_file)
-  end
-
-  @doc false
-  def write_cache(pid, value) do
-    key = :erlang.unique_integer()
-    :gen_server.cast(pid, {:write_cache, key, value})
-    key
-  end
-
-  @doc false
-  def read_cache(pid, key) do
-    :gen_server.call(pid, {:read_cache, key}, @timeout)
-  end
-
  @doc false
  def collect_unused_imports(pid) do
    unused(pid, :import)
@@ -111,115 +91,61 @@ defmodule Kernel.LexicalTracker do
  end

  defp unused(pid, tag) do
-    :gen_server.call(pid, {:unused, tag}, @timeout)
+    :gen_server.call(pid, :ets, @timeout)
+    |> :ets.select([{{{tag, :"$1"}, :"$2"}, [is_integer: :"$2"], [{{:"$1", :"$2"}}]}])
+    |> Enum.sort
  end

  # Callbacks

-  def init(:ok) do
-    state = %{
-      directives: %{},
-      references: %{},
-      compile: %{},
-      runtime: %{},
-      structs: %{},
-      cache: %{},
-      file: nil
-    }
-
-    {:ok, state}
+  def init(dest) do
+    {:ok, {:ets.new(__MODULE__, [:protected]), dest}}
  end

  @doc false
-  def handle_call({:unused, tag}, _from, state) do
-    directives =
-      for {{^tag, module_or_mfa}, marker} <- state.directives, is_integer(marker) do
-        {module_or_mfa, marker}
-      end
-
-    {:reply, Enum.sort(directives), state}
+  def handle_call(:ets, _from, {d, dest}) do
+    {:reply, d, {d, dest}}
  end

-  def handle_call(:remote_references, _from, state) do
-    {compile, runtime} = partition(:maps.to_list(state.references), [], [])
-    {:reply, {compile, :maps.keys(state.structs), runtime}, state}
+  def handle_call(:dest, _from, {d, dest}) do
+    {:reply, dest, {d, dest}}
  end

-  def handle_call(:remote_dispatches, _from, state) do
-    {:reply, {state.compile, state.runtime}, state}
+  def handle_cast({:remote_dispatch, module, mode}, {d, dest}) do
+    add_compile(d, module, mode)
+    {:noreply, {d, dest}}
  end

-  def handle_call({:read_cache, key}, _from, %{cache: cache} = state) do
-    {:reply, :maps.get(key, cache), state}
+  def handle_cast({:import_dispatch, module}, {d, dest}) do
+    add_dispatch(d, module, :import)
+    # Always compile time because we depend
+    # on the module at compile time
+    add_compile(d, module, :compile)
+    {:noreply, {d, dest}}
  end

-  def handle_cast({:write_cache, key, value}, %{cache: cache} = state) do
-    {:noreply, %{state | cache: :maps.put(key, value, cache)}}
+  def handle_cast({:alias_dispatch, module}, {d, dest}) do
+    add_dispatch(d, module, :alias)
+    {:noreply, {d, dest}}
  end

-  def handle_cast({:remote_reference, module, mode}, state) do
-    {:noreply, %{state | references: add_reference(state.references, module, mode)}}
+  def handle_cast({:add_import, module, line, warn}, {d, dest}) do
+    add_directive(d, module, line, warn, :import)
+    {:noreply, {d, dest}}
  end

-  def handle_cast({:remote_struct, module, line}, state) do
-    state = add_remote_dispatch(state, module, {:__struct__, 1}, line, :compile)
-    structs = :maps.put(module, true, state.structs)
-    {:noreply, %{state | structs: structs}}
+  def handle_cast({:add_alias, module, line, warn}, {d, dest}) do
+    add_directive(d, module, line, warn, :alias)
+    {:noreply, {d, dest}}
  end

-  def handle_cast({:remote_dispatch, module, fa, line, mode}, state) do
-    references = add_reference(state.references, module, mode)
-    state = add_remote_dispatch(state, module, fa, line, mode)
-    {:noreply, %{state | references: references}}
-  end
-
-  def handle_cast({:import_dispatch, module, {function, arity} = fa, line, mode}, state) do
-    state =
-      state
-      |> add_import_dispatch(module, function, arity)
-      |> add_remote_dispatch(module, fa, line, mode)
-
-    {:noreply, state}
-  end
-
-  def handle_cast({:alias_dispatch, module}, state) do
-    {:noreply, %{state | directives: add_dispatch(state.directives, module, :alias)}}
-  end
-
-  def handle_cast({:set_file, file}, state) do
-    {:noreply, %{state | file: file}}
-  end
-
-  def handle_cast(:reset_file, state) do
-    {:noreply, %{state | file: nil}}
-  end
-
-  def handle_cast({:add_import, module, fas, line, warn}, state) do
-    directives =
-      state.directives
-      |> Enum.reject(&match?({{:import, {^module, _, _}}, _}, &1))
-      |> :maps.from_list()
-      |> add_directive(module, line, warn, :import)
-
-    directives =
-      Enum.reduce(fas, directives, fn {function, arity}, directives ->
-        add_directive(directives, {module, function, arity}, line, warn, :import)
-      end)
-
-    {:noreply, %{state | directives: directives}}
-  end
-
-  def handle_cast({:add_alias, module, line, warn}, state) do
-    {:noreply, %{state | directives: add_directive(state.directives, module, line, warn, :alias)}}
-  end
-
-  def handle_cast(:stop, state) do
-    {:stop, :normal, state}
+  def handle_cast(:stop, {d, dest}) do
+    {:stop, :normal, {d, dest}}
  end

  @doc false
-  def handle_info(_msg, state) do
-    {:noreply, state}
+  def handle_info(_msg, {d, dest}) do
+    {:noreply, {d, dest}}
  end

  @doc false
@@ -232,67 +158,21 @@ defmodule Kernel.LexicalTracker do
    {:ok, state}
  end

-  defp partition([{remote, :compile} | t], compile, runtime),
-    do: partition(t, [remote | compile], runtime)
-
-  defp partition([{remote, :runtime} | t], compile, runtime),
-    do: partition(t, compile, [remote | runtime])
-
-  defp partition([], compile, runtime), do: {compile, runtime}
-
  # Callbacks helpers

-  defp add_reference(references, module, :compile) when is_atom(module),
-    do: :maps.put(module, :compile, references)
-
-  defp add_reference(references, module, :runtime) when is_atom(module) do
-    case :maps.find(module, references) do
-      {:ok, _} -> references
-      :error -> :maps.put(module, :runtime, references)
-    end
-  end
-
-  defp add_remote_dispatch(state, module, fa, line, mode) when is_atom(module) do
-    location = location(state.file, line)
-
-    map_update(mode, %{module => %{fa => [location]}}, state, fn mode_dispatches ->
-      map_update(module, %{fa => [location]}, mode_dispatches, fn module_dispatches ->
-        map_update(fa, [location], module_dispatches, &[location | List.delete(&1, location)])
-      end)
-    end)
-  end
-
-  defp location(nil, line), do: line
-  defp location(file, line), do: {file, line}
-
-  defp add_import_dispatch(state, module, function, arity) do
-    directives =
-      add_dispatch(state.directives, module, :import)
-      |> add_dispatch({module, function, arity}, :import)
-
-    # Always compile time because we depend
-    # on the module at compile time
-    references = add_reference(state.references, module, :compile)
-
-    %{state | directives: directives, references: references}
-  end
-
-  # In the map we keep imports and aliases.
+  # In the table we keep imports and aliases.
+  # If the value is false, it was not imported/aliased
  # If the value is a line, it was imported/aliased and has a pending warning
  # If the value is true, it was imported/aliased and used
-  defp add_directive(directives, module_or_mfa, line, warn, tag) do
+  defp add_dispatch(d, module, tag) do
+    :ets.insert(d, {{tag, module}, true})
+  end
+
+  defp add_compile(d, module, :runtime), do: :ets.insert_new(d, {{:mode, module}, :runtime})
+  defp add_compile(d, module, :compile), do: :ets.insert(d, {{:mode, module}, :compile})
+
+  defp add_directive(d, module, line, warn, tag) do
    marker = if warn, do: line, else: true
-    :maps.put({tag, module_or_mfa}, marker, directives)
-  end
-
-  defp add_dispatch(directives, module_or_mfa, tag) do
-    :maps.put({tag, module_or_mfa}, true, directives)
-  end
-
-  defp map_update(key, initial, map, fun) do
-    case :maps.find(key, map) do
-      {:ok, val} -> :maps.put(key, fun.(val), map)
-      :error -> :maps.put(key, initial, map)
-    end
+    :ets.insert(d, {{tag, module}, marker})
  end
 end
@@ -1,40 +1,8 @@
 defmodule Kernel.ParallelCompiler do
  @moduledoc """
-  A module responsible for compiling and requiring files in parallel.
+  A module responsible for compiling files in parallel.
  """

-  @doc """
-  Starts a task for parallel compilation.
-
-  If you have a file that needs to compile other modules in parallel,
-  the spawned processes need to be aware of the compiler environment.
-  This function allows a developer to create a task that is aware of
-  those environments.
-
-  See `Task.async/1` for more information. The task spawned must be
-  always awaited on by calling `Task.await/1`
-  """
-  @doc since: "1.6.0"
-  def async(fun) when is_function(fun) do
-    if parent = :erlang.get(:elixir_compiler_pid) do
-      file = :erlang.get(:elixir_compiler_file)
-      dest = :erlang.get(:elixir_compiler_dest)
-      {:error_handler, error_handler} = :erlang.process_info(self(), :error_handler)
-
-      Task.async(fn ->
-        :erlang.put(:elixir_compiler_pid, parent)
-        :erlang.put(:elixir_compiler_file, file)
-        dest != :undefined and :erlang.put(:elixir_compiler_dest, dest)
-        :erlang.process_flag(:error_handler, error_handler)
-        fun.()
-      end)
-    else
-      raise ArgumentError,
-            "cannot spawn parallel compiler task because " <>
-              "the current file is not being compiled/required"
-    end
-  end
-
  @doc """
  Compiles the given files.

@@ -43,466 +11,254 @@ defmodule Kernel.ParallelCompiler do
  the current file stops being compiled until the dependency is
  resolved.

-  It returns `{:ok, modules, warnings}` or `{:error, errors, warnings}`.
+  If there is an error during compilation or if `warnings_as_errors`
+  is set to `true` and there is a warning, this function will fail
+  with an exception.

-  Both errors and warnings are a list of three element tuples containing
-  the file, line and the formatted error/warning.
-
-  ## Options
+  This function accepts the following options:

    * `:each_file` - for each file compiled, invokes the callback passing the
      file

-    * `:each_long_compilation` - for each file that takes more than a given
-      timeout (see the `:long_compilation_threshold` option) to compile, invoke
-      this callback passing the file as its argument
-
    * `:each_module` - for each module compiled, invokes the callback passing
      the file, module and the module bytecode

-    * `:each_cycle` - after the given files are compiled, invokes this function
-      that return a list with potentially more files to compile
-
-    * `:long_compilation_threshold` - the timeout (in seconds) after the
-      `:each_long_compilation` callback is invoked; defaults to `15`
-
-    * `:dest` - the destination directory for the BEAM files. When using `files/2`,
-      this information is only used to properly annotate the BEAM files before
+    * `:dest` - the destination directory for the beam files. When using `files/2`,
+      this information is only used to properly annotate the beam files before
      they are loaded into memory. If you want a file to actually be written to
-      `dest`, use `compile_to_path/3` instead.
+      `dest`, use `files_to_path/3` instead.

+  Returns the modules generated by each compiled file.
  """
-  @doc since: "1.6.0"
-  def compile(files, options \\ []) when is_list(options) do
-    spawn_workers(files, :compile, options)
-  end
+  def files(files, options \\ [])

-  @doc since: "1.6.0"
-  def compile_to_path(files, path, options \\ []) when is_binary(path) and is_list(options) do
-    spawn_workers(files, {:compile, path}, options)
+  def files(files, options) when is_list(options) do
+    spawn_compilers(files, nil, options)
  end

  @doc """
-  Requires the given files in parallel.
-
-  Opposite to compile, dependencies are not attempted to be
-  automatically solved between files.
-
-  It returns `{:ok, modules, warnings}` or `{:error, errors, warnings}`.
-
-  Both errors and warnings are a list of three element tuples containing
-  the file, line and the formatted error/warning.
-
-  ## Options
-
-    * `:each_file` - for each file compiled, invokes the callback passing the
-      file
-
-    * `:each_module` - for each module compiled, invokes the callback passing
-      the file, module and the module bytecode
-
+  Compiles the given files to the given path.
+  Read `files/2` for more information.
  """
-  @doc since: "1.6.0"
-  def require(files, options \\ []) when is_list(options) do
-    spawn_workers(files, :require, options)
+  def files_to_path(files, path, options \\ [])
+
+  def files_to_path(files, path, options) when is_binary(path) and is_list(options) do
+    spawn_compilers(files, path, options)
  end

-  # TODO: Deprecate on Elixir v1.8
-  @doc false
-  def files(files, options \\ []) when is_list(options) do
-    case spawn_workers(files, :compile, options) do
-      {:ok, modules, _} -> modules
-      {:error, _, _} -> exit({:shutdown, 1})
-    end
-  end
-
-  # TODO: Deprecate on Elixir v1.8
-  @doc false
-  def files_to_path(files, path, options \\ []) when is_binary(path) and is_list(options) do
-    case spawn_workers(files, {:compile, path}, options) do
-      {:ok, modules, _} -> modules
-      {:error, _, _} -> exit({:shutdown, 1})
-    end
-  end
-
-  defp spawn_workers(files, output, options) do
-    {:module, _} = :code.ensure_loaded(Kernel.ErrorHandler)
+  defp spawn_compilers(files, path, options) do
+    true = Code.ensure_loaded?(Kernel.ErrorHandler)
    compiler_pid = self()
    :elixir_code_server.cast({:reset_warnings, compiler_pid})
    schedulers = max(:erlang.system_info(:schedulers_online), 2)

-    result =
-      spawn_workers(files, [], [], [], [], %{
-        dest: Keyword.get(options, :dest),
-        each_cycle: Keyword.get(options, :each_cycle, fn -> [] end),
-        each_file: Keyword.get(options, :each_file, fn _file -> :ok end),
-        each_long_compilation: Keyword.get(options, :each_long_compilation, fn _file -> :ok end),
-        each_module: Keyword.get(options, :each_module, fn _file, _module, _binary -> :ok end),
-        output: output,
-        long_compilation_threshold: Keyword.get(options, :long_compilation_threshold, 15),
-        schedulers: schedulers
-      })
+    result = spawn_compilers(files, files, path, options, [], [], schedulers, [])

    # In case --warning-as-errors is enabled and there was a warning,
    # compilation status will be set to error.
-    compilation_status = :elixir_code_server.call({:compilation_status, compiler_pid})
-
-    case {result, compilation_status} do
-      {{:ok, _, warnings}, :error} ->
-        message = "Compilation failed due to warnings while using the --warnings-as-errors option"
-        IO.puts(:stderr, message)
-        {:error, warnings, []}
-
-      {{:error, errors, warnings}, :error} ->
-        {:error, errors ++ warnings, []}
-
-      _ ->
+    case :elixir_code_server.call({:compilation_status, compiler_pid}) do
+      :ok ->
        result
+      :error ->
+        IO.puts :stderr, "Compilation failed due to warnings while using the --warnings-as-errors option"
+        exit({:shutdown, 1})
    end
  end

-  # We already have n=schedulers currently running, don't spawn new ones
-  defp spawn_workers(files, waiting, queued, result, warnings, %{schedulers: schedulers} = state)
-       when length(queued) - length(waiting) >= schedulers do
-    wait_for_messages(files, waiting, queued, result, warnings, state)
+  # We already have 4 currently running, don't spawn new ones
+  defp spawn_compilers(entries, original, output, options, waiting, queued, schedulers, result) when
+      length(queued) - length(waiting) >= schedulers do
+    wait_for_messages(entries, original, output, options, waiting, queued, schedulers, result)
  end

  # Release waiting processes
-  defp spawn_workers([{ref, found} | t], waiting, queued, result, warnings, state) do
-    waiting =
-      case List.keytake(waiting, ref, 2) do
-        {{_kind, pid, ^ref, _on, _defining}, waiting} ->
-          send(pid, {ref, found})
-          waiting
-
-        nil ->
-          waiting
-      end
-
-    spawn_workers(t, waiting, queued, result, warnings, state)
+  defp spawn_compilers([h|t], original, output, options, waiting, queued, schedulers, result) when is_pid(h) do
+    {_kind, ^h, ref, _module} = List.keyfind(waiting, h, 1)
+    send h, {ref, :ready}
+    waiting = List.keydelete(waiting, h, 1)
+    spawn_compilers(t, original, output, options, waiting, queued, schedulers, result)
  end

-  defp spawn_workers([file | files], waiting, queued, result, warnings, state) do
-    %{output: output, long_compilation_threshold: threshold, dest: dest} = state
+  # Spawn a compiler for each file in the list until we reach the limit
+  defp spawn_compilers([h|t], original, output, options, waiting, queued, schedulers, result) do
    parent = self()

    {pid, ref} =
-      :erlang.spawn_monitor(fn ->
+      :erlang.spawn_monitor fn ->
+        # Notify Code.ensure_compiled/2 that we should
+        # attempt to compile the module by doing a dispatch.
+        :erlang.put(:elixir_ensure_compiled, true)
+
+        # Set the elixir_compiler_pid used by our custom Kernel.ErrorHandler.
        :erlang.put(:elixir_compiler_pid, parent)
-        :erlang.put(:elixir_compiler_file, file)
+        :erlang.process_flag(:error_handler, Kernel.ErrorHandler)

-        result =
-          try do
-            _ =
-              case output do
-                {:compile, path} ->
-                  :erlang.process_flag(:error_handler, Kernel.ErrorHandler)
-                  :erlang.put(:elixir_compiler_dest, path)
-                  :elixir_compiler.file_to_path(Path.expand(file), path)
-
-                :compile ->
-                  :erlang.process_flag(:error_handler, Kernel.ErrorHandler)
-                  :erlang.put(:elixir_compiler_dest, dest)
-                  Code.compile_file(file)
-
-                :require ->
-                  Code.require_file(file)
-              end
-
-            :ok
-          catch
-            kind, reason ->
-              {kind, reason, __STACKTRACE__}
+        exit(try do
+          _ = if output do
+            :elixir_compiler.file_to_path(h, output)
+          else
+            :elixir_compiler.file(h, Keyword.get(options, :dest))
          end
+          {:shutdown, h}
+        catch
+          kind, reason ->
+            {:failure, kind, reason, System.stacktrace}
+        end)
+      end

-        send(parent, {:file_done, self(), file, result})
-        exit(:shutdown)
-      end)
-
-    timer_ref = Process.send_after(self(), {:timed_out, pid}, threshold * 1000)
-    queued = [{pid, ref, file, timer_ref} | queued]
-    spawn_workers(files, waiting, queued, result, warnings, state)
+    spawn_compilers(t, original, output, options, waiting,
+                    [{pid, ref, h}|queued], schedulers, result)
  end

-  # No more files, nothing waiting, queue is empty, this cycle is done
-  defp spawn_workers([], [], [], result, warnings, state) do
-    case state.each_cycle.() do
-      [] ->
-        modules = for {:module, mod} <- result, do: mod
-        warnings = Enum.reverse(warnings)
-        {:ok, modules, warnings}
-
-      more ->
-        spawn_workers(more, [], [], result, warnings, state)
-    end
+  # No more files, nothing waiting, queue is empty, we are done
+  defp spawn_compilers([], _original, _output, _options, [], [], _schedulers, result) do
+    for {:module, mod} <- result, do: mod
  end

  # Queued x, waiting for x: POSSIBLE ERROR! Release processes so we get the failures
-
-  # Single entry, just release it.
-  defp spawn_workers([], [_] = waiting, [_] = queued, result, warnings, state) do
-    [{_, _, ref, _, _}] = waiting
-    spawn_workers([{ref, :not_found}], waiting, queued, result, warnings, state)
-  end
-
-  # Multiple entries, try to release modules.
-  defp spawn_workers([], waiting, queued, result, warnings, state)
-       when length(waiting) == length(queued) do
-    # The goal of this function is to find leaves in the dependency graph,
-    # i.e. to find code that depends on code that we know is not being defined.
-    # Note we only release modules because those can be rescued. A missing
-    # struct is a guaranteed compile error, so we never release it and treat
-    # it exclusively a missing entry/deadlock.
-    pending =
-      for {pid, _, _, _} <- queued,
-          entry = waiting_on_without_definition(waiting, pid),
-          {kind, _, ref, on, _} = entry,
-          kind == :module,
-          do: {on, {ref, :not_found}}
-
-    # Instead of releasing all files at once, we release them in groups
-    # based on the module they are waiting on. We pick the module being
-    # depended on with less edges, as it is the mostly likely source of
-    # error (for example, someone made a typo). This may not always be
-    # true though. For example, if there is a macro injecting code into
-    # multiple modules and such code becomes faulty, now multiple modules
-    # are waiting on the same module required by the faulty code. However,
-    # since we need to pick something to be first, the one with fewer edges
-    # sounds like a sane choice.
-    pending
-    |> Enum.group_by(&elem(&1, 0), &elem(&1, 1))
-    |> Enum.sort_by(&length(elem(&1, 1)))
-    |> case do
-      [{_on, refs} | _] ->
-        spawn_workers(refs, waiting, queued, result, warnings, state)
-
-      [] ->
-        errors = handle_deadlock(waiting, queued)
-        {:error, errors, warnings}
+  defp spawn_compilers([], original, output, options, waiting, queued, schedulers, result) when length(waiting) == length(queued) do
+    Enum.each queued, fn {child, _, _} ->
+      {_kind, ^child, ref, _module} = List.keyfind(waiting, child, 1)
+      send child, {ref, :release}
    end
+    wait_for_messages([], original, output, options, waiting, queued, schedulers, result)
  end

  # No more files, but queue and waiting are not full or do not match
-  defp spawn_workers([], waiting, queued, result, warnings, state) do
-    wait_for_messages([], waiting, queued, result, warnings, state)
-  end
-
-  defp waiting_on_without_definition(waiting, pid) do
-    {_, ^pid, _, on, _} = entry = List.keyfind(waiting, pid, 1)
-
-    if Enum.any?(waiting, fn {_, _, _, _, defining} -> on in defining end) do
-      nil
-    else
-      entry
-    end
+  defp spawn_compilers([], original, output, options, waiting, queued, schedulers, result) do
+    wait_for_messages([], original, output, options, waiting, queued, schedulers, result)
  end

  # Wait for messages from child processes
-  defp wait_for_messages(files, waiting, queued, result, warnings, state) do
-    %{output: output} = state
-
+  defp wait_for_messages(entries, original, output, options, waiting, queued, schedulers, result) do
    receive do
      {:struct_available, module} ->
-        available =
-          for {:struct, _, ref, waiting_module, _defining} <- waiting,
-              module == waiting_module,
-              do: {ref, :found}
+        available = for {:struct, pid, _, waiting_module} <- waiting,
+                        module == waiting_module,
+                        not pid in entries,
+                        do: pid

-        result = [{:struct, module} | result]
-        spawn_workers(available ++ files, waiting, queued, result, warnings, state)
+        spawn_compilers(available ++ entries, original, output, options,
+                        waiting, queued, schedulers, [{:struct, module}|result])

      {:module_available, child, ref, file, module, binary} ->
-        state.each_module.(file, module, binary)
-
-        # Release the module loader which is waiting for an ack
-        send(child, {ref, :ack})
-
-        available =
-          for {:module, _, ref, waiting_module, _defining} <- waiting,
-              module == waiting_module,
-              do: {ref, :found}
-
-        cancel_waiting_timer(queued, child)
-
-        result = [{:module, module} | result]
-        spawn_workers(available ++ files, waiting, queued, result, warnings, state)
-
-      # If we are simply requiring files, we do not add to waiting.
-      {:waiting, _kind, child, ref, _on, _defining} when output == :require ->
-        send(child, {ref, :not_found})
-        spawn_workers(files, waiting, queued, result, warnings, state)
-
-      {:waiting, kind, child, ref, on, defining} ->
-        # Oops, we already got it, do not put it on waiting.
-        # Alternatively, we're waiting on ourselves,
-        # send :found so that we can crash with a better error.
-        waiting =
-          if :lists.any(&match?({^kind, ^on}, &1), result) or on in defining do
-            send(child, {ref, :found})
-            waiting
-          else
-            [{kind, child, ref, on, defining} | waiting]
-          end
-
-        spawn_workers(files, waiting, queued, result, warnings, state)
-
-      {:timed_out, child} ->
-        case List.keyfind(queued, child, 0) do
-          {^child, _, file, _} ->
-            state.each_long_compilation.(file)
-
-          _ ->
-            :ok
+        if callback = Keyword.get(options, :each_module) do
+          callback.(file, module, binary)
        end

-        spawn_workers(files, waiting, queued, result, warnings, state)
+        # Release the module loader which is waiting for an ack
+        send child, {ref, :ack}

-      {:warning, file, line, message} ->
-        file = file && Path.absname(file)
-        message = :unicode.characters_to_binary(message)
-        warning = {file, line, message}
-        wait_for_messages(files, waiting, queued, result, [warning | warnings], state)
+        available = for {_kind, pid, _, waiting_module} <- waiting,
+                        module == waiting_module,
+                        not pid in entries,
+                        do: pid

-      {:file_done, child_pid, file, :ok} ->
-        discard_down(child_pid)
-        state.each_file.(file)
-        cancel_waiting_timer(queued, child_pid)
+        spawn_compilers(available ++ entries, original, output, options,
+                        waiting, queued, schedulers, [{:module, module}|result])
+
+      {:waiting, kind, child, ref, on} ->
+        defined = fn {k, m} -> on == m and k in [kind, :module] end
+
+        # Oops, we already got it, do not put it on waiting.
+        if :lists.any(defined, result) do
+          send child, {ref, :ready}
+        else
+          waiting = [{kind, child, ref, on}|waiting]
+        end
+
+        spawn_compilers(entries, original, output, options, waiting, queued, schedulers, result)
+
+      {:DOWN, _down_ref, :process, down_pid, {:shutdown, file}} ->
+        if callback = Keyword.get(options, :each_file) do
+          callback.(file)
+        end

        # Sometimes we may have spurious entries in the waiting
        # list because someone invoked try/rescue UndefinedFunctionError
-        new_files = List.delete(files, child_pid)
-        new_queued = List.keydelete(queued, child_pid, 0)
-        new_waiting = List.keydelete(waiting, child_pid, 1)
-        spawn_workers(new_files, new_waiting, new_queued, result, warnings, state)
+        new_entries = List.delete(entries, down_pid)
+        new_queued  = List.keydelete(queued, down_pid, 0)
+        new_waiting = List.keydelete(waiting, down_pid, 1)
+        spawn_compilers(new_entries, original, output, options, new_waiting, new_queued, schedulers, result)

-      {:file_done, child_pid, file, {kind, reason, stack}} ->
-        discard_down(child_pid)
-        print_error(file, kind, reason, stack)
-        cancel_waiting_timer(queued, child_pid)
-        terminate(queued)
-        {:error, [to_error(file, kind, reason, stack)], warnings}
-
-      {:DOWN, ref, :process, _pid, reason} ->
-        case handle_down(queued, ref, reason) do
-          :ok -> wait_for_messages(files, waiting, queued, result, warnings, state)
-          {:error, errors} -> {:error, errors, warnings}
-        end
+      {:DOWN, down_ref, :process, _down_pid, reason} ->
+        handle_failure(down_ref, reason, entries, waiting, queued)
+        wait_for_messages(entries, original, output, options, waiting, queued, schedulers, result)
    end
  end

-  defp discard_down(pid) do
-    receive do
-      {:DOWN, _, :process, ^pid, _} -> :ok
+  defp handle_failure(ref, reason, entries, waiting, queued) do
+    if file = find_failure(ref, queued) do
+      print_failure(file, reason)
+
+      if all_missing?(entries, waiting, queued) do
+        collect_failures(queued, length(queued) - 1)
+      end
+
+      Enum.each queued, fn {child, _, _} ->
+        Process.exit(child, :kill)
+      end
+
+      exit({:shutdown, 1})
    end
  end

-  defp handle_down(_queued, _ref, :normal) do
+  defp find_failure(ref, queued) do
+    case List.keyfind(queued, ref, 1) do
+      {_child, ^ref, file} -> file
+      _ -> nil
+    end
+  end
+
+  defp print_failure(_file, {:shutdown, _}) do
    :ok
  end

-  defp handle_down(queued, ref, reason) do
-    case List.keyfind(queued, ref, 1) do
-      {_child, ^ref, file, _timer_ref} ->
-        print_error(file, :exit, reason, [])
-        terminate(queued)
-        {:error, [to_error(file, :exit, reason, [])]}
-
-      _ ->
-        :ok
-    end
+  defp print_failure(file, {:failure, kind, reason, stacktrace}) do
+    IO.puts "\n== Compilation error on file #{Path.relative_to_cwd(file)} =="
+    IO.puts Exception.format(kind, reason, prune_stacktrace(stacktrace))
  end

-  defp handle_deadlock(waiting, queued) do
-    deadlock =
-      for {pid, _, file, _} <- queued do
-        {:current_stacktrace, stacktrace} = Process.info(pid, :current_stacktrace)
-        Process.exit(pid, :kill)
-
-        {kind, ^pid, _, on, _} = List.keyfind(waiting, pid, 1)
-        description = "deadlocked waiting on #{kind} #{inspect(on)}"
-        error = CompileError.exception(description: description, file: nil, line: nil)
-        print_error(file, :error, error, stacktrace)
-
-        {file, on, description}
-      end
-
-    IO.puts("""
-
-    Compilation failed because of a deadlock between files.
-    The following files depended on the following modules:
-    """)
-
-    max =
-      deadlock
-      |> Enum.map(&(&1 |> elem(0) |> String.length()))
-      |> Enum.max()
-
-    for {file, mod, _} <- deadlock do
-      IO.puts(["  ", String.pad_leading(file, max), " => " | inspect(mod)])
-    end
-
-    IO.puts(
-      "\nEnsure there are no compile-time dependencies between those files " <>
-        "and that the modules they reference exist and are correctly named\n"
-    )
-
-    for {file, _, description} <- deadlock, do: {Path.absname(file), nil, description}
+  defp print_failure(file, reason) do
+    IO.puts "\n== Compilation error on file #{Path.relative_to_cwd(file)} =="
+    IO.puts Exception.format(:exit, reason, [])
  end

-  defp terminate(queued) do
-    for {pid, _, _, _} <- queued do
-      Process.exit(pid, :kill)
-    end
+  @elixir_internals [:elixir, :elixir_exp, :elixir_compiler, :elixir_module, :elixir_clauses,
+                     :elixir_translator, :elixir_expand, :elixir_lexical, :elixir_exp_clauses,
+                     :elixir_def]
+
+  defp prune_stacktrace([{mod, _, _, _}|t]) when mod in @elixir_internals do
+    prune_stacktrace(t)
  end

-  defp print_error(file, kind, reason, stack) do
-    IO.write([
-      "\n== Compilation error in file #{Path.relative_to_cwd(file)} ==\n",
-      Kernel.CLI.format_error(kind, reason, stack)
-    ])
+  defp prune_stacktrace([h|t]) do
+    [h|prune_stacktrace(t)]
  end

-  defp cancel_waiting_timer(queued, child_pid) do
-    case List.keyfind(queued, child_pid, 0) do
-      {^child_pid, _ref, _file, timer_ref} ->
-        Process.cancel_timer(timer_ref)
-        # Let's flush the message in case it arrived before we canceled the
-        # timeout.
-        receive do
-          {:timed_out, ^child_pid} -> :ok
-        after
-          0 -> :ok
+  defp prune_stacktrace([]) do
+    []
+  end
+
+  defp all_missing?(entries, waiting, queued) do
+    entries == [] and waiting != [] and
+      length(waiting) == length(queued)
+  end
+
+  defp collect_failures(_queued, 0), do: :ok
+
+  defp collect_failures(queued, remaining) do
+    receive do
+      {:DOWN, down_ref, :process, _down_pid, reason} ->
+        if file = find_failure(down_ref, queued) do
+          print_failure(file, reason)
+          collect_failures(queued, remaining - 1)
+        else
+          collect_failures(queued, remaining)
        end
-
-      nil ->
-        :ok
+    after
+      # Give up if no failure appears in 5 seconds
+      5000 -> :ok
    end
  end
-
-  defp to_error(file, kind, reason, stack) do
-    line = get_line(file, reason, stack)
-    file = Path.absname(file)
-    message = :unicode.characters_to_binary(Kernel.CLI.format_error(kind, reason, stack))
-    {file, line, message}
-  end
-
-  defp get_line(_file, %{line: line}, _stack) when is_integer(line) and line > 0 do
-    line
-  end
-
-  defp get_line(file, :undef, [{_, _, _, []}, {_, _, _, info} | _]) do
-    if Keyword.get(info, :file) == to_charlist(Path.relative_to_cwd(file)) do
-      Keyword.get(info, :line)
-    end
-  end
-
-  defp get_line(file, _reason, [{_, _, _, info} | _]) do
-    if Keyword.get(info, :file) == to_charlist(Path.relative_to_cwd(file)) do
-      Keyword.get(info, :line)
-    end
-  end
-
-  defp get_line(_, _, _) do
-    nil
-  end
 end
@@ -1,17 +1,85 @@
 defmodule Kernel.ParallelRequire do
-  # TODO: Deprecate on Elixir v1.8
-  @moduledoc false
+  @moduledoc """
+  A module responsible for requiring files in parallel.
+  """

-  def files(files, callbacks \\ [])
+  @doc """
+  Requires the given files.

-  def files(files, callback) when is_function(callback, 1) do
-    files(files, each_file: callback)
+  A callback that is invoked every time a file is required
+  can be optionally given as argument.
+
+  Returns the modules generated by each required file.
+  """
+  def files(files, callback \\ fn x -> x end) do
+    compiler_pid = self()
+    :elixir_code_server.cast({:reset_warnings, compiler_pid})
+    schedulers = max(:erlang.system_info(:schedulers_online), 2)
+    result = spawn_requires(files, [], callback, schedulers, [])
+
+    # In case --warning-as-errors is enabled and there was a warning,
+    # compilation status will be set to error.
+    case :elixir_code_server.call({:compilation_status, compiler_pid}) do
+      :ok ->
+        result
+      :error ->
+        IO.puts :stderr, "Compilation failed due to warnings while using the --warnings-as-errors option"
+        exit({:shutdown, 1})
+    end
  end

-  def files(files, options) when is_list(options) do
-    case Kernel.ParallelCompiler.require(files, options) do
-      {:ok, modules, _} -> modules
-      {:error, _, _} -> exit({:shutdown, 1})
+  defp spawn_requires([], [], _callback, _schedulers, result), do: result
+
+  defp spawn_requires([], waiting, callback, schedulers, result) do
+    wait_for_messages([], waiting, callback, schedulers, result)
+  end
+
+  defp spawn_requires(files, waiting, callback, schedulers, result) when length(waiting) >= schedulers do
+    wait_for_messages(files, waiting, callback, schedulers, result)
+  end
+
+  defp spawn_requires([h|t], waiting, callback, schedulers, result) do
+    parent = self()
+    {pid, ref} = :erlang.spawn_monitor fn ->
+      :erlang.put(:elixir_compiler_pid, parent)
+
+      exit(try do
+        new = Code.require_file(h) || []
+        {:required, Enum.map(new, &elem(&1, 0)), h}
+      catch
+        kind, reason ->
+          {:failure, kind, reason, System.stacktrace}
+      end)
+    end
+
+    spawn_requires(t, [{pid, ref}|waiting], callback, schedulers, result)
+  end
+
+  defp wait_for_messages(files, waiting, callback, schedulers, result) do
+    receive do
+      {:DOWN, ref, :process, pid, status} ->
+        tuple = {pid, ref}
+        if tuple in waiting do
+          case status do
+            {:required, mods, file} ->
+              callback.(file)
+              result  = mods ++ result
+              waiting = List.delete(waiting, tuple)
+            {:failure, kind, reason, stacktrace} ->
+              :erlang.raise(kind, reason, stacktrace)
+            other ->
+              :erlang.raise(:exit, other, [])
+          end
+        end
+        spawn_requires(files, waiting, callback, schedulers, result)
+      {:module_available, child, ref, _, _, _} ->
+        send(child, {ref, :ack})
+        spawn_requires(files, waiting, callback, schedulers, result)
+      {:struct_available, _} ->
+        spawn_requires(files, waiting, callback, schedulers, result)
+      {:waiting, :struct, child, ref, _} ->
+        send(child, {ref, :release})
+        spawn_requires(files, waiting, callback, schedulers, result)
    end
  end
 end
@@ -3,30 +3,18 @@ import Kernel, except: [destructure: 2, defdelegate: 2, defstruct: 2]
 defmodule Kernel.Utils do
  @moduledoc false

-  @doc """
-  Callback for destructure.
-  """
-  def destructure(list, count)
-      when is_list(list) and is_integer(count) and count >= 0,
-      do: destructure_list(list, count)
-
-  def destructure(nil, count)
-      when is_integer(count) and count >= 0,
-      do: destructure_nil(count)
+  def destructure(list, count) when is_list(list), do: destructure_list(list, count)
+  def destructure(nil, count), do: destructure_nil(count)

  defp destructure_list(_, 0), do: []
  defp destructure_list([], count), do: destructure_nil(count)
-  defp destructure_list([h | t], count), do: [h | destructure_list(t, count - 1)]
+  defp destructure_list([h|t], count), do: [h|destructure_list(t, count - 1)]

  defp destructure_nil(0), do: []
-  defp destructure_nil(count), do: [nil | destructure_nil(count - 1)]
+  defp destructure_nil(count), do: [nil|destructure_nil(count - 1)]

-  @doc """
-  Callback for defdelegate.
-  """
-  def defdelegate(fun, opts) when is_list(opts) do
-    # TODO: Remove by 2.0
-    append_first? = Keyword.get(opts, :append_first, false)
+  def defdelegate(fun, opts, env) do
+    append_first = Keyword.get(opts, :append_first, false)

    {name, args} =
      case Macro.decompose_call(fun) do
@@ -34,46 +22,37 @@ defmodule Kernel.Utils do
        _ -> raise ArgumentError, "invalid syntax in defdelegate #{Macro.to_string(fun)}"
      end

-    as = Keyword.get(opts, :as, name)
-    as_args = build_as_args(args, append_first?)
+    :ok = check_defdelegate_args(args, env)

+    as_args =
+      case append_first and args != [] do
+        true  -> tl(args) ++ [hd(args)]
+        false -> args
+      end
+
+    as = Keyword.get(opts, :as, name)
    {name, args, as, as_args}
  end

-  defp build_as_args(args, append_first?) do
-    as_args = :lists.map(&build_as_arg/1, args)
-
-    case append_first? do
-      true -> tl(as_args) ++ [hd(as_args)]
-      false -> as_args
-    end
+  # TODO: Convert this to an error on 1.3
+  defp check_defdelegate_args([], _env),
+    do: :ok
+  defp check_defdelegate_args([{var, _, mod}|rest], env) when is_atom(var) and is_atom(mod),
+    do: check_defdelegate_args(rest, env)
+  defp check_defdelegate_args([code|_], env) do
+    :elixir_errors.warn(env.line, env.file,
+      "defdelegate/2 will only accept variable names in upcoming versions, " <>
+      "got: #{Macro.to_string(code)}")
  end

-  defp build_as_arg({:\\, _, [arg, _default_arg]}), do: validate_arg(arg)
-  defp build_as_arg(arg), do: validate_arg(arg)
-
-  defp validate_arg({name, _, mod} = arg) when is_atom(name) and is_atom(mod) do
-    arg
-  end
-
-  defp validate_arg(ast) do
-    raise ArgumentError,
-          "defdelegate/2 only accepts function parameters, got: #{Macro.to_string(ast)}"
-  end
-
-  @doc """
-  Callback for defstruct.
-  """
  def defstruct(module, fields) do
    case fields do
-      fs when is_list(fs) ->
-        :ok
-
+      fs when is_list(fs) -> :ok
      other ->
-        raise ArgumentError, "struct fields definition must be list, got: #{inspect(other)}"
+        raise ArgumentError, "struct fields definition must be list, got: #{inspect other}"
    end

-    mapper = fn
+    fields = :lists.map(fn
      {key, val} when is_atom(key) ->
        try do
          Macro.escape(val)
@@ -83,186 +62,12 @@ defmodule Kernel.Utils do
        else
          _ -> {key, val}
        end
-
      key when is_atom(key) ->
        {key, nil}
-
      other ->
-        raise ArgumentError, "struct field names must be atoms, got: #{inspect(other)}"
-    end
+        raise ArgumentError, "struct field names must be atoms, got: #{inspect other}"
+    end, fields)

-    fields = :lists.map(mapper, fields)
-    enforce_keys = List.wrap(Module.get_attribute(module, :enforce_keys))
-
-    foreach = fn
-      key when is_atom(key) ->
-        :ok
-
-      key ->
-        raise ArgumentError, "keys given to @enforce_keys must be atoms, got: #{inspect(key)}"
-    end
-
-    :lists.foreach(foreach, enforce_keys)
-
-    struct = :maps.put(:__struct__, module, :maps.from_list(fields))
-    {struct, enforce_keys, Module.get_attribute(module, :derive)}
-  end
-
-  @doc """
-  Announcing callback for defstruct.
-  """
-  def announce_struct(module) do
-    case :erlang.get(:elixir_compiler_pid) do
-      :undefined -> :ok
-      pid -> send(pid, {:struct_available, module})
-    end
-  end
-
-  @doc """
-  Callback for raise.
-  """
-  def raise(msg) when is_binary(msg) do
-    RuntimeError.exception(msg)
-  end
-
-  def raise(module) when is_atom(module) do
-    module.exception([])
-  end
-
-  def raise(%_{__exception__: true} = exception) do
-    exception
-  end
-
-  def raise(other) do
-    ArgumentError.exception(
-      "raise/1 and reraise/2 expect a module name, string or exception " <>
-        "as the first argument, got: #{inspect(other)}"
-    )
-  end
-
-  @doc """
-  Callback for defguard.
-
-  Rewrites an expression so it can be used both inside and outside a guard.
-
-  Take, for example, the expression:
-
-      is_integer(value) and rem(value, 2) == 0
-
-  If we wanted to create a macro, `is_even`, from this expression, that could be
-  used in guards, we'd have to take several things into account.
-
-  First, if this expression is being used inside a guard, `value` needs to be
-  unquoted each place it occurs, since it has not yet been at that point in our
-  macro.
-
-  Secondly, if the expression is being used outside of a guard, we want to unquote
-  `value`––but only once, and then re-use the unquoted form throughout the expression.
-
-  This helper does exactly that: takes the AST for an expression and a list of
-  variable references it should be aware of, and rewrites it into a new expression
-  that checks for its presence in a guard, then unquotes the variable references as
-  appropriate.
-
-  The resulting transformation looks something like this:
-
-      > expression = quote do: is_integer(value) and rem(value, 2) == 0
-      > variable_references = [value: Elixir]
-      > Kernel.Utils.defguard(expression, variable_references) |> Macro.to_string |> IO.puts
-
-      case Macro.Env.in_guard? __CALLER__ do
-        true -> quote do
-          is_integer(unquote(value)) and rem(unquote(value), 2) == 0
-        end
-        false -> quote do
-          value = unquote(value)
-          is_integer(value) and rem(value, 2) == 0
-        end
-      end
-
-  """
-  defmacro defguard(args, expr) do
-    defguard(args, expr, __CALLER__)
-  end
-
-  @spec defguard([Macro.t()], Macro.t(), Macro.Env.t()) :: Macro.t()
-  def defguard(args, expr, env) do
-    {^args, vars} = extract_refs_from_args(args)
-    env = :elixir_env.with_vars(%{env | context: :guard}, vars)
-    {expr, _scope} = :elixir_expand.expand(expr, env)
-
-    quote do
-      case Macro.Env.in_guard?(__CALLER__) do
-        true -> unquote(literal_quote(unquote_every_ref(expr, vars)))
-        false -> unquote(literal_quote(unquote_refs_once(expr, vars)))
-      end
-    end
-  end
-
-  defp extract_refs_from_args(args) do
-    Macro.postwalk(args, [], fn
-      {ref, meta, context} = var, acc when is_atom(ref) and is_atom(context) ->
-        {var, [{ref, var_context(meta, context)} | acc]}
-
-      node, acc ->
-        {node, acc}
-    end)
-  end
-
-  # Finds every reference to `refs` in `guard` and wraps them in an unquote.
-  defp unquote_every_ref(guard, refs) do
-    Macro.postwalk(guard, fn
-      {ref, meta, context} = var when is_atom(ref) and is_atom(context) ->
-        case {ref, var_context(meta, context)} in refs do
-          true -> literal_unquote(var)
-          false -> var
-        end
-
-      node ->
-        node
-    end)
-  end
-
-  # Prefaces `guard` with unquoted versions of `refs`.
-  defp unquote_refs_once(guard, refs) do
-    {_, used_refs} =
-      Macro.postwalk(guard, [], fn
-        {ref, meta, context} = var, acc when is_atom(ref) and is_atom(context) ->
-          pair = {ref, var_context(meta, context)}
-
-          case pair in refs and pair not in acc do
-            true -> {var, [pair | acc]}
-            false -> {var, acc}
-          end
-
-        node, acc ->
-          {node, acc}
-      end)
-
-    vars = for {ref, context} <- :lists.reverse(used_refs), do: context_to_var(ref, context)
-    exprs = for var <- vars, do: literal_unquote(var)
-
-    quote do
-      {unquote_splicing(vars)} = {unquote_splicing(exprs)}
-      unquote(guard)
-    end
-  end
-
-  defp literal_quote(ast) do
-    {:quote, [], [[do: ast]]}
-  end
-
-  defp literal_unquote(ast) do
-    {:unquote, [], List.wrap(ast)}
-  end
-
-  defp context_to_var(ref, ctx) when is_atom(ctx), do: {ref, [], ctx}
-  defp context_to_var(ref, ctx) when is_integer(ctx), do: {ref, [counter: ctx], nil}
-
-  defp var_context(meta, kind) do
-    case :lists.keyfind(:counter, 1, meta) do
-      {:counter, counter} -> counter
-      false -> kind
-    end
+    :maps.put(:__struct__, module, :maps.from_list(fields))
  end
 end
@@ -2,46 +2,12 @@ defmodule Keyword do
  @moduledoc """
  A set of functions for working with keywords.

-  A keyword is a list of two-element tuples where the first
+  A keyword is a list of 2-element tuples where the first
  element of the tuple is an atom and the second element
  can be any value.

-  For example, the following is a keyword list:
-
-      [{:exit_on_close, true}, {:active, :once}, {:packet_size, 1024}]
-
-  Elixir provides a special and more concise syntax for keyword lists
-  that looks like this:
-
-      [exit_on_close: true, active: :once, packet_size: 1024]
-
-  This is also the syntax that Elixir uses to inspect keyword lists:
-
-      iex> [{:active, :once}]
-      [active: :once]
-
-  The two syntaxes are completely equivalent. If the keyword has foreign
-  characters, such as spaces, you can wrap it in quotes:
-
-      iex> ["exit on close": true]
-      ["exit on close": true]
-
-  Wrapping a keyword in quotes does not make it a string. Keywords are
-  always atoms and quotes should only be used to handle foreign characters.
-  In fact, if you attempt use quotes when not necessary, Elixir will warn.
-
-  Note that when keyword lists are passed as the last argument to a function,
-  if the short-hand syntax is used then the square brackets around the keyword list
-  can be omitted as well. For example, the following:
-
-      String.split("1-0", "-", trim: true, parts: 2)
-
-  is equivalent to:
-
-      String.split("1-0", "-", [trim: true, parts: 2])
-
  A keyword may have duplicated keys so it is not strictly
-  a key-value store. However most of the functions in this module
+  a dictionary. However most of the functions in this module
  behave exactly as a dictionary so they work similarly to
  the functions you would find in the `Map` module.

@@ -49,10 +15,6 @@ defmodule Keyword do
  the given key, regardless if duplicated entries exist.
  Similarly, `Keyword.put/3` and `Keyword.delete/3` ensure all
  duplicated entries for a given key are removed when invoked.
-  Note that operations that require keys to be found in the keyword
-  list (like `Keyword.get/3`) need to traverse the list in order
-  to find keys, so these operations may be slower than their map
-  counterparts.

  A handful of functions exist to handle duplicated keys, in
  particular, `Enum.into/2` allows creating new keywords without
@@ -60,10 +22,10 @@ defmodule Keyword do
  a given key and `delete_first/2` deletes just one of the existing
  entries.

-  The functions in `Keyword` do not guarantee any property when
+  The functions in Keyword do not guarantee any property when
  it comes to ordering. However, since a keyword list is simply a
  list, all the operations defined in `Enum` and `List` can be
-  applied too, especially when ordering is required.
+  applied too, specially when ordering is required.
  """

  @compile :inline_list_funcs
@@ -97,7 +59,7 @@ defmodule Keyword do
  def keyword?(term)

  def keyword?([{key, _value} | rest]) when is_atom(key), do: keyword?(rest)
-  def keyword?([]), do: true
+  def keyword?([]),     do: true
  def keyword?(_other), do: false

  @doc """
@@ -109,7 +71,7 @@ defmodule Keyword do
      []

  """
-  @spec new :: []
+  @spec new :: t
  def new, do: []

  @doc """
@@ -128,7 +90,7 @@ defmodule Keyword do
      [a: 3]

  """
-  @spec new(Enum.t()) :: t
+  @spec new(Enum.t) :: t
  def new(pairs) do
    new(pairs, fn pair -> pair end)
  end
@@ -142,17 +104,16 @@ defmodule Keyword do

  ## Examples

-      iex> Keyword.new([:a, :b], fn x -> {x, x} end)
+      iex> Keyword.new([:a, :b], fn (x) -> {x, x} end)
      [a: :a, b: :b]

  """
-  @spec new(Enum.t(), (term -> {key, value})) :: t
+  @spec new(Enum.t, (term -> {key, value})) :: t
  def new(pairs, transform) do
    fun = fn el, acc ->
      {k, v} = transform.(el)
      put_new(acc, k, v)
    end
-
    :lists.foldl(fun, [], Enum.reverse(pairs))
  end

@@ -184,6 +145,7 @@ defmodule Keyword do
      3

  """
+  @spec get(t, key) :: value
  @spec get(t, key, value) :: value
  def get(keywords, key, default \\ nil) when is_list(keywords) and is_atom(key) do
    case :lists.keyfind(key, 1, keywords) do
@@ -229,14 +191,12 @@ defmodule Keyword do
  Gets the value from `key` and updates it, all in one pass.

  This `fun` argument receives the value of `key` (or `nil` if `key`
-  is not present) and must return a two-element tuple: the "get" value
-  (the retrieved value, which can be operated on before being returned)
-  and the new value to be stored under `key`. The `fun` may also
-  return `:pop`, implying the current value shall be removed from the
-  keyword list and returned.
+  is not present) and must return a two-elements tuple: the "get" value (the
+  retrieved value, which can be operated on before being returned) and the new
+  value to be stored under `key`.

-  The returned value is a tuple with the "get" value returned by
-  `fun` and a new keyword list with the updated value under `key`.
+  The returned value is a tuple with the "get" value returned by `fun` and a new
+  keyword list with the updated value under `key`.

  ## Examples

@@ -250,51 +210,30 @@ defmodule Keyword do
      ...> end)
      {nil, [b: "new value!", a: 1]}

-      iex> Keyword.get_and_update([a: 1], :a, fn _ -> :pop end)
-      {1, []}
-
-      iex> Keyword.get_and_update([a: 1], :b, fn _ -> :pop end)
-      {nil, [a: 1]}
-
  """
-  @spec get_and_update(t, key, (value -> {get, value} | :pop)) :: {get, t} when get: term
+  @spec get_and_update(t, key, (value -> {get, value})) :: {get, t} when get: term
  def get_and_update(keywords, key, fun)
-      when is_list(keywords) and is_atom(key),
-      do: get_and_update(keywords, [], key, fun)
+    when is_list(keywords) and is_atom(key),
+    do: get_and_update(keywords, [], key, fun)

-  defp get_and_update([{key, current} | t], acc, key, fun) do
-    case fun.(current) do
-      {get, value} ->
-        {get, :lists.reverse(acc, [{key, value} | t])}
-
-      :pop ->
-        {current, :lists.reverse(acc, t)}
-
-      other ->
-        raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
-    end
+  defp get_and_update([{key, value}|t], acc, key, fun) do
+    {get, new_value} = fun.(value)
+    {get, :lists.reverse(acc, [{key, new_value}|t])}
  end

-  defp get_and_update([{_, _} = h | t], acc, key, fun), do: get_and_update(t, [h | acc], key, fun)
+  defp get_and_update([h|t], acc, key, fun),
+    do: get_and_update(t, [h|acc], key, fun)

  defp get_and_update([], acc, key, fun) do
-    case fun.(nil) do
-      {get, update} ->
-        {get, [{key, update} | :lists.reverse(acc)]}
-
-      :pop ->
-        {nil, :lists.reverse(acc)}
-
-      other ->
-        raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
-    end
+    {get, update} = fun.(nil)
+    {get, [{key, update}|:lists.reverse(acc)]}
  end

  @doc """
  Gets the value from `key` and updates it. Raises if there is no `key`.

  This `fun` argument receives the value of `key` and must return a
-  two-element tuple: the "get" value (the retrieved value, which can be
+  two-elements tuple: the "get" value (the retrieved value, which can be
  operated on before being returned) and the new value to be stored under
  `key`.

@@ -303,7 +242,7 @@ defmodule Keyword do

  ## Examples

-      iex> Keyword.get_and_update!([a: 1], :a, fn current_value ->
+      iex> Keyword.get_and_update!([a: 1], :a, fn(current_value) ->
      ...>   {current_value, "new value!"}
      ...> end)
      {1, [a: "new value!"]}
@@ -313,32 +252,19 @@ defmodule Keyword do
      ...> end)
      ** (KeyError) key :b not found in: [a: 1]

-      iex> Keyword.get_and_update!([a: 1], :a, fn _ ->
-      ...>   :pop
-      ...> end)
-      {1, []}
-
  """
  @spec get_and_update!(t, key, (value -> {get, value})) :: {get, t} | no_return when get: term
  def get_and_update!(keywords, key, fun) do
    get_and_update!(keywords, key, fun, [])
  end

-  defp get_and_update!([{key, value} | keywords], key, fun, acc) do
-    case fun.(value) do
-      {get, value} ->
-        {get, :lists.reverse(acc, [{key, value} | delete(keywords, key)])}
-
-      :pop ->
-        {value, :lists.reverse(acc, keywords)}
-
-      other ->
-        raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
-    end
+  defp get_and_update!([{key, value}|keywords], key, fun, acc) do
+    {get, value} = fun.(value)
+    {get, :lists.reverse(acc, [{key, value}|delete(keywords, key)])}
  end

-  defp get_and_update!([{_, _} = e | keywords], key, fun, acc) do
-    get_and_update!(keywords, key, fun, [e | acc])
+  defp get_and_update!([{_, _} = e|keywords], key, fun, acc) do
+    get_and_update!(keywords, key, fun, [e|acc])
  end

  defp get_and_update!([], key, _fun, acc) when is_atom(key) do
@@ -403,10 +329,9 @@ defmodule Keyword do
  @spec get_values(t, key) :: [value]
  def get_values(keywords, key) when is_list(keywords) and is_atom(key) do
    fun = fn
-      {^key, val} -> {true, val}
+      {k, v} when k === key -> {true, v}
      {_, _} -> false
    end
-
    :lists.filtermap(fun, keywords)
  end

@@ -465,22 +390,7 @@ defmodule Keyword do
  """
  @spec delete(t, key, value) :: t
  def delete(keywords, key, value) when is_list(keywords) and is_atom(key) do
-    case :lists.keymember(key, 1, keywords) do
-      true -> delete_key_value(keywords, key, value)
-      _ -> keywords
-    end
-  end
-
-  defp delete_key_value([{key, value} | tail], key, value) do
-    delete_key_value(tail, key, value)
-  end
-
-  defp delete_key_value([{_, _} = pair | tail], key, value) do
-    [pair | delete_key_value(tail, key, value)]
-  end
-
-  defp delete_key_value([], _key, _value) do
-    []
+    :lists.filter(fn {k, v} -> k != key or v != value end, keywords)
  end

  @doc """
@@ -501,24 +411,8 @@ defmodule Keyword do

  """
  @spec delete(t, key) :: t
-  @compile {:inline, delete: 2}
  def delete(keywords, key) when is_list(keywords) and is_atom(key) do
-    case :lists.keymember(key, 1, keywords) do
-      true -> delete_key(keywords, key)
-      _ -> keywords
-    end
-  end
-
-  defp delete_key([{key, _} | tail], key) do
-    delete_key(tail, key)
-  end
-
-  defp delete_key([{_, _} = pair | tail], key) do
-    [pair | delete_key(tail, key)]
-  end
-
-  defp delete_key([], _key) do
-    []
+    :lists.filter(fn {k, _} -> k != key end, keywords)
  end

  @doc """
@@ -536,22 +430,7 @@ defmodule Keyword do
  """
  @spec delete_first(t, key) :: t
  def delete_first(keywords, key) when is_list(keywords) and is_atom(key) do
-    case :lists.keymember(key, 1, keywords) do
-      true -> delete_first_key(keywords, key)
-      _ -> keywords
-    end
-  end
-
-  defp delete_first_key([{key, _} | tail], key) do
-    tail
-  end
-
-  defp delete_first_key([{_, _} = pair | tail], key) do
-    [pair | delete_first_key(tail, key)]
-  end
-
-  defp delete_first_key([], _key) do
-    []
+    :lists.keydelete(key, 1, keywords)
  end

  @doc """
@@ -572,7 +451,7 @@ defmodule Keyword do
  """
  @spec put(t, key, value) :: t
  def put(keywords, key, value) when is_list(keywords) and is_atom(key) do
-    [{key, value} | delete(keywords, key)]
+    [{key, value}|delete(keywords, key)]
  end

  @doc """
@@ -600,7 +479,7 @@ defmodule Keyword do
      when is_list(keywords) and is_atom(key) and is_function(fun, 0) do
    case :lists.keyfind(key, 1, keywords) do
      {^key, _} -> keywords
-      false -> [{key, fun.()} | keywords]
+      false -> [{key, fun.()}|keywords]
    end
  end

@@ -620,40 +499,7 @@ defmodule Keyword do
  def put_new(keywords, key, value) when is_list(keywords) and is_atom(key) do
    case :lists.keyfind(key, 1, keywords) do
      {^key, _} -> keywords
-      false -> [{key, value} | keywords]
-    end
-  end
-
-  @doc false
-  @deprecated "Use Keyword.fetch/2 + Keyword.put/3 instead"
-  def replace(keywords, key, value) when is_list(keywords) and is_atom(key) do
-    case :lists.keyfind(key, 1, keywords) do
-      {^key, _} -> [{key, value} | delete(keywords, key)]
-      false -> keywords
-    end
-  end
-
-  @doc """
-  Alters the value stored under `key` to `value`, but only
-  if the entry `key` already exists in `keywords`.
-
-  If `key` is not present in `keywords`, a `KeyError` exception is raised.
-
-  ## Examples
-
-      iex> Keyword.replace!([a: 1, b: 2, a: 4], :a, 3)
-      [a: 3, b: 2]
-
-      iex> Keyword.replace!([a: 1], :b, 2)
-      ** (KeyError) key :b not found in: [a: 1]
-
-  """
-  @doc since: "1.5.0"
-  @spec replace!(t, key, value) :: t
-  def replace!(keywords, key, value) when is_list(keywords) and is_atom(key) do
-    case :lists.keyfind(key, 1, keywords) do
-      {^key, _} -> [{key, value} | delete(keywords, key)]
-      false -> raise KeyError, key: key, term: keywords
+      false -> [{key, value}|keywords]
    end
  end

@@ -694,32 +540,11 @@ defmodule Keyword do
      iex> Keyword.merge([a: 1, b: 2], [a: 3, d: 4, a: 5])
      [b: 2, a: 3, d: 4, a: 5]

-      iex> Keyword.merge([a: 1], [2, 3])
-      ** (ArgumentError) expected a keyword list as the second argument, got: [2, 3]
-
  """
  @spec merge(t, t) :: t
-  def merge(keywords1, keywords2)
-
-  def merge(keywords1, []), do: keywords1
-  def merge([], keywords2), do: keywords2
-
  def merge(keywords1, keywords2) when is_list(keywords1) and is_list(keywords2) do
-    if keyword?(keywords2) do
-      fun = fn
-        {key, _value} when is_atom(key) ->
-          not has_key?(keywords2, key)
-
-        _ ->
-          raise ArgumentError,
-            message: "expected a keyword list as the first argument, got: #{inspect(keywords1)}"
-      end
-
-      :lists.filter(fun, keywords1) ++ keywords2
-    else
-      raise ArgumentError,
-        message: "expected a keyword list as the second argument, got: #{inspect(keywords2)}"
-    end
+    fun = fn {k, _v} -> not has_key?(keywords2, k) end
+    :lists.filter(fun, keywords1) ++ keywords2
  end

  @doc """
@@ -750,44 +575,26 @@ defmodule Keyword do
      ...> end)
      [b: 2, a: 4, d: 4, a: 8]

-      iex> Keyword.merge([a: 1, b: 2], [:a, :b], fn :a, v1, v2 ->
-      ...>  v1 + v2
-      ...> end)
-      ** (ArgumentError) expected a keyword list as the second argument, got: [:a, :b]
-
  """
  @spec merge(t, t, (key, value, value -> value)) :: t
-  def merge(keywords1, keywords2, fun)
-      when is_list(keywords1) and is_list(keywords2) and is_function(fun, 3) do
-    if keyword?(keywords1) do
-      do_merge(keywords2, [], keywords1, keywords1, fun, keywords2)
-    else
-      raise ArgumentError,
-        message: "expected a keyword list as the first argument, got: #{inspect(keywords1)}"
-    end
+  def merge(keywords1, keywords2, fun) when is_list(keywords1) and is_list(keywords2) do
+    do_merge(keywords2, [], keywords1, keywords1, fun)
  end

-  defp do_merge([{key, value2} | tail], acc, rest, original, fun, keywords2) when is_atom(key) do
-    case :lists.keyfind(key, 1, original) do
-      {^key, value1} ->
-        acc = [{key, fun.(key, value1, value2)} | acc]
-        original = :lists.keydelete(key, 1, original)
-        do_merge(tail, acc, delete(rest, key), original, fun, keywords2)
-
+  defp do_merge([{k, v2}|t], acc, rest, original, fun) do
+    case :lists.keyfind(k, 1, original) do
+      {^k, v1} ->
+        do_merge(t, [{k, fun.(k, v1, v2)}|acc],
+                 delete(rest, k), :lists.keydelete(k, 1, original), fun)
      false ->
-        do_merge(tail, [{key, value2} | acc], rest, original, fun, keywords2)
+        do_merge(t, [{k, v2}|acc], rest, original, fun)
    end
  end

-  defp do_merge([], acc, rest, _original, _fun, _keywords2) do
+  defp do_merge([], acc, rest, _original, _fun) do
    rest ++ :lists.reverse(acc)
  end

-  defp do_merge(_other, _acc, _rest, _original, _fun, keywords2) do
-    raise ArgumentError,
-      message: "expected a keyword list as the second argument, got: #{inspect(keywords2)}"
-  end
-
  @doc """
  Returns whether a given `key` exists in the given `keywords`.

@@ -828,12 +635,12 @@ defmodule Keyword do
    update!(keywords, key, fun, keywords)
  end

-  defp update!([{key, value} | keywords], key, fun, _dict) do
-    [{key, fun.(value)} | delete(keywords, key)]
+  defp update!([{key, value}|keywords], key, fun, _dict) do
+    [{key, fun.(value)}|delete(keywords, key)]
  end

-  defp update!([{_, _} = e | keywords], key, fun, dict) do
-    [e | update!(keywords, key, fun, dict)]
+  defp update!([{_, _} = e|keywords], key, fun, dict) do
+    [e|update!(keywords, key, fun, dict)]
  end

  defp update!([], key, _fun, dict) when is_atom(key) do
@@ -861,12 +668,12 @@ defmodule Keyword do
  @spec update(t, key, value, (value -> value)) :: t
  def update(keywords, key, initial, fun)

-  def update([{key, value} | keywords], key, _initial, fun) do
-    [{key, fun.(value)} | delete(keywords, key)]
+  def update([{key, value}|keywords], key, _initial, fun) do
+    [{key, fun.(value)}|delete(keywords, key)]
  end

-  def update([{_, _} = e | keywords], key, initial, fun) do
-    [e | update(keywords, key, initial, fun)]
+  def update([{_, _} = e|keywords], key, initial, fun) do
+    [e|update(keywords, key, initial, fun)]
  end

  def update([], key, initial, _fun) when is_atom(key) do
@@ -879,7 +686,7 @@ defmodule Keyword do

  Returns a tuple with the new list and the old list with removed keys.

-  Keys for which there are no entries in the keyword list are ignored.
+  Keys for which there are no entires in the keyword list are ignored.

  Entries with duplicated keys end up in the same keyword list.

@@ -891,12 +698,11 @@ defmodule Keyword do
      {[a: 1, c: 3, a: 4], [b: 2]}

  """
-  @spec split(t, [key]) :: {t, t}
  def split(keywords, keys) when is_list(keywords) do
    fun = fn {k, v}, {take, drop} ->
      case k in keys do
-        true -> {[{k, v} | take], drop}
-        false -> {take, [{k, v} | drop]}
+        true  -> {[{k, v}|take], drop}
+        false -> {take, [{k, v}|drop]}
      end
    end

@@ -919,7 +725,6 @@ defmodule Keyword do
      [a: 1, c: 3, a: 5]

  """
-  @spec take(t, [key]) :: t
  def take(keywords, keys) when is_list(keywords) do
    :lists.filter(fn {k, _} -> k in keys end, keywords)
  end
@@ -937,9 +742,8 @@ defmodule Keyword do
      [a: 1, c: 3, a: 5]

  """
-  @spec drop(t, [key]) :: t
  def drop(keywords, keys) when is_list(keywords) do
-    :lists.filter(fn {key, _} -> key not in keys end, keywords)
+    :lists.filter(fn {k, _} -> not k in keys end, keywords)
  end

  @doc """
@@ -965,7 +769,6 @@ defmodule Keyword do
    case fetch(keywords, key) do
      {:ok, value} ->
        {value, delete(keywords, key)}
-
      :error ->
        {default, keywords}
    end
@@ -999,7 +802,6 @@ defmodule Keyword do
    case fetch(keywords, key) do
      {:ok, value} ->
        {value, delete(keywords, key)}
-
      :error ->
        {fun.(), keywords}
    end
@@ -1012,13 +814,13 @@ defmodule Keyword do

  ## Examples

-      iex> Keyword.pop_first([a: 1], :a)
+      iex> Keyword.pop_first [a: 1], :a
      {1, []}
-      iex> Keyword.pop_first([a: 1], :b)
+      iex> Keyword.pop_first [a: 1], :b
      {nil, [a: 1]}
-      iex> Keyword.pop_first([a: 1], :b, 3)
+      iex> Keyword.pop_first [a: 1], :b, 3
      {3, [a: 1]}
-      iex> Keyword.pop_first([a: 1, a: 2], :a)
+      iex> Keyword.pop_first [a: 1, a: 2], :a
      {1, [a: 2]}

  """
@@ -1039,14 +841,13 @@ defmodule Keyword do
      [a: 1]

  """
-  @spec to_list(t) :: t
  def to_list(keyword) when is_list(keyword) do
    keyword
  end

+  # TODO: Deprecate by 1.3
+  # TODO: Remove by 1.4
  @doc false
-  # TODO: Remove on 2.0
-  @deprecated "Use Kernel.length/1 instead"
  def size(keyword) do
    length(keyword)
  end
@@ -1,126 +1,67 @@
 defmodule List do
  @moduledoc """
-  Functions that work on (linked) lists.
+  Specialized functions that only work on lists.

-  Many of the functions provided for lists, which implement
-  the `Enumerable` protocol, are found in the `Enum` module.
+  In general, favor using the `Enum` API instead of `List`.

-  Additionally, the following functions and operators for lists are
-  found in `Kernel`:
+  Index access for list is linear. Negative indexes are also
+  supported but they imply the list will be iterated twice,
+  one to calculate the proper index and another to perform the
+  operation.

-    * `++/2`
-    * `--/2`
-    * `hd/1`
-    * `tl/1`
-    * `in/2`
-    * `length/1`
+  A decision was taken to delegate most functions to
+  Erlang's standard library but follow Elixir's convention
+  of receiving the subject (in this case, a list) as the
+  first argument.

-  Lists in Elixir are specified between square brackets:
+  ## Char lists

-      iex> [1, "two", 3, :four]
-      [1, "two", 3, :four]
-
-  Two lists can be concatenated and subtracted using the
-  `Kernel.++/2` and `Kernel.--/2` operators:
-
-      iex> [1, 2, 3] ++ [4, 5, 6]
-      [1, 2, 3, 4, 5, 6]
-      iex> [1, true, 2, false, 3, true] -- [true, false]
-      [1, 2, 3, true]
-
-  Lists in Elixir are effectively linked lists, which means
-  they are internally represented in pairs containing the
-  head and the tail of a list:
-
-      iex> [head | tail] = [1, 2, 3]
-      iex> head
-      1
-      iex> tail
-      [2, 3]
-
-  Similarly, we could write the list `[1, 2, 3]` using only
-  such pairs (called cons cells):
-
-      iex> [1 | [2 | [3 | []]]]
-      [1, 2, 3]
-
-  Some lists, called improper lists, do not have an empty list as
-  the second element in the last cons cell:
-
-      iex> [1 | [2 | [3 | 4]]]
-      [1, 2, 3 | 4]
-
-  Although improper lists are generally avoided, they are used in some
-  special circumstances like iodata and chardata entities (see the `IO` module).
-
-  Due to their cons cell based representation, prepending an element
-  to a list is always fast (constant time), while appending becomes
-  slower as the list grows in size (linear time):
-
-      iex> list = [1, 2, 3]
-      iex> [0 | list] # fast
-      [0, 1, 2, 3]
-      iex> list ++ [4] # slow
-      [1, 2, 3, 4]
-
-  Additonally, getting a list's length and accessing it by index are
-  linear time operations. Negative indexes are also supported but
-  they imply the list will be iterated twice, once to calculate the
-  proper index and another time to perform the operation.
-
-  ## Charlists
-
-  If a list is made of non-negative integers, it can also be called
-  a charlist. Elixir uses single quotes to define charlists:
+  If a list is made of non-negative integers, it can also
+  be called as a char list. Elixir uses single quotes to
+  define char lists:

      iex> 'héllo'
      [104, 233, 108, 108, 111]

-  In particular, charlists may be printed back in single
+  In particular, char lists may be printed back in single
  quotes if they contain only ASCII-printable codepoints:

      iex> 'abc'
      'abc'

  The rationale behind this behaviour is to better support
-  Erlang libraries which may return text as charlists
+  Erlang libraries which may return text as char lists
  instead of Elixir strings. One example of such functions
-  is `Application.loaded_applications/0`:
+  is `Application.loaded_applications`:

      Application.loaded_applications
      #=>  [{:stdlib, 'ERTS  CXC 138 10', '2.6'},
-      #=>   {:compiler, 'ERTS  CXC 138 10', '6.0.1'},
-      #=>   {:elixir, 'elixir', '1.0.0'},
-      #=>   {:kernel, 'ERTS  CXC 138 10', '4.1'},
-      #=>   {:logger, 'logger', '1.0.0'}]
-
-  A list can be checked if it is made of printable ascii
-  codepoints with `ascii_printable?/2`.
+            {:compiler, 'ERTS  CXC 138 10', '6.0.1'},
+            {:elixir, 'elixir', '1.0.0'},
+            {:kernel, 'ERTS  CXC 138 10', '4.1'},
+            {:logger, 'logger', '1.0.0'}]
  """

  @compile :inline_list_funcs

  @doc """
-  Deletes the given `item` from the `list`. Returns a new list without
-  the item.
-
-  If the `item` occurs more than once in the `list`, just
+  Deletes the given item from the list. Returns a list without
+  the item. If the item occurs more than once in the list, just
  the first occurrence is removed.

  ## Examples

-      iex> List.delete([:a, :b, :c], :a)
-      [:b, :c]
+      iex> List.delete([1, 2, 3], 1)
+      [2, 3]

-      iex> List.delete([:a, :b, :b, :c], :b)
-      [:a, :b, :c]
+      iex> List.delete([1, 2, 2, 3], 2)
+      [1, 2, 3]

  """
  @spec delete(list, any) :: list
-  def delete(list, item)
-  def delete([item | list], item), do: list
-  def delete([other | list], item), do: [other | delete(list, item)]
-  def delete([], _item), do: []
+  def delete(list, item) do
+    :lists.delete(item, list)
+  end

  @doc """
  Duplicates the given element `n` times in a list.
@@ -133,6 +74,7 @@ defmodule List do
      iex> List.duplicate([1, 2], 2)
      [[1, 2], [1, 2]]

+
  """
  @spec duplicate(elem, non_neg_integer) :: [elem] when elem: var
  def duplicate(elem, n) do
@@ -175,16 +117,16 @@ defmodule List do

  ## Examples

-      iex> List.foldl([5, 5], 10, fn x, acc -> x + acc end)
+      iex> List.foldl([5, 5], 10, fn (x, acc) -> x + acc end)
      20

-      iex> List.foldl([1, 2, 3, 4], 0, fn x, acc -> x - acc end)
+      iex> List.foldl([1, 2, 3, 4], 0, fn (x, acc) -> x - acc end)
      2

  """
  @spec foldl([elem], acc, (elem, acc -> acc)) :: acc when elem: var, acc: var
-  def foldl(list, acc, fun) when is_list(list) and is_function(fun) do
-    :lists.foldl(fun, acc, list)
+  def foldl(list, acc, function) when is_list(list) and is_function(function) do
+    :lists.foldl(function, acc, list)
  end

  @doc """
@@ -193,13 +135,13 @@ defmodule List do

  ## Examples

-      iex> List.foldr([1, 2, 3, 4], 0, fn x, acc -> x - acc end)
+      iex> List.foldr([1, 2, 3, 4], 0, fn (x, acc) -> x - acc end)
      -2

  """
  @spec foldr([elem], acc, (elem, acc -> acc)) :: acc when elem: var, acc: var
-  def foldr(list, acc, fun) when is_list(list) and is_function(fun) do
-    :lists.foldr(fun, acc, list)
+  def foldr(list, acc, function) when is_list(list) and is_function(function) do
+    :lists.foldr(function, acc, list)
  end

  @doc """
@@ -218,8 +160,8 @@ defmodule List do

  """
  @spec first([elem]) :: nil | elem when elem: var
-  def first([]), do: nil
-  def first([head | _]), do: head
+  def first([]),    do: nil
+  def first([h|_]), do: h

  @doc """
  Returns the last element in `list` or `nil` if `list` is empty.
@@ -237,9 +179,9 @@ defmodule List do

  """
  @spec last([elem]) :: nil | elem when elem: var
-  def last([]), do: nil
-  def last([head]), do: head
-  def last([_ | tail]), do: last(tail)
+  def last([]),    do: nil
+  def last([h]),   do: h
+  def last([_|t]), do: last(t)

  @doc """
  Receives a list of tuples and returns the first tuple
@@ -280,7 +222,7 @@ defmodule List do
      false

  """
-  @spec keymember?([tuple], any, non_neg_integer) :: boolean
+  @spec keymember?([tuple], any, non_neg_integer) :: any
  def keymember?(list, key, position) do
    :lists.keymember(key, position + 1, list)
  end
@@ -319,10 +261,9 @@ defmodule List do
  end

  @doc """
-  Receives a `list` of tuples and replaces the item
-  identified by `key` at `position`.
-
-  If the item does not exist, it is added to the end of the `list`.
+  Receives a list of tuples and replaces the item
+  identified by `key` at `position`. If the item
+  does not exist, it is added to the end of the list.

  ## Examples

@@ -339,7 +280,7 @@ defmodule List do
  end

  @doc """
-  Receives a `list` of tuples and deletes the first tuple
+  Receives a list of tuples and deletes the first tuple
  where the item at `position` matches the
  given `key`. Returns the new list.

@@ -383,15 +324,14 @@ defmodule List do
  def keytake(list, key, position) do
    case :lists.keytake(key, position + 1, list) do
      {:value, item, list} -> {item, list}
-      false -> nil
+      false                -> nil
    end
  end

  @doc """
-  Wraps `term` in a list if this is not list.
-
-  If `term` is already a list, it returns the list.
-  If `term` is `nil`, it returns an empty list.
+  Wraps the argument in a list.
+  If the argument is already a list, returns the list.
+  If the argument is `nil`, returns an empty list.

  ## Examples

@@ -405,11 +345,7 @@ defmodule List do
      []

  """
-  @spec wrap(nil) :: []
-  @spec wrap(list) :: list when list: maybe_improper_list()
-  @spec wrap(term) :: nonempty_list(term) when term: any()
-  def wrap(term)
-
+  @spec wrap(list | any) :: list
  def wrap(list) when is_list(list) do
    list
  end
@@ -438,92 +374,14 @@ defmodule List do
  """
  @spec zip([list]) :: [tuple]
  def zip([]), do: []
-
  def zip(list_of_lists) when is_list(list_of_lists) do
    do_zip(list_of_lists, [])
  end

-  @doc """
-  Checks if a list is a charlist made only of printable ASCII characters.
-
-  A printable charlist in Elixir contains only ASCII characters.
-
-  Takes an optional `limit` as a second argument. `ascii_printable?/2` only
-  checks the printability of the list up to the `limit`.
-
-  ## Examples
-
-      iex> List.ascii_printable?('abc')
-      true
-
-      iex> List.ascii_printable?('abc' ++ [0])
-      false
-
-      iex> List.ascii_printable?('abc' ++ [0], 2)
-      true
-
-  Improper lists are not printable, even if made only of ascii characters:
-
-      iex> List.ascii_printable?('abc' ++ ?d)
-      false
-
-  """
-  @doc since: "1.6.0"
-  def ascii_printable?(list, counter \\ :infinity)
-
-  def ascii_printable?(_, 0) do
-    true
-  end
-
-  def ascii_printable?([char | rest], counter)
-      when is_integer(char) and char >= 32 and char <= 126 do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\n | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\r | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\t | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\v | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\b | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\f | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\e | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([?\a | rest], counter) do
-    ascii_printable?(rest, decrement(counter))
-  end
-
-  def ascii_printable?([], _counter), do: true
-  def ascii_printable?(_, _counter), do: false
-
-  @compile {:inline, decrement: 1}
-  defp decrement(:infinity), do: :infinity
-  defp decrement(counter), do: counter - 1
-
  @doc """
  Returns a list with `value` inserted at the specified `index`.
-
  Note that `index` is capped at the list length. Negative indices
-  indicate an offset from the end of the `list`.
+  indicate an offset from the end of the list.

  ## Examples

@@ -541,7 +399,7 @@ defmodule List do

  """
  @spec insert_at(list, integer, any) :: list
-  def insert_at(list, index, value) when is_integer(index) do
+  def insert_at(list, index, value) do
    if index < 0 do
      do_insert_at(list, length(list) + index + 1, value)
    else
@@ -551,8 +409,7 @@ defmodule List do

  @doc """
  Returns a list with a replaced value at the specified `index`.
-
-  Negative indices indicate an offset from the end of the `list`.
+  Negative indices indicate an offset from the end of the list.
  If `index` is out of bounds, the original `list` is returned.

  ## Examples
@@ -571,7 +428,7 @@ defmodule List do

  """
  @spec replace_at(list, integer, any) :: list
-  def replace_at(list, index, value) when is_integer(index) do
+  def replace_at(list, index, value) do
    if index < 0 do
      do_replace_at(list, length(list) + index, value)
    else
@@ -581,8 +438,7 @@ defmodule List do

  @doc """
  Returns a list with an updated value at the specified `index`.
-
-  Negative indices indicate an offset from the end of the `list`.
+  Negative indices indicate an offset from the end of the list.
  If `index` is out of bounds, the original `list` is returned.

  ## Examples
@@ -601,7 +457,7 @@ defmodule List do

  """
  @spec update_at([elem], integer, (elem -> any)) :: list when elem: var
-  def update_at(list, index, fun) when is_function(fun, 1) and is_integer(index) do
+  def update_at(list, index, fun) do
    if index < 0 do
      do_update_at(list, length(list) + index, fun)
    else
@@ -611,8 +467,7 @@ defmodule List do

  @doc """
  Produces a new list by removing the value at the specified `index`.
-
-  Negative indices indicate an offset from the end of the `list`.
+  Negative indices indicate an offset from the end of the list.
  If `index` is out of bounds, the original `list` is returned.

  ## Examples
@@ -628,72 +483,18 @@ defmodule List do

  """
  @spec delete_at(list, integer) :: list
-  def delete_at(list, index) when is_integer(index) do
-    elem(pop_at(list, index), 1)
-  end
-
-  @doc """
-  Returns and removes the value at the specified `index` in the `list`.
-
-  Negative indices indicate an offset from the end of the `list`.
-  If `index` is out of bounds, the original `list` is returned.
-
-  ## Examples
-
-      iex> List.pop_at([1, 2, 3], 0)
-      {1, [2, 3]}
-      iex> List.pop_at([1, 2, 3], 5)
-      {nil, [1, 2, 3]}
-      iex> List.pop_at([1, 2, 3], 5, 10)
-      {10, [1, 2, 3]}
-      iex> List.pop_at([1, 2, 3], -1)
-      {3, [1, 2]}
-
-  """
-  @doc since: "1.4.0"
-  @spec pop_at(list, integer, any) :: {any, list}
-  def pop_at(list, index, default \\ nil) when is_integer(index) do
+  def delete_at(list, index) do
    if index < 0 do
-      do_pop_at(list, length(list) + index, default, [])
+      do_delete_at(list, length(list) + index)
    else
-      do_pop_at(list, index, default, [])
+      do_delete_at(list, index)
    end
  end

  @doc """
-  Returns `true` if `list` starts with the given `prefix` list; otherwise returns `false`.
+  Converts a char list to an atom.

-  If `prefix` is an empty list, it returns `true`.
-
-  ### Examples
-
-      iex> List.starts_with?([1, 2, 3], [1, 2])
-      true
-
-      iex> List.starts_with?([1, 2], [1, 2, 3])
-      false
-
-      iex> List.starts_with?([:alpha], [])
-      true
-
-      iex> List.starts_with?([], [:alpha])
-      false
-
-  """
-  @doc since: "1.5.0"
-  @spec starts_with?(list, list) :: boolean
-  @spec starts_with?(list, []) :: true
-  @spec starts_with?([], nonempty_list) :: false
-  def starts_with?(list, prefix)
-
-  def starts_with?([head | tail], [head | prefix_tail]), do: starts_with?(tail, prefix_tail)
-  def starts_with?(list, []) when is_list(list), do: true
-  def starts_with?(list, [_ | _]) when is_list(list), do: false
-
-  @doc """
-  Converts a charlist to an atom.
-
-  Currently Elixir does not support conversions from charlists
+  Currently Elixir does not support conversions from char lists
  which contains Unicode codepoints greater than 0xFF.

  Inlined by the compiler.
@@ -704,16 +505,16 @@ defmodule List do
      :elixir

  """
-  @spec to_atom(charlist) :: atom
-  def to_atom(charlist) do
-    :erlang.list_to_atom(charlist)
+  @spec to_atom(char_list) :: atom
+  def to_atom(char_list) do
+    :erlang.list_to_atom(char_list)
  end

  @doc """
-  Converts a charlist to an existing atom. Raises an `ArgumentError`
+  Converts a char list to an existing atom. Raises an `ArgumentError`
  if the atom does not exist.

-  Currently Elixir does not support conversions from charlists
+  Currently Elixir does not support conversions from char lists
  which contains Unicode codepoints greater than 0xFF.

  Inlined by the compiler.
@@ -728,13 +529,13 @@ defmodule List do
      ** (ArgumentError) argument error

  """
-  @spec to_existing_atom(charlist) :: atom
-  def to_existing_atom(charlist) do
-    :erlang.list_to_existing_atom(charlist)
+  @spec to_existing_atom(char_list) :: atom
+  def to_existing_atom(char_list) do
+    :erlang.list_to_existing_atom(char_list)
  end

  @doc """
-  Returns the float whose text representation is `charlist`.
+  Returns the float whose text representation is `char_list`.

  Inlined by the compiler.

@@ -744,13 +545,13 @@ defmodule List do
      2.2017764

  """
-  @spec to_float(charlist) :: float
-  def to_float(charlist) do
-    :erlang.list_to_float(charlist)
+  @spec to_float(char_list) :: float
+  def to_float(char_list) do
+    :erlang.list_to_float(char_list)
  end

  @doc """
-  Returns an integer whose text representation is `charlist`.
+  Returns an integer whose text representation is `char_list`.

  Inlined by the compiler.

@@ -760,13 +561,13 @@ defmodule List do
      123

  """
-  @spec to_integer(charlist) :: integer
-  def to_integer(charlist) do
-    :erlang.list_to_integer(charlist)
+  @spec to_integer(char_list) :: integer
+  def to_integer(char_list) do
+    :erlang.list_to_integer(char_list)
  end

  @doc """
-  Returns an integer whose text representation is `charlist` in base `base`.
+  Returns an integer whose text representation is `char_list` in base `base`.

  Inlined by the compiler.

@@ -776,9 +577,9 @@ defmodule List do
      1023

  """
-  @spec to_integer(charlist, 2..36) :: integer
-  def to_integer(charlist, base) do
-    :erlang.list_to_integer(charlist, base)
+  @spec to_integer(char_list, 2..36) :: integer
+  def to_integer(char_list, base) do
+    :erlang.list_to_integer(char_list, base)
  end

  @doc """
@@ -813,29 +614,14 @@ defmodule List do
      iex> List.to_string([0x0061, "bc"])
      "abc"

-      iex> List.to_string([0x0064, "ee", ['p']])
-      "deep"
-
  """
-  @spec to_string(:unicode.charlist()) :: String.t()
+  @spec to_string(:unicode.charlist) :: String.t
  def to_string(list) when is_list(list) do
    try do
-      :unicode.characters_to_binary(list)
+       :unicode.characters_to_binary(list)
    rescue
      ArgumentError ->
-        raise ArgumentError, """
-        cannot convert the given list to a string.
-
-        To be converted to a string, a list must contain only:
-
-          * strings
-          * integers representing Unicode codepoints
-          * or a list containing one of these three elements
-
-        Please check the given list or call inspect/1 to get the list representation, got:
-
-        #{inspect(list)}
-        """
+        raise ArgumentError, "cannot convert list to string. The list must contain only integers, strings or nested such lists; got: #{inspect list}"
    else
      result when is_binary(result) ->
        result
@@ -848,112 +634,6 @@ defmodule List do
    end
  end

-  @doc """
-  Returns a keyword list that represents an *edit script*.
-
-  The algorithm is outlined in the
-  "An O(ND) Difference Algorithm and Its Variations" paper by E. Myers.
-
-  An *edit script* is a keyword list. Each key describes the "editing action" to
-  take in order to bring `list1` closer to being equal to `list2`; a key can be
-  `:eq`, `:ins`, or `:del`. Each value is a sublist of either `list1` or `list2`
-  that should be inserted (if the corresponding key `:ins`), deleted (if the
-  corresponding key is `:del`), or left alone (if the corresponding key is
-  `:eq`) in `list1` in order to be closer to `list2`.
-
-  ## Examples
-
-      iex> List.myers_difference([1, 4, 2, 3], [1, 2, 3, 4])
-      [eq: [1], del: [4], eq: [2, 3], ins: [4]]
-
-  """
-  @doc since: "1.4.0"
-  @spec myers_difference(list, list) :: [{:eq | :ins | :del, list}]
-  def myers_difference(list1, list2) when is_list(list1) and is_list(list2) do
-    path = {0, list1, list2, []}
-    find_script(0, length(list1) + length(list2), [path])
-  end
-
-  defp find_script(envelope, max, paths) do
-    case each_diagonal(-envelope, envelope, paths, []) do
-      {:done, edits} -> compact_reverse(edits, [])
-      {:next, paths} -> find_script(envelope + 1, max, paths)
-    end
-  end
-
-  defp compact_reverse([], acc), do: acc
-
-  defp compact_reverse([{kind, elem} | rest], [{kind, result} | acc]) do
-    compact_reverse(rest, [{kind, [elem | result]} | acc])
-  end
-
-  defp compact_reverse(rest, [{:eq, elem}, {:ins, elem}, {:eq, other} | acc]) do
-    compact_reverse(rest, [{:ins, elem}, {:eq, elem ++ other} | acc])
-  end
-
-  defp compact_reverse([{kind, elem} | rest], acc) do
-    compact_reverse(rest, [{kind, [elem]} | acc])
-  end
-
-  defp each_diagonal(diag, limit, _paths, next_paths) when diag > limit do
-    {:next, :lists.reverse(next_paths)}
-  end
-
-  defp each_diagonal(diag, limit, paths, next_paths) do
-    {path, rest} = proceed_path(diag, limit, paths)
-
-    case follow_snake(path) do
-      {:cont, path} -> each_diagonal(diag + 2, limit, rest, [path | next_paths])
-      {:done, edits} -> {:done, edits}
-    end
-  end
-
-  defp proceed_path(0, 0, [path]), do: {path, []}
-
-  defp proceed_path(diag, limit, [path | _] = paths) when diag == -limit do
-    {move_down(path), paths}
-  end
-
-  defp proceed_path(diag, limit, [path]) when diag == limit do
-    {move_right(path), []}
-  end
-
-  defp proceed_path(_diag, _limit, [path1, path2 | rest]) do
-    if elem(path1, 0) > elem(path2, 0) do
-      {move_right(path1), [path2 | rest]}
-    else
-      {move_down(path2), [path2 | rest]}
-    end
-  end
-
-  defp move_right({y, list1, [elem | rest], edits}) do
-    {y, list1, rest, [{:ins, elem} | edits]}
-  end
-
-  defp move_right({y, list1, [], edits}) do
-    {y, list1, [], edits}
-  end
-
-  defp move_down({y, [elem | rest], list2, edits}) do
-    {y + 1, rest, list2, [{:del, elem} | edits]}
-  end
-
-  defp move_down({y, [], list2, edits}) do
-    {y + 1, [], list2, edits}
-  end
-
-  defp follow_snake({y, [elem | rest1], [elem | rest2], edits}) do
-    follow_snake({y + 1, rest1, rest2, [{:eq, elem} | edits]})
-  end
-
-  defp follow_snake({_y, [], [], edits}) do
-    {:done, edits}
-  end
-
-  defp follow_snake(path) do
-    {:cont, path}
-  end
-
  ## Helpers

  # replace_at
@@ -970,8 +650,8 @@ defmodule List do
    [value | rest]
  end

-  defp do_replace_at([head | tail], index, value) do
-    [head | do_replace_at(tail, index - 1, value)]
+  defp do_replace_at([h | t], index, value) do
+    [h | do_replace_at(t, index - 1, value)]
  end

  # insert_at
@@ -984,8 +664,8 @@ defmodule List do
    [value | list]
  end

-  defp do_insert_at([head | tail], index, value) do
-    [head | do_insert_at(tail, index - 1, value)]
+  defp do_insert_at([h | t], index, value) do
+    [h | do_insert_at(t, index - 1, value)]
  end

  # update_at
@@ -998,41 +678,38 @@ defmodule List do
    list
  end

-  defp do_update_at([head | tail], index, fun) do
-    [head | do_update_at(tail, index - 1, fun)]
+  defp do_update_at([h | t], index, fun) do
+    [h | do_update_at(t, index - 1, fun)]
  end

  defp do_update_at([], _index, _fun) do
    []
  end

-  # pop_at
+  # delete_at

-  defp do_pop_at([], _index, default, acc) do
-    {default, :lists.reverse(acc)}
+  defp do_delete_at([], _index) do
+    []
  end

-  defp do_pop_at(list, index, default, []) when index < 0 do
-    {default, list}
+  defp do_delete_at([_ | t], 0) do
+    t
  end

-  defp do_pop_at([head | tail], 0, _default, acc) do
-    {head, :lists.reverse(acc, tail)}
+  defp do_delete_at(list, index) when index < 0 do
+    list
  end

-  defp do_pop_at([head | tail], index, default, acc) do
-    do_pop_at(tail, index - 1, default, [head | acc])
+  defp do_delete_at([h | t], index) do
+    [h | do_delete_at(t, index - 1)]
  end

  # zip

  defp do_zip(list, acc) do
    converter = fn x, acc -> do_zip_each(to_list(x), acc) end
-
    case :lists.mapfoldl(converter, [], list) do
-      {_, nil} ->
-        :lists.reverse(acc)
-
+      {_, nil} -> :lists.reverse(acc)
      {mlist, heads} ->
        do_zip(mlist, [to_tuple(:lists.reverse(heads)) | acc])
    end
@@ -1042,8 +719,8 @@ defmodule List do
    {nil, nil}
  end

-  defp do_zip_each([head | tail], acc) do
-    {tail, [head | acc]}
+  defp do_zip_each([h | t], acc) do
+    {t, [h | acc]}
  end

  defp do_zip_each([], _) do
@@ -1051,5 +728,5 @@ defmodule List do
  end

  defp to_list(tuple) when is_tuple(tuple), do: Tuple.to_list(tuple)
-  defp to_list(list) when is_list(list), do: list
+  defp to_list(list)  when is_list(list),   do: list
 end
@@ -1,62 +1,56 @@
 defprotocol List.Chars do
  @moduledoc ~S"""
-  The `List.Chars` protocol is responsible for
-  converting a structure to a charlist (only if applicable).
-
+  The List.Chars protocol is responsible for
+  converting a structure to a list (only if applicable).
  The only function required to be implemented is
-  `to_charlist/1` which does the conversion.
+  `to_char_list` which does the conversion.

-  The `to_charlist/1` function automatically imported
-  by `Kernel` invokes this protocol.
+  The `to_char_list` function automatically imported
+  by Kernel invokes this protocol.
  """

-  @doc """
-  Converts `term` to a charlist.
-  """
-  @spec to_charlist(t) :: charlist
-  def to_charlist(term)
-
-  @doc false
-  # TODO: Remove by 2.0
-  @deprecated "Use List.Chars.to_charlist/1 instead"
-  Kernel.def to_char_list(term) do
-    __MODULE__.to_charlist(term)
-  end
+  def to_char_list(thing)
 end

 defimpl List.Chars, for: Atom do
-  def to_charlist(atom), do: Atom.to_charlist(atom)
+  def to_char_list(atom), do: Atom.to_char_list(atom)
 end

 defimpl List.Chars, for: BitString do
  @doc """
-  Returns the given binary `term` converted to a charlist.
+  Returns the given binary converted to a char list.
  """
-  def to_charlist(term) when is_binary(term) do
-    String.to_charlist(term)
+  def to_char_list(thing) when is_binary(thing) do
+    String.to_char_list(thing)
  end

-  def to_charlist(term) do
+  def to_char_list(thing) do
    raise Protocol.UndefinedError,
-      protocol: @protocol,
-      value: term,
-      description: "cannot convert a bitstring to a charlist"
+             protocol: @protocol,
+                value: thing,
+          description: "cannot convert a bitstring to a char list"
  end
 end

 defimpl List.Chars, for: List do
-  # Note that same inlining is used for the rewrite rule.
-  def to_charlist(list), do: list
+  def to_char_list(list), do: list
 end

 defimpl List.Chars, for: Integer do
-  def to_charlist(term) do
-    Integer.to_charlist(term)
+  def to_char_list(thing) do
+    Integer.to_char_list(thing)
  end
 end

 defimpl List.Chars, for: Float do
-  def to_charlist(term) do
-    :io_lib_format.fwrite_g(term)
+  @digits 20
+  @limit  :math.pow(10, @digits)
+
+  def to_char_list(thing) when thing > @limit do
+    Float.to_char_list(thing, scientific: @digits)
+  end
+
+  def to_char_list(thing) do
+    Float.to_char_list(thing, compact: true, decimals: @digits)
  end
 end
@@ -3,8 +3,8 @@ defmodule Macro.Env do
  A struct that holds compile time environment information.

  The current environment can be accessed at any time as
-  `__ENV__/0`. Inside macros, the caller environment can be
-  accessed as `__CALLER__/0`.
+  `__ENV__`. Inside macros, the caller environment can be
+  accessed as `__CALLER__`.

  An instance of `Macro.Env` must not be modified by hand. If you need to
  create a custom environment to pass to `Code.eval_quoted/3`, use the
@@ -29,28 +29,19 @@ defmodule Macro.Env do
      `nil` if not inside a function
    * `context` - the context of the environment; it can be `nil`
      (default context), inside a guard or inside a match
-    * `aliases` -  a list of two-element tuples, where the first
-      element is the aliased name and the second one the actual name
+    * `aliases` -  a list of two-item tuples, where the first
+      item is the aliased name and the second the actual name
    * `requires` - the list of required modules
    * `functions` - a list of functions imported from each module
    * `macros` - a list of macros imported from each module
    * `macro_aliases` - a list of aliases defined inside the current macro
    * `context_modules` - a list of modules defined in the current context
+    * `vars` - a list keeping all defined variables as `{var, context}`
+    * `export_vars` - a list keeping all variables to be exported in a
+      construct (may be `nil`)
    * `lexical_tracker` - PID of the lexical tracker which is responsible for
      keeping user info
-
-  The following fields pertain to variable handling and must not be accessed or
-  relied on. To get a list of all variables, see `vars/1`:
-
-    * `current_vars`
-    * `unused_vars`
-    * `prematch_vars`
-    * `contextual_vars`
-
-  The following fields are deprecated and must not be accessed or relied on:
-
-    * `vars` - a list keeping all defined variables as `{var, context}`
-
+    * `local` - the module to expand local functions to
  """

  @type name_arity :: {atom, arity}
@@ -63,42 +54,30 @@ defmodule Macro.Env do
  @type functions :: [{module, [name_arity]}]
  @type macros :: [{module, [name_arity]}]
  @type context_modules :: [module]
-  @type lexical_tracker :: pid | nil
-  @type var :: {atom, atom | non_neg_integer}
+  @type vars :: [{atom, atom | non_neg_integer}]
+  @type export_vars :: vars | nil
+  @type lexical_tracker :: pid
+  @type local :: atom | nil

-  @typep vars :: [var]
-  @typep var_type :: :term
-  @typep var_version :: non_neg_integer
-  @typep unused_vars :: %{{var, var_version} => non_neg_integer | false}
-  @typep current_vars :: %{var => {var_version, var_type}}
-  @typep prematch_vars :: current_vars | :warn | :raise | :pin | :apply
-  @typep contextual_vars :: [atom]
+  @type t :: %{__struct__: __MODULE__,
+               module: atom,
+               file: file,
+               line: line,
+               function: name_arity | nil,
+               context: context,
+               requires: requires,
+               aliases: aliases,
+               functions: functions,
+               macros: macros,
+               macro_aliases: aliases,
+               context_modules: context_modules,
+               vars: vars,
+               export_vars: export_vars,
+               lexical_tracker: lexical_tracker,
+               local: local}

-  @type t :: %{
-          __struct__: __MODULE__,
-          module: atom,
-          file: file,
-          line: line,
-          function: name_arity | nil,
-          context: context,
-          requires: requires,
-          aliases: aliases,
-          functions: functions,
-          macros: macros,
-          macro_aliases: aliases,
-          context_modules: context_modules,
-          vars: vars,
-          unused_vars: unused_vars,
-          current_vars: current_vars,
-          prematch_vars: prematch_vars,
-          lexical_tracker: lexical_tracker,
-          contextual_vars: contextual_vars
-        }
-
-  # TODO: Remove :vars field on v2.0
  def __struct__ do
-    %{
-      __struct__: __MODULE__,
+    %{__struct__: __MODULE__,
      module: nil,
      file: "nofile",
      line: 0,
@@ -111,68 +90,20 @@ defmodule Macro.Env do
      macro_aliases: [],
      context_modules: [],
      vars: [],
-      unused_vars: %{},
-      current_vars: %{},
-      prematch_vars: :warn,
-      lexical_tracker: nil,
-      contextual_vars: []
-    }
-  end
-
-  def __struct__(kv) do
-    Enum.reduce(kv, __struct__(), fn {k, v}, acc -> :maps.update(k, v, acc) end)
-  end
-
-  @doc """
-  Returns a list of variables in the current environment.
-
-  Each variable is identified by a tuple of two elements,
-  where the first element is the variable name as an atom
-  and the second element is its context, which may be an
-  atom or an integer.
-  """
-  @doc since: "1.7.0"
-  @spec vars(t) :: [var]
-  def vars(env)
-
-  def vars(%{__struct__: Macro.Env, current_vars: current_vars}) do
-    Map.keys(current_vars)
-  end
-
-  @doc """
-  Checks if a variable belongs to the environment.
-  """
-  @doc since: "1.7.0"
-  @spec has_var?(t, var) :: boolean()
-  def has_var?(env, var)
-
-  def has_var?(%{__struct__: Macro.Env, current_vars: current_vars}, var) do
-    Map.has_key?(current_vars, var)
+      export_vars: nil,
+      lexical_tracker: nil}
  end

  @doc """
  Returns a keyword list containing the file and line
  information as keys.
  """
-  @spec location(t) :: keyword
+  @spec location(t) :: Keyword.t
  def location(env)
-
  def location(%{__struct__: Macro.Env, file: file, line: line}) do
    [file: file, line: line]
  end

-  @doc """
-  Returns a `Macro.Env` in the match context.
-  """
-  @spec to_match(t) :: t
-  def to_match(%{__struct__: Macro.Env, context: :match} = env) do
-    env
-  end
-
-  def to_match(%{__struct__: Macro.Env, current_vars: vars} = env) do
-    %{env | context: :match, prematch_vars: vars}
-  end
-
  @doc """
  Returns whether the compilation environment is currently
  inside a guard.
@@ -197,10 +128,8 @@ defmodule Macro.Env do
    cond do
      is_nil(env.module) ->
        [{:elixir_compiler, :__FILE__, 1, relative_location(env)}]
-
      is_nil(env.function) ->
        [{env.module, :__MODULE__, 0, relative_location(env)}]
-
      true ->
        {name, arity} = env.function
        [{env.module, name, arity, relative_location(env)}]
@@ -208,6 +137,6 @@ defmodule Macro.Env do
  end

  defp relative_location(env) do
-    [file: String.to_charlist(Path.relative_to_cwd(env.file)), line: env.line]
+    [file: Path.relative_to_cwd(env.file), line: env.line]
  end
 end
@@ -2,105 +2,18 @@ defmodule Map do
  @moduledoc """
  A set of functions for working with maps.

-  Many functions for maps, which implement the `Enumerable` protocol,
-  are found in the `Enum` module. Additionally, the following functions
-  for maps are found in `Kernel`:
-
-    * `map_size/1`
-
-  Maps are the "go to" key-value data structure in Elixir. Maps can be created
-  with the `%{}` syntax, and key-value pairs can be expressed as `key => value`:
-
-      iex> %{}
-      %{}
-      iex> %{"one" => :two, 3 => "four"}
-      %{3 => "four", "one" => :two}
-
-  Key-value pairs in a map do not follow any order (that's why the printed map
-  in the example above has a different order than the map that was created).
-
-  Maps do not impose any restriction on the key type: anything can be a key in a
-  map. As a key-value structure, maps do not allow duplicated keys. Keys are
-  compared using the exact-equality operator (`===/2`). If colliding keys are defined
-  in a map literal, the last one prevails.
-
-  When the key in a key-value pair is an atom, the `key: value` shorthand syntax
-  can be used (as in many other special forms), provided key-value pairs are put at
-  the end:
-
-      iex> %{"hello" => "world", a: 1, b: 2}
-      %{:a => 1, :b => 2, "hello" => "world"}
-
-  Keys in maps can be accessed through some of the functions in this module
-  (such as `Map.get/3` or `Map.fetch/2`) or through the `map[]` syntax provided
-  by the `Access` module:
-
-      iex> map = %{a: 1, b: 2}
-      iex> Map.fetch(map, :a)
-      {:ok, 1}
-      iex> map[:b]
-      2
-      iex> map["non_existing_key"]
-      nil
-
-  For accessing atom keys, one may also `map.key`. Note that while `map[key]` will
-  return `nil` if `map` doesn't contain `key`, `map.key` will raise if `map` doesn't
-  contain the key `:key`.
-
-      iex> map = %{foo: "bar", baz: "bong"}
-      iex> map.foo
-      "bar"
-      iex> map.non_existing_key
-      ** (KeyError) key :non_existing_key not found in: %{baz: "bong", foo: "bar"}
-
-  The two syntaxes for accessing keys reveal the dual nature of maps. The `map[key]`
-  syntax is used for dynamically created maps that may have any key, of any type.
-  `map.key` is used with maps that hold a predetermined set of atoms keys, which are
-  expected to always be present. Structs, defined via `defstruct/1`, are one example
-  of such "static maps", where the keys can also be checked during compile time.
-
-  Maps can be pattern matched on. When a map is on the left-hand side of a
-  pattern match, it will match if the map on the right-hand side contains the
-  keys on the left-hand side and their values match the ones on the left-hand
-  side. This means that an empty map matches every map.
-
-      iex> %{} = %{foo: "bar"}
-      %{foo: "bar"}
-      iex> %{a: a} = %{:a => 1, "b" => 2, [:c, :e, :e] => 3}
-      iex> a
-      1
-      iex> %{:c => 3} = %{:a => 1, 2 => :b}
-      ** (MatchError) no match of right hand side value: %{2 => :b, :a => 1}
-
-  Variables can be used as map keys both when writing map literals as well as
-  when matching:
-
-      iex> n = 1
-      1
-      iex> %{n => :one}
-      %{1 => :one}
-      iex> %{^n => :one} = %{1 => :one, 2 => :two, 3 => :three}
-      %{1 => :one, 2 => :two, 3 => :three}
-
-  Maps also support a specific update syntax to update the value stored under
-  *existing* atom keys:
-
-      iex> map = %{one: 1, two: 2}
-      iex> %{map | one: "one"}
-      %{one: "one", two: 2}
-      iex> %{map | three: 3}
-      ** (KeyError) key :three not found
-
+  Maps are key-value stores where keys can be any value and
+  are compared using the match operator (`===`). Maps can be
+  created with the `%{}` special form defined in the
+  `Kernel.SpecialForms` module.
  """

  @type key :: any
  @type value :: any
-  @compile {:inline, fetch: 2, fetch!: 2, get: 2, put: 3, delete: 2, has_key?: 2, replace!: 3}
+  @compile {:inline, fetch: 2, put: 3, delete: 2, has_key?: 2}

  @doc """
-  Returns all keys from `map`.
-
-  Inlined by the compiler.
+  Returns all keys from the map.

  ## Examples

@@ -112,9 +25,7 @@ defmodule Map do
  defdelegate keys(map), to: :maps

  @doc """
-  Returns all values from `map`.
-
-  Inlined by the compiler.
+  Returns all values from the map.

  ## Examples

@@ -126,12 +37,7 @@ defmodule Map do
  defdelegate values(map), to: :maps

  @doc """
-  Converts `map` to a list.
-
-  Each key-value pair in the map is converted to a two-element tuple `{key,
-  value}` in the resulting list.
-
-  Inlined by the compiler.
+  Converts the map to a list.

  ## Examples

@@ -149,7 +55,7 @@ defmodule Map do

  ## Examples

-      iex> Map.new()
+      iex> Map.new
      %{}

  """
@@ -157,7 +63,7 @@ defmodule Map do
  def new, do: %{}

  @doc """
-  Creates a map from an `enumerable`.
+  Creates a map from an enumerable.

  Duplicated keys are removed; the latest one prevails.

@@ -169,23 +75,15 @@ defmodule Map do
      %{a: 3}

  """
-  @spec new(Enumerable.t()) :: map
-  def new(enumerable)
-  def new(list) when is_list(list), do: :maps.from_list(list)
-  def new(%_{} = struct), do: new_from_enum(struct)
-  def new(%{} = map), do: map
-  def new(enum), do: new_from_enum(enum)
-
-  defp new_from_enum(enumerable) do
-    enumerable
-    |> Enum.to_list()
-    |> :maps.from_list()
+  @spec new(Enum.t) :: map
+  def new(enumerable) do
+    Enum.reduce(enumerable, %{}, fn {k, v}, acc -> put(acc, k, v) end)
  end

  @doc """
-  Creates a map from an `enumerable` via the given transformation function.
+  Creates a map from an enumerable via the transformation function.

-  Duplicated keys are removed; the latest one prevails.
+  Duplicated entries are removed; the latest one prevails.

  ## Examples

@@ -193,27 +91,17 @@ defmodule Map do
      %{a: :a, b: :b}

  """
-  @spec new(Enumerable.t(), (term -> {key, value})) :: map
-  def new(enumerable, transform) when is_function(transform, 1) do
-    enumerable
-    |> Enum.to_list()
-    |> new_transform(transform, [])
-  end
-
-  defp new_transform([], _fun, acc) do
-    acc
-    |> :lists.reverse()
-    |> :maps.from_list()
-  end
-
-  defp new_transform([item | rest], fun, acc) do
-    new_transform(rest, fun, [fun.(item) | acc])
+  @spec new(Enum.t, (term -> {key, value})) :: map
+  def new(enumerable, transform) do
+    fun = fn el, acc ->
+      {k, v} = transform.(el)
+      put(acc, k, v)
+    end
+    Enum.reduce(enumerable, %{}, fun)
  end

  @doc """
-  Returns whether the given `key` exists in the given `map`.
-
-  Inlined by the compiler.
+  Returns whether a given `key` exists in the given `map`.

  ## Examples

@@ -227,12 +115,9 @@ defmodule Map do
  def has_key?(map, key), do: :maps.is_key(key, map)

  @doc """
-  Fetches the value for a specific `key` in the given `map`.
+  Fetches the value for a specific `key` and returns it in a tuple.

-  If `map` contains the given `key` with value `value`, then `{:ok, value}` is
-  returned. If `map` doesn't contain `key`, `:error` is returned.
-
-  Inlined by the compiler.
+  If the `key` does not exist, returns `:error`.

  ## Examples

@@ -246,13 +131,9 @@ defmodule Map do
  def fetch(map, key), do: :maps.find(key, map)

  @doc """
-  Fetches the value for a specific `key` in the given `map`, erroring out if
-  `map` doesn't contain `key`.
+  Fetches the value for specific `key`.

-  If `map` contains the given `key`, the corresponding value is returned. If
-  `map` doesn't contain `key`, a `KeyError` exception is raised.
-
-  Inlined by the compiler.
+  If `key` does not exist, a `KeyError` is raised.

  ## Examples

@@ -264,80 +145,38 @@ defmodule Map do
  """
  @spec fetch!(map, key) :: value | no_return
  def fetch!(map, key) do
-    :maps.get(key, map)
+    case fetch(map, key) do
+      {:ok, value} -> value
+      :error -> raise KeyError, key: key, term: map
+    end
  end

  @doc """
  Puts the given `value` under `key` unless the entry `key`
-  already exists in `map`.
+  already exists.

  ## Examples

      iex> Map.put_new(%{a: 1}, :b, 2)
-      %{a: 1, b: 2}
+      %{b: 2, a: 1}
      iex> Map.put_new(%{a: 1, b: 2}, :a, 3)
      %{a: 1, b: 2}

  """
  @spec put_new(map, key, value) :: map
  def put_new(map, key, value) do
-    case map do
-      %{^key => _value} ->
-        map
-
-      %{} ->
-        put(map, key, value)
-
-      other ->
-        :erlang.error({:badmap, other})
+    case has_key?(map, key) do
+      true  -> map
+      false -> put(map, key, value)
    end
  end

-  @doc false
-  @deprecated "Use Map.fetch/2 + Map.put/3 instead"
-  def replace(map, key, value) do
-    case map do
-      %{^key => _value} ->
-        put(map, key, value)
-
-      %{} ->
-        map
-
-      other ->
-        :erlang.error({:badmap, other})
-    end
-  end
-
-  @doc """
-  Alters the value stored under `key` to `value`, but only
-  if the entry `key` already exists in `map`.
-
-  If `key` is not present in `map`, a `KeyError` exception is raised.
-
-  Inlined by the compiler.
-
-  ## Examples
-
-      iex> Map.replace!(%{a: 1, b: 2}, :a, 3)
-      %{a: 3, b: 2}
-
-      iex> Map.replace!(%{a: 1}, :b, 2)
-      ** (KeyError) key :b not found in: %{a: 1}
-
-  """
-  @doc since: "1.5.0"
-  @spec replace!(map, key, value) :: map
-  def replace!(map, key, value) do
-    :maps.update(key, value, map)
-  end
-
  @doc """
  Evaluates `fun` and puts the result under `key`
-  in `map` unless `key` is already present.
+  in map unless `key` is already present.

-  This function is useful in case you want to compute the value to put under
-  `key` only if `key` is not already present (e.g., the value is expensive to
-  calculate or generally difficult to setup and teardown again).
+  This is useful if the value is very expensive to calculate or
+  generally difficult to setup and teardown again.

  ## Examples

@@ -354,23 +193,15 @@ defmodule Map do
  """
  @spec put_new_lazy(map, key, (() -> value)) :: map
  def put_new_lazy(map, key, fun) when is_function(fun, 0) do
-    case map do
-      %{^key => _value} ->
-        map
-
-      %{} ->
-        put(map, key, fun.())
-
-      other ->
-        :erlang.error({:badmap, other})
+    case has_key?(map, key) do
+      true  -> map
+      false -> put(map, key, fun.())
    end
  end

  @doc """
-  Returns a new map with all the key-value pairs in `map` where the key
-  is in `keys`.
-
-  If `keys` contains keys that are not in `map`, they're simply ignored.
+  Takes all entries corresponding to the given keys and
+  returns them in a new map.

  ## Examples

@@ -378,39 +209,21 @@ defmodule Map do
      %{a: 1, c: 3}

  """
-  @spec take(map, Enumerable.t()) :: map
-  def take(map, keys)
-
-  def take(map, keys) when is_map(map) do
-    keys
-    |> Enum.to_list()
-    |> take(map, [])
-  end
-
-  def take(non_map, _keys) do
-    :erlang.error({:badmap, non_map})
-  end
-
-  defp take([], _map, acc) do
-    :maps.from_list(acc)
-  end
-
-  defp take([key | rest], map, acc) do
-    acc =
-      case map do
-        %{^key => value} -> [{key, value} | acc]
-        %{} -> acc
+  @spec take(map, [key]) :: map
+  def take(map, keys) do
+    Enum.reduce(keys, new, fn key, acc ->
+      case fetch(map, key) do
+        {:ok, value} -> put(acc, key, value)
+        :error -> acc
      end
-
-    take(rest, map, acc)
+    end)
  end

  @doc """
-  Gets the value for a specific `key` in `map`.
+  Gets the value for a specific `key`.

-  If `key` is present in `map` with value `value`, then `value` is
-  returned. Otherwise, `default` is returned (which is `nil` unless
-  specified otherwise).
+  If `key` does not exist, return the default value
+  (`nil` if no default value).

  ## Examples

@@ -424,25 +237,19 @@ defmodule Map do
      3

  """
+  @spec get(map, key) :: value
  @spec get(map, key, value) :: value
  def get(map, key, default \\ nil) do
-    case map do
-      %{^key => value} ->
-        value
-
-      %{} ->
-        default
-
-      other ->
-        :erlang.error({:badmap, other}, [map, key, default])
+    case fetch(map, key) do
+      {:ok, value} -> value
+      :error -> default
    end
  end

  @doc """
-  Gets the value for a specific `key` in `map`.
+  Gets the value for a specific `key`.

-  If `key` is present in `map` with value `value`, then `value` is
-  returned. Otherwise, `fun` is evaluated and its result is returned.
+  If `key` does not exist, lazily evaluates `fun` and returns its result.

  This is useful if the default value is very expensive to calculate or
  generally difficult to setup and teardown again.
@@ -462,22 +269,14 @@ defmodule Map do
  """
  @spec get_lazy(map, key, (() -> value)) :: value
  def get_lazy(map, key, fun) when is_function(fun, 0) do
-    case map do
-      %{^key => value} ->
-        value
-
-      %{} ->
-        fun.()
-
-      other ->
-        :erlang.error({:badmap, other}, [map, key, fun])
+    case fetch(map, key) do
+      {:ok, value} -> value
+      :error -> fun.()
    end
  end

  @doc """
-  Puts the given `value` under `key` in `map`.
-
-  Inlined by the compiler.
+  Puts the given `value` under `key`.

  ## Examples

@@ -488,16 +287,14 @@ defmodule Map do

  """
  @spec put(map, key, value) :: map
-  def put(map, key, value) do
-    :maps.put(key, value, map)
+  def put(map, key, val) do
+    :maps.put(key, val, map)
  end

  @doc """
-  Deletes the entry in `map` for a specific `key`.
+  Deletes the entries in the map for a specific `key`.

-  If the `key` does not exist, returns `map` unchanged.
-
-  Inlined by the compiler.
+  If the `key` does not exist, returns the map unchanged.

  ## Examples

@@ -513,15 +310,7 @@ defmodule Map do
  @doc """
  Merges two maps into one.

-  All keys in `map2` will be added to `map1`, overriding any existing one
-  (i.e., the keys in `map2` "have precedence" over the ones in `map1`).
-
-  If you have a struct and you would like to merge a set of keys into the
-  struct, do not use this function, as it would merge all keys on the right
-  side into the struct, even if the key is not part of the struct. Instead,
-  use `Kernel.struct/2`.
-
-  Inlined by the compiler.
+  All keys in `map2` will be added to `map1`, overriding any existing one.

  ## Examples

@@ -533,13 +322,10 @@ defmodule Map do
  defdelegate merge(map1, map2), to: :maps

  @doc """
-  Merges two maps into one, resolving conflicts through the given `fun`.
+  Merges two maps into one.

-  All keys in `map2` will be added to `map1`. The given function will be invoked
-  when there are duplicate keys; its arguments are `key` (the duplicate key),
-  `value1` (the value of `key` in `map1`), and `value2` (the value of `key` in
-  `map2`). The value returned by `fun` is used as the value under `key` in
-  the resulting map.
+  All keys in `map2` will be added to `map1`. The given function will
+  be invoked with the key, value1 and value2 to solve conflicts.

  ## Examples

@@ -550,29 +336,16 @@ defmodule Map do

  """
  @spec merge(map, map, (key, value, value -> value)) :: map
-  def merge(map1, map2, fun) when is_function(fun, 3) do
-    if map_size(map1) > map_size(map2) do
-      folder = fn key, val2, acc ->
-        update(acc, key, val2, fn val1 -> fun.(key, val1, val2) end)
-      end
-
-      :maps.fold(folder, map1, map2)
-    else
-      folder = fn key, val2, acc ->
-        update(acc, key, val2, fn val1 -> fun.(key, val2, val1) end)
-      end
-
-      :maps.fold(folder, map2, map1)
-    end
+  def merge(map1, map2, callback) do
+    :maps.fold fn k, v2, acc ->
+      update(acc, k, v2, fn(v1) -> callback.(k, v1, v2) end)
+    end, map1, map2
  end

  @doc """
  Updates the `key` in `map` with the given function.

-  If `key` is present in `map` with value `value`, `fun` is invoked with
-  argument `value` and its result is used as the new value of `key`. If `key` is
-  not present in `map`, `initial` is inserted as the value of `key`. The initial
-  value will not be passed through the update function.
+  If the `key` does not exist, inserts the given `initial` value.

  ## Examples

@@ -583,25 +356,17 @@ defmodule Map do

  """
  @spec update(map, key, value, (value -> value)) :: map
-  def update(map, key, initial, fun) when is_function(fun, 1) do
-    case map do
-      %{^key => value} ->
+  def update(map, key, initial, fun) do
+    case fetch(map, key) do
+      {:ok, value} ->
        put(map, key, fun.(value))
-
-      %{} ->
+      :error ->
        put(map, key, initial)
-
-      other ->
-        :erlang.error({:badmap, other}, [map, key, initial, fun])
    end
  end

  @doc """
-  Returns and removes the value associated with `key` in `map`.
-
-  If `key` is present in `map` with value `value`, `{value, new_map}` is
-  returned where `new_map` is the result of removing `key` from `map`. If `key`
-  is not present in `map`, `{default, map}` is returned.
+  Returns and removes all values associated with `key` in the `map`.

  ## Examples

@@ -615,19 +380,14 @@ defmodule Map do
  """
  @spec pop(map, key, value) :: {value, map}
  def pop(map, key, default \\ nil) do
-    case :maps.take(key, map) do
-      {_, _} = tuple -> tuple
+    case fetch(map, key) do
+      {:ok, value} -> {value, delete(map, key)}
      :error -> {default, map}
    end
  end

  @doc """
-  Lazily returns and removes the value associated with `key` in `map`.
-
-  If `key` is present in `map` with value `value`, `{value, new_map}` is
-  returned where `new_map` is the result of removing `key` from `map`. If `key`
-  is not present in `map`, `{fun_result, map}` is returned, where `fun_result`
-  is the result of applying `fun`.
+  Lazily returns and removes all values associated with `key` in the `map`.

  This is useful if the default value is very expensive to calculate or
  generally difficult to setup and teardown again.
@@ -647,22 +407,14 @@ defmodule Map do
  """
  @spec pop_lazy(map, key, (() -> value)) :: {value, map}
  def pop_lazy(map, key, fun) when is_function(fun, 0) do
-    case map do
-      %{^key => value} ->
-        {value, delete(map, key)}
-
-      %{} ->
-        {fun.(), map}
-
-      other ->
-        :erlang.error({:badmap, other}, [map, key, fun])
+    case fetch(map, key) do
+      {:ok, value} -> {value, delete(map, key)}
+      :error -> {fun.(), map}
    end
  end

  @doc """
-  Drops the given `keys` from `map`.
-
-  If `keys` contains keys that are not in `map`, they're simply ignored.
+  Drops the given keys from the map.

  ## Examples

@@ -670,32 +422,18 @@ defmodule Map do
      %{a: 1, c: 3}

  """
-  @spec drop(map, Enumerable.t()) :: map
-  def drop(map, keys)
-
-  def drop(map, keys) when is_map(map) do
-    keys
-    |> Enum.to_list()
-    |> drop_list(map)
-  end
-
-  def drop(non_map, keys) do
-    :erlang.error({:badmap, non_map}, [non_map, keys])
-  end
-
-  defp drop_list([], acc), do: acc
-
-  defp drop_list([key | rest], acc) do
-    drop_list(rest, delete(acc, key))
+  @spec drop(map, [key]) :: map
+  def drop(map, keys) do
+    Enum.reduce(keys, map, &delete(&2, &1))
  end

  @doc """
-  Takes all entries corresponding to the given `keys` in `map` and extracts
-  them into a separate map.
+  Takes all entries corresponding to the given keys and extracts them into a
+  separate map.

  Returns a tuple with the new map and the old map with removed keys.

-  Keys for which there are no entries in `map` are ignored.
+  Keys for which there are no entires in the map are ignored.

  ## Examples

@@ -703,39 +441,22 @@ defmodule Map do
      {%{a: 1, c: 3}, %{b: 2}}

  """
-  @spec split(map, Enumerable.t()) :: {map, map}
-  def split(map, keys)
-
-  def split(map, keys) when is_map(map) do
-    keys
-    |> Enum.to_list()
-    |> split([], map)
-  end
-
-  def split(non_map, keys) do
-    :erlang.error({:badmap, non_map}, [non_map, keys])
-  end
-
-  defp split([], included, excluded) do
-    {:maps.from_list(included), excluded}
-  end
-
-  defp split([key | rest], included, excluded) do
-    case excluded do
-      %{^key => value} ->
-        split(rest, [{key, value} | included], delete(excluded, key))
-
-      _other ->
-        split(rest, included, excluded)
-    end
+  @spec split(map, [key]) :: {map, map}
+  def split(map, keys) do
+    Enum.reduce(keys, {new, map}, fn key, {inc, exc} = acc ->
+      case fetch(exc, key) do
+        {:ok, value} ->
+          {put(inc, key, value), delete(exc, key)}
+        :error ->
+          acc
+      end
+    end)
  end

  @doc """
-  Updates `key` with the given function.
+  Updates the `key` with the given function.

-  If `key` is present in `map` with value `value`, `fun` is invoked with
-  argument `value` and its result is used as the new value of `key`. If `key` is
-  not present in `map`, a `KeyError` exception is raised.
+  If the `key` does not exist, raises `KeyError`.

  ## Examples

@@ -743,27 +464,31 @@ defmodule Map do
      %{a: 2}

      iex> Map.update!(%{a: 1}, :b, &(&1 * 2))
-      ** (KeyError) key :b not found in: %{a: 1}
+      ** (KeyError) key :b not found

  """
-  @spec update!(map, key, (value -> value)) :: map
-  def update!(map, key, fun) when is_function(fun, 1) do
-    value = fetch!(map, key)
-    put(map, key, fun.(value))
+  @spec update!(map, key, (value -> value)) :: map | no_return
+  def update!(%{} = map, key, fun) do
+    case fetch(map, key) do
+      {:ok, value} ->
+        put(map, key, fun.(value))
+      :error ->
+        :erlang.error({:badkey, key})
+    end
  end

+  def update!(map, _key, _fun), do: :erlang.error({:badmap, map})
+
  @doc """
  Gets the value from `key` and updates it, all in one pass.

-  `fun` is called with the current value under `key` in `map` (or `nil` if `key`
-  is not present in `map`) and must return a two-element tuple: the "get" value
-  (the retrieved value, which can be operated on before being returned) and the
-  new value to be stored under `key` in the resulting new map. `fun` may also
-  return `:pop`, which means the current value shall be removed from `map` and
-  returned (making this function behave like `Map.pop(map, key)`).
+  This `fun` argument receives the value of `key` (or `nil` if `key`
+  is not present) and must return a two-elements tuple: the "get" value (the
+  retrieved value, which can be operated on before being returned) and the new
+  value to be stored under `key`.

-  The returned value is a tuple with the "get" value returned by
-  `fun` and a new map with the updated value under `key`.
+  The returned value is a tuple with the "get" value returned by `fun` and a
+  new map with the updated value under `key`.

  ## Examples

@@ -777,38 +502,34 @@ defmodule Map do
      ...> end)
      {nil, %{b: "new value!", a: 1}}

-      iex> Map.get_and_update(%{a: 1}, :a, fn _ -> :pop end)
-      {1, %{}}
-
-      iex> Map.get_and_update(%{a: 1}, :b, fn _ -> :pop end)
-      {nil, %{a: 1}}
-
  """
-  @spec get_and_update(map, key, (value -> {get, value} | :pop)) :: {get, map} when get: term
-  def get_and_update(map, key, fun) when is_function(fun, 1) do
-    current = get(map, key)
-
-    case fun.(current) do
-      {get, update} ->
-        {get, put(map, key, update)}
-
-      :pop ->
-        {current, delete(map, key)}
-
-      other ->
-        raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
+  @spec get_and_update(map, key, (value -> {get, value})) :: {get, map} when get: term
+  def get_and_update(%{} = map, key, fun) do
+    current_value = case :maps.find(key, map) do
+      {:ok, value} -> value
+      :error -> nil
    end
+
+    {get, update} = fun.(current_value)
+    {get, :maps.put(key, update, map)}
  end

+  def get_and_update(map, _key, _fun), do: :erlang.error({:badmap, map})
+
  @doc """
  Gets the value from `key` and updates it. Raises if there is no `key`.

-  Behaves exactly like `get_and_update/3`, but raises a `KeyError` exception if
-  `key` is not present in `map`.
+  This `fun` argument receives the value of `key` and must return a
+  two-elements tuple: the "get" value (the retrieved value, which can be
+  operated on before being returned) and the new value to be stored under
+  `key`.
+
+  The returned value is a tuple with the "get" value returned by `fun` and a
+  new map with the updated value under `key`.

  ## Examples

-      iex> Map.get_and_update!(%{a: 1}, :a, fn current_value ->
+      iex> Map.get_and_update!(%{a: 1}, :a, fn(current_value) ->
      ...>   {current_value, "new value!"}
      ...> end)
      {1, %{a: "new value!"}}
@@ -816,37 +537,27 @@ defmodule Map do
      iex> Map.get_and_update!(%{a: 1}, :b, fn current_value ->
      ...>   {current_value, "new value!"}
      ...> end)
-      ** (KeyError) key :b not found in: %{a: 1}
-
-      iex> Map.get_and_update!(%{a: 1}, :a, fn _ ->
-      ...>   :pop
-      ...> end)
-      {1, %{}}
+      ** (KeyError) key :b not found

  """
-  @spec get_and_update!(map, key, (value -> {get, value} | :pop)) :: {get, map} | no_return
-        when get: term
-  def get_and_update!(map, key, fun) when is_function(fun, 1) do
-    value = fetch!(map, key)
-
-    case fun.(value) do
-      {get, update} ->
-        {get, put(map, key, update)}
-
-      :pop ->
-        {value, delete(map, key)}
-
-      other ->
-        raise "the given function must return a two-element tuple or :pop, got: #{inspect(other)}"
+  @spec get_and_update!(map, key, (value -> {get, value})) :: {get, map} | no_return when get: term
+  def get_and_update!(%{} = map, key, fun) do
+    case :maps.find(key, map) do
+      {:ok, value} ->
+        {get, update} = fun.(value)
+        {get, :maps.put(key, update, map)}
+      :error ->
+        :erlang.error({:badkey, key})
    end
  end

+  def get_and_update!(map, _key, _fun), do: :erlang.error({:badmap, map})
+
  @doc """
-  Converts a `struct` to map.
+  Converts a struct to map.

  It accepts the struct module or a struct itself and
-  simply removes the `__struct__` field from the given struct
-  or from a new struct generated from the given module.
+  simply removes the `__struct__` field from the struct.

  ## Example

@@ -863,11 +574,11 @@ defmodule Map do
  """
  @spec from_struct(atom | struct) :: map
  def from_struct(struct) when is_atom(struct) do
-    delete(struct.__struct__(), :__struct__)
+    :maps.remove(:__struct__, struct.__struct__)
  end

-  def from_struct(%_{} = struct) do
-    delete(struct, :__struct__)
+  def from_struct(%{__struct__: _} = struct) do
+    :maps.remove(:__struct__, struct)
  end

  @doc """
@@ -885,15 +596,11 @@ defmodule Map do

  """
  @spec equal?(map, map) :: boolean
-  def equal?(map1, map2)
-
  def equal?(%{} = map1, %{} = map2), do: map1 === map2
-  def equal?(%{} = map1, map2), do: :erlang.error({:badmap, map2}, [map1, map2])
-  def equal?(term, other), do: :erlang.error({:badmap, term}, [term, other])

+  # TODO: Deprecate by 1.3
+  # TODO: Remove by 1.4
  @doc false
-  # TODO: Remove on 2.0
-  @deprecated "Use Kernel.map_size/1 instead"
  def size(map) do
    map_size(map)
  end
@@ -1,55 +1,24 @@
 defmodule MapSet do
  @moduledoc """
-  Functions that work on sets.
+  A set of functions for working with sets.

-  `MapSet` is the "go to" set data structure in Elixir. A set can be constructed
-  using `MapSet.new/0`:
-
-      iex> MapSet.new()
-      #MapSet<[]>
-
-  A set can contain any kind of elements, and elements in a set don't have to be
-  of the same type. By definition, sets can't contain duplicate elements: when
-  inserting an element in a set where it's already present, the insertion is
-  simply a no-op.
-
-      iex> map_set = MapSet.new()
-      iex> MapSet.put(map_set, "foo")
-      #MapSet<["foo"]>
-      iex> map_set |> MapSet.put("foo") |> MapSet.put("foo")
-      #MapSet<["foo"]>
-
-  A `MapSet` is represented internally using the `%MapSet{}` struct. This struct
-  can be used whenever there's a need to pattern match on something being a `MapSet`:
-
-      iex> match?(%MapSet{}, MapSet.new())
-      true
-
-  Note that, however, the struct fields are private and must not be accessed
-  directly; use the functions in this module to perform operations on sets.
-
-  `MapSet`s can also be constructed starting from other collection-type data
-  structures: for example, see `MapSet.new/1` or `Enum.into/2`.
+  The `MapSet` is represented internally as a struct,
+  therefore `%MapSet{}` can be used whenever there is a
+  need to match on any `MapSet`. Note though the struct
+  fields are private and must not be accessed directly.
+  Instead, use the functions in this module.
  """

-  # MapSets have an underlying Map. MapSet elements are keys of said map,
-  # and this empty list is their associated dummy value.
-  @dummy_value []
-
+  @opaque t :: %__MODULE__{map: map}
  @type value :: term
-
-  @opaque t(value) :: %__MODULE__{map: %{optional(value) => []}}
-  @type t :: t(term)
-
-  # TODO: Remove version key on Elixir 2.0
-  defstruct map: %{}, version: 2
+  defstruct map: %{}

  @doc """
  Returns a new set.

  ## Examples

-      iex> MapSet.new()
+      iex> MapSet.new
      #MapSet<[]>

  """
@@ -67,22 +36,13 @@ defmodule MapSet do
      #MapSet<[1, 2, 3]>

  """
-  @spec new(Enum.t()) :: t
-  def new(enumerable)
-
-  def new(%__MODULE__{} = map_set), do: map_set
-
+  @spec new(Enum.t) :: t
  def new(enumerable) do
-    map =
-      enumerable
-      |> Enum.to_list()
-      |> new_from_list([])
-
-    %MapSet{map: map}
+    Enum.reduce(enumerable, %MapSet{}, &put(&2, &1))
  end

  @doc """
-  Creates a set from an enumerable via the transformation function.
+  Creates a mapset from an enumerable via the transformation function.

  ## Examples

@@ -90,53 +50,32 @@ defmodule MapSet do
      #MapSet<[2, 4]>

  """
-  @spec new(Enum.t(), (term -> val)) :: t(val) when val: value
-  def new(enumerable, transform) when is_function(transform, 1) do
-    map =
-      enumerable
-      |> Enum.to_list()
-      |> new_from_list_transform(transform, [])
-
-    %MapSet{map: map}
-  end
-
-  defp new_from_list([], acc) do
-    :maps.from_list(acc)
-  end
-
-  defp new_from_list([item | rest], acc) do
-    new_from_list(rest, [{item, @dummy_value} | acc])
-  end
-
-  defp new_from_list_transform([], _fun, acc) do
-    :maps.from_list(acc)
-  end
-
-  defp new_from_list_transform([item | rest], fun, acc) do
-    new_from_list_transform(rest, fun, [{fun.(item), @dummy_value} | acc])
+  @spec new(Enum.t, (term -> term)) :: t
+  def new(enumerable, transform) do
+    Enum.reduce(enumerable, %MapSet{}, &put(&2, transform.(&1)))
  end

  @doc """
-  Deletes `value` from `map_set`.
+  Deletes `value` from `set`.

-  Returns a new set which is a copy of `map_set` but without `value`.
+  Returns a new set which is a copy of `set` but without `value`.

  ## Examples

-      iex> map_set = MapSet.new([1, 2, 3])
-      iex> MapSet.delete(map_set, 4)
+      iex> set = MapSet.new([1, 2, 3])
+      iex> MapSet.delete(set, 4)
      #MapSet<[1, 2, 3]>
-      iex> MapSet.delete(map_set, 2)
+      iex> MapSet.delete(set, 2)
      #MapSet<[1, 3]>

  """
-  @spec delete(t(val1), val2) :: t(val1) when val1: value, val2: value
-  def delete(%MapSet{map: map} = map_set, value) do
-    %{map_set | map: Map.delete(map, value)}
+  @spec delete(t, value) :: t
+  def delete(%MapSet{map: map} = set, term) do
+    %{set | map: Map.delete(map, term)}
  end

  @doc """
-  Returns a set that is `map_set1` without the members of `map_set2`.
+  Returns a set that is `set1` without the members of `set2`.

  ## Examples

@@ -144,40 +83,16 @@ defmodule MapSet do
      #MapSet<[1]>

  """
-  @spec difference(t(val1), t(val2)) :: t(val1) when val1: value, val2: value
-  def difference(map_set1, map_set2)
-
-  # If the first set is less than twice the size of the second map,
-  # it is fastest to re-accumulate items in the first set that are not
-  # present in the second set.
-  def difference(%MapSet{map: map1}, %MapSet{map: map2})
-      when map_size(map1) < map_size(map2) * 2 do
-    map =
-      map1
-      |> Map.keys()
-      |> filter_not_in(map2, [])
-
+  @spec difference(t, t) :: t
+  def difference(%MapSet{map: map1}, %MapSet{map: map2}) do
+    map = :maps.fold(fn value, _, acc ->
+      Map.delete(acc, value)
+    end, map1, map2)
    %MapSet{map: map}
  end

-  # If the second set is less than half the size of the first set, it's fastest
-  # to simply iterate through each item in the second set, deleting them from
-  # the first set.
-  def difference(%MapSet{map: map1} = map_set, %MapSet{map: map2}) do
-    %{map_set | map: Map.drop(map1, Map.keys(map2))}
-  end
-
-  defp filter_not_in([], _map2, acc), do: :maps.from_list(acc)
-
-  defp filter_not_in([key | rest], map2, acc) do
-    case map2 do
-      %{^key => _} -> filter_not_in(rest, map2, acc)
-      _ -> filter_not_in(rest, map2, [{key, @dummy_value} | acc])
-    end
-  end
-
  @doc """
-  Checks if `map_set1` and `map_set2` have no members in common.
+  Checks if `set1` and `set2` have no members in common.

  ## Examples

@@ -189,28 +104,22 @@ defmodule MapSet do
  """
  @spec disjoint?(t, t) :: boolean
  def disjoint?(%MapSet{map: map1}, %MapSet{map: map2}) do
-    {map1, map2} = order_by_size(map1, map2)
-
-    map1
-    |> Map.keys()
-    |> none_in?(map2)
-  end
-
-  defp none_in?([], _) do
-    true
-  end
-
-  defp none_in?([key | rest], map2) do
-    case map2 do
-      %{^key => _} -> false
-      _ -> none_in?(rest, map2)
-    end
+    if map_size(map1) > map_size(map2), do: {map1, map2} = {map2, map1}
+    :maps.fold(fn value, _, _ ->
+      if Map.has_key?(map2, value) do
+        throw({:halt, false})
+      else
+        true
+      end
+    end, true, map1)
+  catch
+    {:halt, false} -> false
  end

  @doc """
  Checks if two sets are equal.

-  The comparison between elements must be done using `===/2`.
+  The comparison between elements must be done using `===`.

  ## Examples

@@ -221,18 +130,12 @@ defmodule MapSet do

  """
  @spec equal?(t, t) :: boolean
-  def equal?(%MapSet{map: map1, version: version}, %MapSet{map: map2, version: version}) do
+  def equal?(%MapSet{map: map1}, %MapSet{map: map2}) do
    Map.equal?(map1, map2)
  end

-  # Elixir v1.5 change the map representation, so on
-  # version mismatch we need to compare the keys directly.
-  def equal?(%MapSet{map: map1}, %MapSet{map: map2}) do
-    map_size(map1) == map_size(map2) and map_subset?(Map.keys(map1), map2)
-  end
-
  @doc """
-  Returns a set containing only members that `map_set1` and `map_set2` have in common.
+  Returns a set containing only members that `set1` and `set2` have in common.

  ## Examples

@@ -243,14 +146,21 @@ defmodule MapSet do
      #MapSet<[]>

  """
-  @spec intersection(t(val), t(val)) :: t(val) when val: value
-  def intersection(%MapSet{map: map1} = map_set, %MapSet{map: map2}) do
-    {map1, map2} = order_by_size(map1, map2)
-    %{map_set | map: Map.take(map2, Map.keys(map1))}
+  @spec intersection(t, t) :: t
+  def intersection(%MapSet{map: map1}, %MapSet{map: map2}) do
+    if map_size(map1) > map_size(map2), do: {map1, map2} = {map2, map1}
+    map = :maps.fold(fn value, _, acc ->
+      if Map.has_key?(map2, value) do
+        Map.put(acc, value, true)
+      else
+        acc
+      end
+    end, %{}, map1)
+    %MapSet{map: map}
  end

  @doc """
-  Checks if `map_set` contains `value`.
+  Checks if `set` contains `value`.

  ## Examples

@@ -262,11 +172,11 @@ defmodule MapSet do
  """
  @spec member?(t, value) :: boolean
  def member?(%MapSet{map: map}, value) do
-    match?(%{^value => _}, map)
+    Map.has_key?(map, value)
  end

  @doc """
-  Inserts `value` into `map_set` if `map_set` doesn't already contain it.
+  Inserts `value` into `set` if `set` doesn't already contain it.

  ## Examples

@@ -276,13 +186,13 @@ defmodule MapSet do
      #MapSet<[1, 2, 3, 4]>

  """
-  @spec put(t(val), new_val) :: t(val | new_val) when val: value, new_val: value
-  def put(%MapSet{map: map} = map_set, value) do
-    %{map_set | map: Map.put(map, value, @dummy_value)}
+  @spec put(t, value) :: t
+  def put(%MapSet{map: map} = set, value) do
+    %{set | map: Map.put(map, value, true)}
  end

  @doc """
-  Returns the number of elements in `map_set`.
+  Returns the number of elements in `set`.

  ## Examples

@@ -296,9 +206,9 @@ defmodule MapSet do
  end

  @doc """
-  Checks if `map_set1`'s members are all contained in `map_set2`.
+  Checks if `set1`'s members are all contained in `set2`.

-  This function checks if `map_set1` is a subset of `map_set2`.
+  This function checks if `set1` is a subset of `set2`.

  ## Examples

@@ -311,22 +221,22 @@ defmodule MapSet do
  @spec subset?(t, t) :: boolean
  def subset?(%MapSet{map: map1}, %MapSet{map: map2}) do
    if map_size(map1) <= map_size(map2) do
-      map1
-      |> Map.keys()
-      |> map_subset?(map2)
+      :maps.fold(fn value, _, _ ->
+        if Map.has_key?(map2, value) do
+          true
+        else
+          throw({:halt, false})
+        end
+      end, true, map1)
    else
      false
    end
-  end
-
-  defp map_subset?([], _), do: true
-
-  defp map_subset?([key | rest], map2) do
-    match?(%{^key => _}, map2) and map_subset?(rest, map2)
+  catch
+    {:halt, false} -> false
  end

  @doc """
-  Converts `map_set` to a list.
+  Converts `set` to a list.

  ## Examples

@@ -334,13 +244,13 @@ defmodule MapSet do
      [1, 2, 3]

  """
-  @spec to_list(t(val)) :: [val] when val: value
+  @spec to_list(t) :: list
  def to_list(%MapSet{map: map}) do
    Map.keys(map)
  end

  @doc """
-  Returns a set containing all members of `map_set1` and `map_set2`.
+  Returns a set containing all members of `set1` and `set2`.

  ## Examples

@@ -348,57 +258,32 @@ defmodule MapSet do
      #MapSet<[1, 2, 3, 4]>

  """
-  @spec union(t(val1), t(val2)) :: t(val1 | val2) when val1: value, val2: value
-  def union(map_set1, map_set2)
-
-  def union(%MapSet{map: map1, version: version} = map_set, %MapSet{map: map2, version: version}) do
-    %{map_set | map: Map.merge(map1, map2)}
-  end
-
+  @spec union(t, t) :: t
  def union(%MapSet{map: map1}, %MapSet{map: map2}) do
-    map = new_from_list(Map.keys(map1) ++ Map.keys(map2), [])
-    %MapSet{map: map}
+    %MapSet{map: Map.merge(map1, map2)}
  end

-  @compile {:inline, [order_by_size: 2]}
-  defp order_by_size(map1, map2) when map_size(map1) > map_size(map2), do: {map2, map1}
-  defp order_by_size(map1, map2), do: {map1, map2}
-
  defimpl Enumerable do
-    def count(map_set) do
-      {:ok, MapSet.size(map_set)}
-    end
-
-    def member?(map_set, val) do
-      {:ok, MapSet.member?(map_set, val)}
-    end
-
-    def slice(map_set) do
-      {:ok, MapSet.size(map_set), &Enumerable.List.slice(MapSet.to_list(map_set), &1, &2)}
-    end
-
-    def reduce(map_set, acc, fun) do
-      Enumerable.List.reduce(MapSet.to_list(map_set), acc, fun)
-    end
+    def reduce(set, acc, fun), do: Enumerable.List.reduce(MapSet.to_list(set), acc, fun)
+    def member?(set, val),     do: {:ok, MapSet.member?(set, val)}
+    def count(set),            do: {:ok, MapSet.size(set)}
  end

  defimpl Collectable do
-    def into(map_set) do
-      fun = fn
-        list, {:cont, x} -> [{x, []} | list]
-        list, :done -> %{map_set | map: Map.merge(map_set.map, Map.new(list))}
+    def into(original) do
+      {original, fn
+        set, {:cont, x} -> MapSet.put(set, x)
+        set, :done -> set
        _, :halt -> :ok
-      end
-
-      {[], fun}
+      end}
    end
  end

  defimpl Inspect do
    import Inspect.Algebra

-    def inspect(map_set, opts) do
-      concat(["#MapSet<", Inspect.List.inspect(MapSet.to_list(map_set), opts), ">"])
+    def inspect(set, opts) do
+      concat ["#MapSet<", Inspect.List.inspect(MapSet.to_list(set), opts), ">"]
    end
  end
 end
@@ -4,203 +4,357 @@
 #
 # ## Implementation
 #
-# The implementation uses ets to track all dependencies
-# resembling a graph. The keys and what they point to are:
+# The implementation uses the digraph module to track
+# all dependencies. The graph starts with one main vertex:
 #
-#   * `:reattach` points to `{name, arity}`
-#   * `{:local, {name, arity}}` points to `{name, arity}`
-#   * `{:import, {name, arity}}` points to `Module`
+# * `:local` - points to local functions
 #
-# This is built on top of the internal module tables.
+# We can also have the following vertices:
+#
+# * `Module` - a module that was invoked via an import
+# * `{name, arity}` - a local function/arity pair
+# * `{:import, name, arity}` - an invoked function/arity import
+#
+# Each of those vertices can associate to other vertices
+# as described below:
+#
+# * `Module`
+#   * in neighbours:  `{:import, name, arity}`
+#
+# * `{name, arity}`
+#   * in neighbours: `:local`, `{name, arity}`
+#   * out neighbours: `{:import, name, arity}`
+#
+# * `{:import, name, arity}`
+#   * in neighbours: `{name, arity}`
+#   * out neighbours: `Module`
+#
+# Note that since this is required for bootstrap, we can't use
+# any of the `GenServer` conveniences.
 defmodule Module.LocalsTracker do
  @moduledoc false

+  @timeout   30_000
+  @behaviour :gen_server
+
+  @type ref :: pid | module
+  @type name :: atom
+  @type name_arity :: {name, arity}
+
+  @type local :: {name, arity}
+  @type import :: {:import, name, arity}
+
+  # Public API
+
  @doc """
-  Adds and tracks defaults for a definition into the tracker.
+  Returns all imported modules that had the given
+  `{name, arity}` invoked.
  """
-  def add_defaults({_set, bag}, _kind, {name, arity} = pair, defaults) do
-    for i <- :lists.seq(arity - defaults, arity - 1) do
-      put_edge(bag, {:local, {name, i}}, pair)
-    end
-
-    :ok
+  @spec imports_with_dispatch(ref, name_arity) :: [module]
+  def imports_with_dispatch(ref, {name, arity}) do
+    d = :gen_server.call(to_pid(ref), :digraph, @timeout)
+    :digraph.out_neighbours(d, {:import, name, arity})
  end

  @doc """
-  Adds a local dispatch from-to the given target.
-  """
-  def add_local({_set, bag}, from, to) when is_tuple(from) and is_tuple(to) do
-    if from != to do
-      put_edge(bag, {:local, from}, to)
-    end
-
-    :ok
-  end
-
-  @doc """
-  Adds an import dispatch to the given target.
-  """
-  def add_import({set, _bag}, function, module, imported)
-      when is_tuple(function) and is_atom(module) do
-    put_edge(set, {:import, imported}, module)
-    :ok
-  end
-
-  @doc """
-  Yanks a local node. Returns its in and out vertices in a tuple.
-  """
-  def yank({_set, bag}, local) do
-    :lists.usort(take_out_neighbours(bag, {:local, local}))
-  end
-
-  @doc """
-  Reattach a previously yanked node.
-  """
-  def reattach({_set, bag}, tuple, _kind, function, out_neigh) do
-    for to <- out_neigh do
-      put_edge(bag, {:local, function}, to)
-    end
-
-    # Make a call from the old function to the new one
-    if function != tuple do
-      put_edge(bag, {:local, function}, tuple)
-    end
-
-    # Finally marked the new one as reattached
-    put_edge(bag, :reattach, tuple)
-    :ok
-  end
-
-  # Collecting all conflicting imports with the given functions
-  @doc false
-  def collect_imports_conflicts({set, _bag}, all_defined) do
-    for {pair, _, meta, _} <- all_defined, n = out_neighbour(set, {:import, pair}) do
-      {meta, {n, pair}}
-    end
-  end
-
-  @doc """
-  Collect all unused definitions based on the private
-  given, also accounting the expected number of default
-  clauses a private function have.
-  """
-  def collect_unused_locals({_set, bag}, all_defined, private) do
-    reachable =
-      Enum.reduce(all_defined, %{}, fn {pair, kind, _, _}, acc ->
-        if kind in [:def, :defmacro] do
-          reachable_from(bag, pair, acc)
-        else
-          acc
-        end
-      end)
-
-    reattached = :lists.usort(out_neighbours(bag, :reattach))
-    {unreachable(reachable, reattached, private), collect_warnings(reachable, private)}
-  end
-
-  defp unreachable(reachable, reattached, private) do
-    for {tuple, kind, _, _} <- private,
-        not reachable?(tuple, kind, reachable, reattached),
-        do: tuple
-  end
-
-  defp reachable?(tuple, :defmacrop, reachable, reattached) do
-    # All private micros are unreachable unless they have been
-    # reattached and they are reachable.
-    :lists.member(tuple, reattached) and Map.has_key?(reachable, tuple)
-  end
-
-  defp reachable?(tuple, :defp, reachable, _reattached) do
-    Map.has_key?(reachable, tuple)
-  end
-
-  defp collect_warnings(reachable, private) do
-    :lists.foldl(&collect_warnings(&1, &2, reachable), [], private)
-  end
-
-  defp collect_warnings({_, _, false, _}, acc, _reachable) do
-    acc
-  end
-
-  defp collect_warnings({tuple, kind, meta, 0}, acc, reachable) do
-    if Map.has_key?(reachable, tuple) do
-      acc
-    else
-      [{meta, {:unused_def, tuple, kind}} | acc]
-    end
-  end
-
-  defp collect_warnings({tuple, kind, meta, default}, acc, reachable) when default > 0 do
-    {name, arity} = tuple
-    min = arity - default
-    max = arity
-
-    case min_reachable_default(max, min, :none, name, reachable) do
-      :none -> [{meta, {:unused_def, tuple, kind}} | acc]
-      ^min -> acc
-      ^max -> [{meta, {:unused_args, tuple}} | acc]
-      diff -> [{meta, {:unused_args, tuple, diff}} | acc]
-    end
-  end
-
-  defp min_reachable_default(max, min, last, name, reachable) when max >= min do
-    case Map.has_key?(reachable, {name, max}) do
-      true -> min_reachable_default(max - 1, min, max, name, reachable)
-      false -> min_reachable_default(max - 1, min, last, name, reachable)
-    end
-  end
-
-  defp min_reachable_default(_max, _min, last, _name, _reachable) do
-    last
-  end
-
-  @doc """
-  Returns all local nodes reachable from `vertex`.
+  Returns all locals that are reachable.

  By default, all public functions are reachable.
  A private function is only reachable if it has
  a public function that it invokes directly.
  """
-  def reachable_from({_, bag}, local) do
-    bag
-    |> reachable_from(local, %{})
-    |> Map.keys()
+  @spec reachable(ref) :: [local]
+  def reachable(ref) do
+    reachable_from(:gen_server.call(to_pid(ref), :digraph, @timeout), :local)
  end

-  defp reachable_from(bag, local, vertices) do
-    vertices = Map.put(vertices, local, true)
+  defp reachable_from(d, starting) do
+    :sets.to_list(reduce_reachable(d, starting, :sets.new))
+  end

-    Enum.reduce(out_neighbours(bag, {:local, local}), vertices, fn {_, _} = local, acc ->
-      case acc do
-        %{^local => true} -> acc
-        _ -> reachable_from(bag, local, acc)
+  defp reduce_reachable(d, vertex, vertices) do
+    neighbours = :digraph.out_neighbours(d, vertex)
+    neighbours = (for {_, _} = t <- neighbours, do: t) |> :sets.from_list
+    remaining  = :sets.subtract(neighbours, vertices)
+    vertices   = :sets.union(neighbours, vertices)
+    :sets.fold(&reduce_reachable(d, &1, &2), vertices, remaining)
+  end
+
+  defp to_pid(pid) when is_pid(pid),  do: pid
+  defp to_pid(mod) when is_atom(mod) do
+    table = :elixir_module.data_table(mod)
+    [{_, val}] = :ets.lookup(table, {:elixir, :locals_tracker})
+    val
+  end
+
+  # Internal API
+
+  # Starts the tracker and returns its pid.
+  @doc false
+  def start_link do
+    :gen_server.start_link(__MODULE__, [], [])
+  end
+
+  # Adds a definition into the tracker. A public
+  # definition is connected with the :local node
+  # while a private one is left unreachable until
+  # a call is made to.
+  @doc false
+  def add_definition(pid, kind, tuple) when kind in [:def, :defp, :defmacro, :defmacrop] do
+    :gen_server.cast(pid, {:add_definition, kind, tuple})
+  end
+
+  # Adds and tracks defaults for a definition into the tracker.
+  @doc false
+  def add_defaults(pid, kind, tuple, defaults) when kind in [:def, :defp, :defmacro, :defmacrop] do
+    :gen_server.cast(pid, {:add_defaults, kind, tuple, defaults})
+  end
+
+  # Adds a local dispatch to the given target.
+  def add_local(pid, to) when is_tuple(to) do
+    :gen_server.cast(pid, {:add_local, :local, to})
+  end
+
+  # Adds a local dispatch from-to the given target.
+  @doc false
+  def add_local(pid, from, to) when is_tuple(from) and is_tuple(to) do
+    :gen_server.cast(pid, {:add_local, from, to})
+  end
+
+  # Adds a import dispatch to the given target.
+  @doc false
+  def add_import(pid, function, module, target) when is_atom(module) and is_tuple(target) do
+    :gen_server.cast(pid, {:add_import, function, module, target})
+  end
+
+  # Yanks a local node. Returns its in and out vertices in a tuple.
+  @doc false
+  def yank(pid, local) do
+    :gen_server.call(to_pid(pid), {:yank, local}, @timeout)
+  end
+
+  # Reattach a previously yanked node
+  @doc false
+  def reattach(pid, kind, tuple, neighbours) do
+    :gen_server.cast(to_pid(pid), {:reattach, kind, tuple, neighbours})
+  end
+
+  # Collecting all conflicting imports with the given functions
+  @doc false
+  def collect_imports_conflicts(pid, all_defined) do
+    d = :gen_server.call(pid, :digraph, @timeout)
+
+    for {name, arity} <- all_defined,
+        :digraph.in_neighbours(d, {:import, name, arity}) != [],
+        n = :digraph.out_neighbours(d, {:import, name, arity}),
+        n != [] do
+      {n, name, arity}
+    end
+  end
+
+  # Collect all unused definitions based on the private
+  # given also accounting the expected amount of default
+  # clauses a private function have.
+  @doc false
+  def collect_unused_locals(ref, private) do
+    d = :gen_server.call(to_pid(ref), :digraph, @timeout)
+    {unreachable(d, private), collect_warnings(d, private)}
+  end
+
+  defp unreachable(d, private) do
+    unreachable = for {tuple, _, _} <- private, do: tuple
+
+    private =
+      for {tuple, :defp, _} <- private do
+        neighbours = :digraph.in_neighbours(d, tuple)
+        neighbours = for {_, _} = t <- neighbours, do: t
+        {tuple, :sets.from_list(neighbours)}
      end
-    end)
+
+    reduce_unreachable(private, [], :sets.from_list(unreachable))
  end

-  ## Lightweight digraph implementation
-
-  defp put_edge(d, from, to) do
-    :ets.insert(d, {from, to})
-  end
-
-  defp out_neighbour(d, from) do
-    try do
-      :ets.lookup_element(d, from, 2)
-    catch
-      :error, :badarg -> nil
+  defp reduce_unreachable([{vertex, callers}|t], acc, unreachable) do
+    if :sets.is_subset(callers, unreachable) do
+      reduce_unreachable(t, [{vertex, callers}|acc], unreachable)
+    else
+      reduce_unreachable(acc ++ t, [], :sets.del_element(vertex, unreachable))
    end
  end

-  defp out_neighbours(d, from) do
-    try do
-      :ets.lookup_element(d, from, 2)
-    catch
-      :error, :badarg -> []
+  defp reduce_unreachable([], _acc, unreachable) do
+    :sets.to_list(unreachable)
+  end
+
+  defp collect_warnings(d, private) do
+    reachable = reachable_from(d, :local)
+    :lists.foldl(&collect_warnings(&1, &2, reachable), [], private)
+  end
+
+  defp collect_warnings({tuple, kind, 0}, acc, reachable) do
+    if :lists.member(tuple, reachable) do
+      acc
+    else
+      [{:unused_def, tuple, kind}|acc]
    end
  end

-  defp take_out_neighbours(d, from) do
-    Keyword.values(:ets.take(d, from))
+  defp collect_warnings({tuple, kind, default}, acc, reachable) when default > 0 do
+    {name, arity} = tuple
+    min = arity - default
+    max = arity
+
+    invoked = for {n, a} <- reachable, n == name, a in min..max, do: a
+
+    if invoked == [] do
+      [{:unused_def, tuple, kind}|acc]
+    else
+      case :lists.min(invoked) - min do
+        0 -> acc
+        ^default -> [{:unused_args, tuple}|acc]
+        unused_args -> [{:unused_args, tuple, unused_args}|acc]
+      end
+    end
+  end
+
+  @doc false
+  def cache_env(pid, env) do
+    :gen_server.call(pid, {:cache_env, env}, @timeout)
+  end
+
+  @doc false
+  def get_cached_env(pid, ref) do
+    :gen_server.call(pid, {:get_cached_env, ref}, @timeout)
+  end
+
+  # Stops the gen server
+  @doc false
+  def stop(pid) do
+    :gen_server.cast(pid, :stop)
+  end
+
+  # Callbacks
+
+  def init([]) do
+    d = :digraph.new([:protected])
+    :digraph.add_vertex(d, :local)
+    {:ok, {d, []}}
+  end
+
+  @doc false
+  def handle_call({:cache_env, env}, _from, {d, cache}) do
+    case cache do
+      [{i, ^env}|_] ->
+        {:reply, i, {d, cache}}
+      t ->
+        i = length(t)
+        {:reply, i, {d, [{i, env}|t]}}
+    end
+  end
+
+  def handle_call({:get_cached_env, ref}, _from, {_, cache} = state) do
+    {^ref, env} = :lists.keyfind(ref, 1, cache)
+    {:reply, env, state}
+  end
+
+  def handle_call({:yank, local}, _from, {d, _} = state) do
+    out_vertices = :digraph.out_neighbours(d, local)
+    :digraph.del_edges(d, :digraph.out_edges(d, local))
+    {:reply, {[], out_vertices}, state}
+  end
+
+  def handle_call(:digraph, _from, {d, _} = state) do
+    {:reply, d, state}
+  end
+
+  @doc false
+  def handle_info(_msg, state) do
+    {:noreply, state}
+  end
+
+  def handle_cast({:add_local, from, to}, {d, _} = state) do
+    handle_add_local(d, from, to)
+    {:noreply, state}
+  end
+
+  def handle_cast({:add_import, function, module, {name, arity}}, {d, _} = state) do
+    handle_import(d, function, module, name, arity)
+    {:noreply, state}
+  end
+
+  def handle_cast({:add_definition, kind, tuple}, {d, _} = state) do
+    handle_add_definition(d, kind, tuple)
+    {:noreply, state}
+  end
+
+  def handle_cast({:add_defaults, kind, {name, arity}, defaults}, {d, _} = state) do
+    for i <- :lists.seq(arity - defaults, arity - 1) do
+      handle_add_definition(d, kind, {name, i})
+      handle_add_local(d, {name, i}, {name, i + 1})
+    end
+    {:noreply, state}
+  end
+
+  def handle_cast({:reattach, _kind, tuple, {in_neigh, out_neigh}}, {d, _} = state) do
+    for from <- in_neigh do
+      :digraph.add_vertex(d, from)
+      replace_edge!(d, from, tuple)
+    end
+
+    for to <- out_neigh do
+      :digraph.add_vertex(d, to)
+      replace_edge!(d, tuple, to)
+    end
+
+    {:noreply, state}
+  end
+
+  def handle_cast(:stop, state) do
+    {:stop, :normal, state}
+  end
+
+  @doc false
+  def terminate(_reason, _state) do
+    :ok
+  end
+
+  @doc false
+  def code_change(_old, state, _extra) do
+    {:ok, state}
+  end
+
+  defp handle_import(d, function, module, name, arity) do
+    :digraph.add_vertex(d, module)
+
+    tuple = {:import, name, arity}
+    :digraph.add_vertex(d, tuple)
+    replace_edge!(d, tuple, module)
+
+    if function != nil do
+      replace_edge!(d, function, tuple)
+    end
+
+    :ok
+  end
+
+  defp handle_add_local(d, from, to) do
+    :digraph.add_vertex(d, to)
+    replace_edge!(d, from, to)
+  end
+
+  defp handle_add_definition(d, public, tuple) when public in [:def, :defmacro] do
+    :digraph.add_vertex(d, tuple)
+    replace_edge!(d, :local, tuple)
+  end
+
+  defp handle_add_definition(d, private, tuple) when private in [:defp, :defmacrop] do
+    :digraph.add_vertex(d, tuple)
+  end
+
+  defp replace_edge!(d, from, to) do
+    _ = unless :lists.member(to, :digraph.out_neighbours(d, from)) do
+      [:"$e"|_] = :digraph.add_edge(d, from, to)
+    end
+    :ok
  end
 end
@@ -16,7 +16,8 @@ defmodule Node do
  This functionality starts the `:net_kernel` and other
  related processes.
  """
-  @spec start(node, :longnames | :shortnames, non_neg_integer) :: {:ok, pid} | {:error, term}
+  @spec start(node, :longnames | :shortnames, non_neg_integer) ::
+             {:ok, pid} | {:error, term}
  def start(name, type \\ :longnames, tick_time \\ 15000) do
    :net_kernel.start([name, type, tick_time])
  end
@@ -59,8 +60,6 @@ defmodule Node do
  the local node.

  Same as `list(:visible)`.
-
-  Inlined by the compiler.
  """
  @spec list :: [t]
  def list do
@@ -73,11 +72,10 @@ defmodule Node do
  The result returned when the argument is a list, is the list of nodes
  satisfying the disjunction(s) of the list elements.

-  For more information, see `:erlang.nodes/1`.
-
-  Inlined by the compiler.
+  For more information, see
+  [`:erlang.nodes/1`](http://www.erlang.org/doc/man/erlang.html#nodes-1).
  """
-  @type state :: :visible | :hidden | :connected | :this | :known
+  @typep state :: :visible | :hidden | :connected | :this | :known
  @spec list(state | [state]) :: [t]
  def list(args) do
    :erlang.nodes(args)
@@ -89,9 +87,8 @@ defmodule Node do
  If `flag` is `true`, monitoring is turned on.
  If `flag` is `false`, monitoring is turned off.

-  For more information, see `:erlang.monitor_node/2`.
-
-  For monitoring status changes of all nodes, see `:net_kernel.monitor_nodes/3`.
+  For more information, see
+  [`:erlang.monitor_node/2`](http://www.erlang.org/doc/man/erlang.html#monitor_node-2).
  """
  @spec monitor(t, boolean) :: true
  def monitor(node, flag) do
@@ -102,9 +99,8 @@ defmodule Node do
  Behaves as `monitor/2` except that it allows an extra
  option to be given, namely `:allow_passive_connect`.

-  For more information, see `:erlang.monitor_node/3`.
-
-  For monitoring status changes of all nodes, see `:net_kernel.monitor_nodes/3`.
+  For more information, see
+  [`:erlang.monitor_node/3`](http://www.erlang.org/doc/man/erlang.html#monitor_node-3).
  """
  @spec monitor(t, boolean, [:allow_passive_connect]) :: true
  def monitor(node, flag, options) do
@@ -135,7 +131,8 @@ defmodule Node do
  protocols. Returns `true` if disconnection succeeds, otherwise `false`.
  If the local node is not alive, the function returns `:ignored`.

-  For more information, see `:erlang.disconnect_node/1`.
+  For more information, see
+  [`:erlang.disconnect_node/1`](http://www.erlang.org/doc/man/erlang.html#disconnect_node-1).
  """
  @spec disconnect(t) :: boolean | :ignored
  def disconnect(node) do
@@ -148,7 +145,8 @@ defmodule Node do
  Returns `true` if successful, `false` if not, and the atom
  `:ignored` if the local node is not alive.

-  For more information, see `:net_kernel.connect_node/1`.
+  For more information, see
+  [`:erlang.connect_node/1`](http://www.erlang.org/doc/man/net_kernel.html#connect_node-1).
  """
  @spec connect(t) :: boolean | :ignored
  def connect(node) do
@@ -156,10 +154,11 @@ defmodule Node do
  end

  @doc """
-  Returns the PID of a new process started by the application of `fun`
-  on `node`. If `node` does not exist, a useless PID is returned.
+  Returns the pid of a new process started by the application of `fun`
+  on `node`. If `node` does not exist, a useless pid is returned.

-  For the list of available options, see `:erlang.spawn/2`.
+  For the list of available options, see
+  [`:erlang.spawn/2`](http://www.erlang.org/doc/man/erlang.html#spawn-2).

  Inlined by the compiler.
  """
@@ -169,27 +168,29 @@ defmodule Node do
  end

  @doc """
-  Returns the PID of a new process started by the application of `fun`
+  Returns the pid of a new process started by the application of `fun`
  on `node`.

-  If `node` does not exist, a useless PID is returned.
+  If `node` does not exist, a useless pid is returned.

-  For the list of available options, see `:erlang.spawn_opt/3`.
+  For the list of available options, see
+  [`:erlang.spawn_opt/3`](http://www.erlang.org/doc/man/erlang.html#spawn_opt-3).

  Inlined by the compiler.
  """
-  @spec spawn(t, (() -> any), Process.spawn_opts()) :: pid | {pid, reference}
+  @spec spawn(t, (() -> any), Process.spawn_opts) :: pid | {pid, reference}
  def spawn(node, fun, opts) do
    :erlang.spawn_opt(node, fun, opts)
  end

  @doc """
-  Returns the PID of a new process started by the application of
+  Returns the pid of a new process started by the application of
  `module.function(args)` on `node`.

-  If `node` does not exist, a useless PID is returned.
+  If `node` does not exist, a useless pid is returned.

-  For the list of available options, see `:erlang.spawn/4`.
+  For the list of available options, see
+  [`:erlang.spawn/4`](http://www.erlang.org/doc/man/erlang.html#spawn-4).

  Inlined by the compiler.
  """
@@ -199,25 +200,26 @@ defmodule Node do
  end

  @doc """
-  Returns the PID of a new process started by the application of
+  Returns the pid of a new process started by the application of
  `module.function(args)` on `node`.

-  If `node` does not exist, a useless PID is returned.
+  If `node` does not exist, a useless pid is returned.

-  For the list of available options, see `:erlang.spawn/5`.
+  For the list of available options, see
+  [`:erlang.spawn/5`](http://www.erlang.org/doc/man/erlang.html#spawn_opt-5).

  Inlined by the compiler.
  """
-  @spec spawn(t, module, atom, [any], Process.spawn_opts()) :: pid | {pid, reference}
+  @spec spawn(t, module, atom, [any], Process.spawn_opts) :: pid | {pid, reference}
  def spawn(node, module, fun, args, opts) do
    :erlang.spawn_opt(node, module, fun, args, opts)
  end

  @doc """
-  Returns the PID of a new linked process started by the application of `fun` on `node`.
+  Returns the pid of a new linked process started by the application of `fun` on `node`.

  A link is created between the calling process and the new process, atomically.
-  If `node` does not exist, a useless PID is returned (and due to the link, an exit
+  If `node` does not exist, a useless pid is returned (and due to the link, an exit
  signal with exit reason `:noconnection` will be received).

  Inlined by the compiler.
@@ -228,11 +230,11 @@ defmodule Node do
  end

  @doc """
-  Returns the PID of a new linked process started by the application of
+  Returns the pid of a new linked process started by the application of
  `module.function(args)` on `node`.

  A link is created between the calling process and the new process, atomically.
-  If `node` does not exist, a useless PID is returned (and due to the link, an exit
+  If `node` does not exist, a useless pid is returned (and due to the link, an exit
  signal with exit reason `:noconnection` will be received).

  Inlined by the compiler.
@@ -250,7 +252,7 @@ defmodule Node do

  This function will raise `FunctionClauseError` if the given `node` is not alive.
  """
-  def set_cookie(node \\ Node.self(), cookie) when is_atom(cookie) do
+  def set_cookie(node \\ Node.self, cookie) when is_atom(cookie) do
    :erlang.set_cookie(node, cookie)
  end

@@ -3,164 +3,75 @@ defmodule OptionParser do
  This module contains functions to parse command line options.
  """

-  @type argv :: [String.t()]
-  @type parsed :: keyword
-  @type errors :: [{String.t(), String.t() | nil}]
-  @type options :: [switches: keyword, strict: keyword, aliases: keyword]
-
-  defmodule ParseError do
-    defexception [:message]
-  end
+  @type argv    :: [String.t]
+  @type parsed  :: Keyword.t
+  @type errors  :: [{String.t, String.t | nil}]
+  @type options :: [switches: Keyword.t, strict: Keyword.t, aliases: Keyword.t]

  @doc """
-  Parses `argv` into a keyword list.
+  Parses `argv` into a keywords list.

-  It returns a three-element tuple with the form `{parsed, args, invalid}`, where:
+  It returns a three-element tuple as follows:

-    * `parsed` is a keyword list of parsed switches with `{switch_name, value}`
-      tuples in it; `switch_name` is the atom representing the switch name while
-      `value` is the value for that switch parsed according to `opts` (see the
-      "Examples" section for more information)
-    * `args` is a list of the remaining arguments in `argv` as strings
-    * `invalid` is a list of invalid options as `{option_name, value}` where
-      `option_name` is the raw option and `value` is `nil` if the option wasn't
-      expected or the string value if the value didn't have the expected type for
-      the corresponding option
-
-  Elixir converts switches to underscored atoms, so `--source-path` becomes
-  `:source_path`. This is done to better suit Elixir conventions. However, this
-  means that switches can't contain underscores and switches that do contain
-  underscores are always returned in the list of invalid switches.
-
-  When parsing, it is common to list switches and their expected types:
-
-      iex> OptionParser.parse(["--debug"], strict: [debug: :boolean])
-      {[debug: true], [], []}
-
-      iex> OptionParser.parse(["--source", "lib"], strict: [source: :string])
-      {[source: "lib"], [], []}
-
-      iex> OptionParser.parse(["--source-path", "lib", "test/enum_test.exs", "--verbose"],
-      ...>                    strict: [source_path: :string, verbose: :boolean])
-      {[source_path: "lib", verbose: true], ["test/enum_test.exs"], []}
-
-  We will explore the valid switches and operation modes of option parser below.
-
-  ## Options
-
-  The following options are supported:
-
-    * `:switches` or `:strict` - see the "Switch definitions" section below
-    * `:allow_nonexistent_atoms` - see the "Parsing unknown switches" section below
-    * `:aliases` - see the "Aliases" section below
-
-  ## Switch definitions
-
-  Switches can be specified via one of two options:
-
-    * `:strict` - defines strict switches. Any switch in `argv` that is not
-      specified in the list is returned in the invalid options list.
-    * `:switches` - defines some switches and their types. This function
-      still attempts to parse switches that are not in this list.
-
-  Both these options accept a keyword list of `{name, type}` tuples where `name`
-  is an atom defining the name of the switch and `type` is an atom that
-  specifies the type for the value of this switch (see the "Types" section below
-  for the possible types and more information about type casting).
-
-  Note that you should only supply the `:switches` or the `:strict` option.
-  If you supply both, an `ArgumentError` exception will be raised.
-
-  ### Types
-
-  Switches parsed by `OptionParser` may take zero or one arguments.
-
-  The following switches types take no arguments:
-
-    * `:boolean` - sets the value to `true` when given (see also the
-      "Negation switches" section below)
-    * `:count` - counts the number of times the switch is given
-
-  The following switches take one argument:
-
-    * `:integer` - parses the value as an integer
-    * `:float` - parses the value as a float
-    * `:string` - parses the value as a string
-
-  If a switch can't be parsed according to the given type, it is
-  returned in the invalid options list.
-
-  ### Modifiers
-
-  Switches can be specified with modifiers, which change how
-  they behave. The following modifiers are supported:
-
-    * `:keep` - keeps duplicated items instead of overriding them;
-      works with all types except `:count`. Specifying `switch_name: :keep`
-      assumes the type of `:switch_name` will be `:string`.
-
-  To use `:keep` with a type other than `:string`, use a list as the type
-  for the switch. For example: `[foo: [:integer, :keep]]`.
-
-  ### Negation switches
-
-  In case a switch `SWITCH` is specified to have type `:boolean`, it may be
-  passed as `--no-SWITCH` as well which will set the option to `false`:
-
-      iex> OptionParser.parse(["--no-op", "path/to/file"], switches: [op: :boolean])
-      {[op: false], ["path/to/file"], []}
-
-  ### Parsing unknown switches
-
-  When the `:switches` option is given, `OptionParser` will attempt to parse
-  unknown switches:
-
-      iex> OptionParser.parse(["--debug"], switches: [key: :string])
-      {[debug: true], [], []}
-
-  Even though we haven't specified `--debug` in the list of switches, it is part
-  of the returned options. This would also work:
-
-      iex> OptionParser.parse(["--debug", "value"], switches: [key: :string])
-      {[debug: "value"], [], []}
-
-  Switches followed by a value will be assigned the value, as a string. Switches
-  without an argument will be set automatically to `true`. Since we cannot assert
-  the type of the switch value, it is preferred to use the `:strict` option that
-  accepts only known switches and always verify their types.
-
-  If you do want to parse unknown switches, remember that Elixir converts switches
-  to atoms. Since atoms are not garbage-collected, OptionParser will only parse
-  switches that translate to atoms used by the runtime to avoid leaking atoms.
-  For instance, the code below will discard the `--option-parser-example` switch
-  because the `:option_parser_example` atom is never used anywhere:
-
-      OptionParser.parse(["--option-parser-example"], switches: [debug: :boolean])
-      # The :option_parser_example atom is not used anywhere below
-
-  However, the code below would work as long as `:option_parser_example` atom is
-  used at some point later (or earlier) **in the same module**:
-
-      {opts, _, _} = OptionParser.parse(["--option-parser-example"], switches: [debug: :boolean])
-      opts[:option_parser_example]
-
-  In other words, Elixir will do the correct thing and only parse options that are
-  used by the runtime, ignoring all others. If you would like to parse all switches,
-  regardless if they exist or not, you can force creation of atoms by passing
-  `allow_nonexistent_atoms: true` as option. Use this option with care. It is only
-  useful when you are building command-line applications that receive
-  dynamically-named arguments and must be avoided in long-running systems.
-
-  ## Aliases
-
-  A set of aliases can be specified in the `:aliases` option:
-
-      iex> OptionParser.parse(["-d"], aliases: [d: :debug], strict: [debug: :boolean])
-      {[debug: true], [], []}
+     1. parsed switches,
+     2. remaining arguments,
+     3. invalid options.

  ## Examples

-  Here are some examples of working with different types and modifiers:
+      iex> OptionParser.parse(["--debug"])
+      {[debug: true], [], []}
+
+      iex> OptionParser.parse(["--source", "lib"])
+      {[source: "lib"], [], []}
+
+      iex> OptionParser.parse(["--source-path", "lib", "test/enum_test.exs", "--verbose"])
+      {[source_path: "lib", verbose: true], ["test/enum_test.exs"], []}
+
+  By default, Elixir will try to automatically parse all switches.
+  Switches followed by a value will be assigned the value, as a string.
+  Switches without an argument, like `--debug` will automatically
+  be set to `true`.
+
+  Note: Elixir also converts the switches to underscore atoms, so
+  `--source-path` becomes `:source_path`, to better suit Elixir
+  conventions. This means that option names on the command line cannot contain
+  underscores; such options will be put in the invalid options list.
+
+  ## Switch Definitions
+
+  Often it is better to explicitly list the known
+  switches and their formats. The switches can be specified via two
+  alternative options:
+
+    * `:switches` - defines some switches. An attempt is still made to parse
+      switches that do not appear in the list.
+
+    * `:strict` - the switches are strict. Any switch that is not specified
+      in the list is returned in the invalid options list.
+
+  Note that you should only supply the `:switches` or `:strict` option. If you
+  supply both, an error will be raised.
+
+  For each switch, the following types are supported:
+
+    * `:boolean` - marks the given switch as a boolean. Boolean switches
+      never consume the following value unless it is `true` or
+      `false`.
+    * `:integer` - parses the switch as an integer.
+    * `:float`   - parses the switch as a float.
+    * `:string`  - returns the switch as a string.
+
+  If a switch can't be parsed, it is returned in the invalid options list.
+
+  The following extra "types" are supported:
+
+    * `:keep` - keeps duplicated items in the list instead of overriding them.
+
+  Note: if you want to use `:keep` with a non-string type, use a list, e.g.
+  `[foo: [:integer, :keep]]`.
+
+  Examples:

      iex> OptionParser.parse(["--unlock", "path/to/file"], strict: [unlock: :boolean])
      {[unlock: true], ["path/to/file"], []}
@@ -175,12 +86,6 @@ defmodule OptionParser do
      iex> OptionParser.parse(["--limit", "xyz"], strict: [limit: :integer])
      {[], [], [{"--limit", "xyz"}]}

-      iex> OptionParser.parse(["--verbose"], switches: [verbose: :count])
-      {[verbose: 1], [], []}
-
-      iex> OptionParser.parse(["-v", "-v"], aliases: [v: :verbose], strict: [verbose: :count])
-      {[verbose: 2], [], []}
-
      iex> OptionParser.parse(["--unknown", "xyz"], strict: [])
      {[], ["xyz"], [{"--unknown", nil}]}

@@ -191,47 +96,25 @@ defmodule OptionParser do
      iex> OptionParser.parse(["--unlock", "path/to/file", "--unlock", "path/to/another/file"], strict: [unlock: :keep])
      {[unlock: "path/to/file", unlock: "path/to/another/file"], [], []}

+  ## Negation switches
+
+  In case a switch is declared as boolean, it may be passed as `--no-SWITCH`
+  which will set the option to `false`:
+
+      iex> OptionParser.parse(["--no-op", "path/to/file"], switches: [op: :boolean])
+      {[op: false], ["path/to/file"], []}
+
+  ## Aliases
+
+  A set of aliases can be given as options too:
+
+      iex> OptionParser.parse(["-d"], aliases: [d: :debug])
+      {[debug: true], [], []}
+
  """
  @spec parse(argv, options) :: {parsed, argv, errors}
  def parse(argv, opts \\ []) when is_list(argv) and is_list(opts) do
-    do_parse(argv, build_config(opts), [], [], [], true)
-  end
-
-  @doc """
-  The same as `parse/2` but raises an `OptionParser.ParseError`
-  exception if any invalid options are given.
-
-  If there are no errors, returns a `{parsed, rest}` tuple where:
-
-    * `parsed` is the list of parsed switches (same as in `parse/2`)
-    * `rest` is the list of arguments (same as in `parse/2`)
-
-  ## Examples
-
-      iex> OptionParser.parse!(["--debug", "path/to/file"], strict: [debug: :boolean])
-      {[debug: true], ["path/to/file"]}
-
-      iex> OptionParser.parse!(["--limit", "xyz"], strict: [limit: :integer])
-      ** (OptionParser.ParseError) 1 error found!
-      --limit : Expected type integer, got "xyz"
-
-      iex> OptionParser.parse!(["--unknown", "xyz"], strict: [])
-      ** (OptionParser.ParseError) 1 error found!
-      --unknown : Unknown option
-
-      iex> OptionParser.parse!(["-l", "xyz", "-f", "bar"],
-      ...>                     switches: [limit: :integer, foo: :integer], aliases: [l: :limit, f: :foo])
-      ** (OptionParser.ParseError) 2 errors found!
-      -l : Expected type integer, got "xyz"
-      -f : Expected type integer, got "bar"
-
-  """
-  @spec parse!(argv, options) :: {parsed, argv} | no_return
-  def parse!(argv, opts \\ []) when is_list(argv) and is_list(opts) do
-    case parse(argv, opts) do
-      {parsed, args, []} -> {parsed, args}
-      {_, _, errors} -> raise ParseError, format_errors(errors, opts)
-    end
+    do_parse(argv, compile_config(opts), [], [], [], true)
  end

  @doc """
@@ -242,82 +125,45 @@ defmodule OptionParser do

  ## Example

-      iex> OptionParser.parse_head(["--source", "lib", "test/enum_test.exs", "--verbose"],
-      ...>                         switches: [source: :string, verbose: :boolean])
+      iex> OptionParser.parse_head(["--source", "lib", "test/enum_test.exs", "--verbose"])
      {[source: "lib"], ["test/enum_test.exs", "--verbose"], []}

-      iex> OptionParser.parse_head(["--verbose", "--source", "lib", "test/enum_test.exs", "--unlock"],
-      ...>                         switches: [source: :string, verbose: :boolean, unlock: :boolean])
+      iex> OptionParser.parse_head(["--verbose", "--source", "lib", "test/enum_test.exs", "--unlock"])
      {[verbose: true, source: "lib"], ["test/enum_test.exs", "--unlock"], []}

  """
  @spec parse_head(argv, options) :: {parsed, argv, errors}
  def parse_head(argv, opts \\ []) when is_list(argv) and is_list(opts) do
-    do_parse(argv, build_config(opts), [], [], [], false)
-  end
-
-  @doc """
-  The same as `parse_head/2` but raises an `OptionParser.ParseError`
-  exception if any invalid options are given.
-
-  If there are no errors, returns a `{parsed, rest}` tuple where:
-
-    * `parsed` is the list of parsed switches (same as in `parse_head/2`)
-    * `rest` is the list of arguments (same as in `parse_head/2`)
-
-  ## Examples
-
-      iex> OptionParser.parse_head!(["--source", "lib", "path/to/file", "--verbose"],
-      ...>                         switches: [source: :string, verbose: :boolean])
-      {[source: "lib"], ["path/to/file", "--verbose"]}
-
-      iex> OptionParser.parse_head!(["--number", "lib", "test/enum_test.exs", "--verbose"],
-      ...>                          strict: [number: :integer])
-      ** (OptionParser.ParseError) 1 error found!
-      --number : Expected type integer, got "lib"
-
-      iex> OptionParser.parse_head!(["--verbose", "--source", "lib", "test/enum_test.exs", "--unlock"],
-      ...>                          strict: [verbose: :integer, source: :integer])
-      ** (OptionParser.ParseError) 2 errors found!
-      --verbose : Missing argument of type integer
-      --source : Expected type integer, got "lib"
-
-  """
-  @spec parse_head!(argv, options) :: {parsed, argv} | no_return
-  def parse_head!(argv, opts \\ []) when is_list(argv) and is_list(opts) do
-    case parse_head(argv, opts) do
-      {parsed, args, []} -> {parsed, args}
-      {_, _, errors} -> raise ParseError, format_errors(errors, opts)
-    end
+    do_parse(argv, compile_config(opts), [], [], [], false)
  end

  defp do_parse([], _config, opts, args, invalid, _all?) do
    {Enum.reverse(opts), Enum.reverse(args), Enum.reverse(invalid)}
  end

-  defp do_parse(argv, %{switches: switches} = config, opts, args, invalid, all?) do
-    case next_with_config(argv, config) do
+  defp do_parse(argv, {aliases, switches, strict}=config, opts, args, invalid, all?) do
+    case next(argv, aliases, switches, strict) do
      {:ok, option, value, rest} ->
-        # the option exists and it was successfully parsed
-        kinds = List.wrap(Keyword.get(switches, option))
-        new_opts = store_option(opts, option, value, kinds)
+        # the option exist and it was successfully parsed
+        kinds = List.wrap Keyword.get(switches, option)
+        new_opts = do_store_option(opts, option, value, kinds)
        do_parse(rest, config, new_opts, args, invalid, all?)

      {:invalid, option, value, rest} ->
        # the option exist but it has wrong value
-        do_parse(rest, config, opts, args, [{option, value} | invalid], all?)
+        do_parse(rest, config, opts, args, [{option, value}|invalid], all?)

      {:undefined, option, _value, rest} ->
-        invalid = if config.strict?, do: [{option, nil} | invalid], else: invalid
-        do_parse(rest, config, opts, args, invalid, all?)
+        # the option does not exist (for strict cases)
+        do_parse(rest, config, opts, args, [{option, nil}|invalid], all?)

-      {:error, ["--" | rest]} ->
+      {:error, ["--"|rest]} ->
        {Enum.reverse(opts), Enum.reverse(args, rest), Enum.reverse(invalid)}

-      {:error, [arg | rest] = remaining_args} ->
+      {:error, [arg|rest]=remaining_args} ->
        # there is no option
        if all? do
-          do_parse(rest, config, opts, [arg | args], invalid, all?)
+          do_parse(rest, config, opts, [arg|args], invalid, all?)
        else
          {Enum.reverse(opts), Enum.reverse(args, remaining_args), Enum.reverse(invalid)}
        end
@@ -328,172 +174,102 @@ defmodule OptionParser do
  Low-level function that parses one option.

  It accepts the same options as `parse/2` and `parse_head/2`
-  as both functions are built on top of this function. This function
+  as both functions are built on top of next. This function
  may return:

    * `{:ok, key, value, rest}` - the option `key` with `value` was
      successfully parsed

    * `{:invalid, key, value, rest}` - the option `key` is invalid with `value`
-      (returned when the value cannot be parsed according to the switch type)
+      (returned when the switch type does not match the one given via the
+      command line)

    * `{:undefined, key, value, rest}` - the option `key` is undefined
-      (returned in strict mode when the switch is unknown or on nonexistent atoms)
-
-    * `{:error, rest}` - there are no switches at the head of the given `argv`
+      (returned in strict mode when the switch is unknown)

+    * `{:error, rest}` - there are no switches at the top of the given argv
  """
+
  @spec next(argv, options) ::
-          {:ok, key :: atom, value :: term, argv}
-          | {:invalid, String.t(), String.t() | nil, argv}
-          | {:undefined, String.t(), String.t() | nil, argv}
-          | {:error, argv}
+        {:ok, key :: atom, value :: term, argv} |
+        {:invalid, String.t, String.t | nil, argv} |
+        {:undefined, String.t, String.t | nil, argv} |
+        {:error, argv}

  def next(argv, opts \\ []) when is_list(argv) and is_list(opts) do
-    next_with_config(argv, build_config(opts))
+    {aliases, switches, strict} = compile_config(opts)
+    next(argv, aliases, switches, strict)
  end

-  defp next_with_config([], _config) do
+  defp next([], _aliases, _switches, _strict) do
    {:error, []}
  end

-  defp next_with_config(["--" | _] = argv, _config) do
+  defp next(["--"|_]=argv, _aliases, _switches, _strict) do
    {:error, argv}
  end

-  defp next_with_config(["-" | _] = argv, _config) do
+  defp next(["-"|_]=argv, _aliases, _switches, _strict) do
    {:error, argv}
  end

-  defp next_with_config(["- " <> _ | _] = argv, _config) do
+  defp next(["- " <> _|_]=argv, _aliases, _switches, _strict) do
    {:error, argv}
  end

-  # Handles --foo or --foo=bar
-  defp next_with_config(["--" <> option | rest], config) do
+  defp next(["-" <> option|rest], aliases, switches, strict) do
    {option, value} = split_option(option)
+    opt_name_bin = "-" <> option
+    tagged = tag_option(option, switches, aliases)

-    if String.contains?(option, ["_"]) do
-      {:undefined, "--" <> option, value, rest}
+    if strict and not option_defined?(tagged, switches) do
+      {:undefined, opt_name_bin, value, rest}
    else
-      tagged = tag_option(option, config)
-      next_tagged(tagged, value, "--" <> option, rest, config)
-    end
-  end
-
-  # Handles -a, -abc, -abc=something
-  defp next_with_config(["-" <> option | rest] = argv, config) do
-    %{allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-    {option, value} = split_option(option)
-    original = "-" <> option
-    letters = String.graphemes(option)
-
-    cond do
-      is_nil(value) and negative_number?(original) ->
-        {:error, argv}
-
-      String.contains?(option, ["-", "_"]) ->
-        {:undefined, original, value, rest}
-
-      tl(letters) == [] ->
-        # We have a regular one-letter alias here
-        tagged = tag_oneletter_alias(option, config)
-        next_tagged(tagged, value, original, rest, config)
-
-      true ->
-        key = get_option_key(option, allow_nonexistent_atoms?)
-        option_key = config.aliases[key]
-
-        if key && option_key do
-          # TODO: Remove this in Elixir v2.0
-          IO.warn("multi-letter aliases are deprecated, got: #{inspect(key)}")
-          next_tagged({:default, option_key}, value, original, rest, config)
-        else
-          next_with_config(expand_multiletter_alias(letters, value) ++ rest, config)
-        end
-    end
-  end
-
-  defp next_with_config(argv, _config) do
-    {:error, argv}
-  end
-
-  defp next_tagged(:unknown, value, original, rest, _) do
-    {value, _kinds, rest} = normalize_value(value, [], rest)
-    {:undefined, original, value, rest}
-  end
-
-  defp next_tagged({tag, option}, value, original, rest, %{switches: switches, strict?: strict?}) do
-    if strict? and not Keyword.has_key?(switches, option) do
-      {:undefined, original, value, rest}
-    else
-      {kinds, value} = normalize_tag(tag, option, value, switches)
-      {value, kinds, rest} = normalize_value(value, kinds, rest)
-
+      {opt_name, kinds, value} = normalize_option(tagged, value, switches)
+      {value, kinds, rest} = normalize_value(value, kinds, rest, strict)
      case validate_option(value, kinds) do
-        {:ok, new_value} -> {:ok, option, new_value, rest}
-        :invalid -> {:invalid, original, value, rest}
+        {:ok, new_value} -> {:ok, opt_name, new_value, rest}
+        :invalid         -> {:invalid, opt_name_bin, value, rest}
      end
    end
  end

+  defp next(argv, _aliases, _switches, _strict) do
+    {:error, argv}
+  end
+
  @doc """
-  Receives a key-value enumerable and converts it to `t:argv/0`.
+  Receives a key-value enumerable and converts it to argv.

-  Keys must be atoms. Keys with `nil` value are discarded,
+  Keys must be atoms. Keys with nil value are discarded,
  boolean values are converted to `--key` or `--no-key`
-  (if the value is `true` or `false`, respectively),
-  and all other values are converted using `Kernel.to_string/1`.
-
-  It is advised to pass to `to_argv/2` the same set of `options`
-  given to `parse/2`. Some switches can only be reconstructed
-  correctly with the `switches` information in hand.
+  and all other values are converted using `to_string/1`.

  ## Examples

-      iex> OptionParser.to_argv(foo_bar: "baz")
+      iex>  OptionParser.to_argv([foo_bar: "baz"])
      ["--foo-bar", "baz"]
-      iex> OptionParser.to_argv(bool: true, bool: false, discarded: nil)
+
+      iex>  OptionParser.to_argv([bool: true, bool: false, discarded: nil])
      ["--bool", "--no-bool"]

-  Some switches will output different values based on the switches
-  flag:
-
-      iex> OptionParser.to_argv([number: 2], switches: [])
-      ["--number", "2"]
-      iex> OptionParser.to_argv([number: 2], switches: [number: :count])
-      ["--number", "--number"]
-
  """
-  @spec to_argv(Enumerable.t(), options) :: argv
-  def to_argv(enum, opts \\ []) do
-    switches = Keyword.get(opts, :switches, [])
-
+  @spec to_argv(Enumerable.t) :: argv
+  def to_argv(enum) do
    Enum.flat_map(enum, fn
-      {_key, nil} -> []
-      {key, true} -> [to_switch(key)]
+      {_key, nil}  -> []
+      {key, true}  -> [to_switch(key)]
      {key, false} -> [to_switch(key, "--no-")]
-      {key, value} -> to_argv(key, value, switches)
+      {key, value} -> [to_switch(key), to_string(value)]
    end)
  end

-  defp to_argv(key, value, switches) do
-    if switches[key] == :count do
-      List.duplicate(to_switch(key), value)
-    else
-      [to_switch(key), to_string(value)]
-    end
-  end
-
  defp to_switch(key, prefix \\ "--") when is_atom(key) do
    prefix <> String.replace(Atom.to_string(key), "_", "-")
  end

  @doc ~S"""
-  Splits a string into `t:argv/0` chunks.
-
-  This function splits the given `string` into a list of strings in a similar
-  way to many shells.
+  Splits a string into argv chunks.

  ## Examples

@@ -502,11 +278,10 @@ defmodule OptionParser do

      iex> OptionParser.split("foo \"bar baz\"")
      ["foo", "bar baz"]
-
  """
-  @spec split(String.t()) :: argv
-  def split(string) when is_binary(string) do
-    do_split(String.trim_leading(string, " "), "", [], nil)
+  @spec split(String.t) :: argv
+  def split(string) do
+    do_split(strip_leading_spaces(string), "", [], nil)
  end

  # If we have an escaped quote, simply remove the escape
@@ -518,7 +293,8 @@ defmodule OptionParser do
    do: do_split(t, buffer, acc, quote)

  # If we have a quote and we were inside it, close it
-  defp do_split(<<quote, t::binary>>, buffer, acc, quote), do: do_split(t, buffer, acc, nil)
+  defp do_split(<<quote, t::binary>>, buffer, acc, quote),
+    do: do_split(t, buffer, acc, nil)

  # If we have an escaped quote/space, simply remove the escape as long as we are not inside a quote
  defp do_split(<<?\\, h, t::binary>>, buffer, acc, nil) when h in [?\s, ?', ?"],
@@ -526,7 +302,7 @@ defmodule OptionParser do

  # If we have space and we are outside of a quote, start new segment
  defp do_split(<<?\s, t::binary>>, buffer, acc, nil),
-    do: do_split(String.trim_leading(t, " "), "", [buffer | acc], nil)
+    do: do_split(strip_leading_spaces(t), "", [buffer|acc], nil)

  # All other characters are moved to buffer
  defp do_split(<<h, t::binary>>, buffer, acc, quote) do
@@ -534,247 +310,186 @@ defmodule OptionParser do
  end

  # Finish the string expecting a nil marker
-  defp do_split(<<>>, "", acc, nil), do: Enum.reverse(acc)
+  defp do_split(<<>>, "", acc, nil),
+    do: Enum.reverse(acc)

-  defp do_split(<<>>, buffer, acc, nil), do: Enum.reverse([buffer | acc])
+  defp do_split(<<>>, buffer, acc, nil),
+    do: Enum.reverse([buffer|acc])

  # Otherwise raise
  defp do_split(<<>>, _, _acc, marker) do
    raise "argv string did not terminate properly, a #{<<marker>>} was opened but never closed"
  end

+  defp strip_leading_spaces(" " <> t), do: strip_leading_spaces(t)
+  defp strip_leading_spaces(t), do: t
+
  ## Helpers

-  defp build_config(opts) do
-    {switches, strict?} =
-      cond do
-        opts[:switches] && opts[:strict] ->
-          raise ArgumentError, ":switches and :strict cannot be given together"
+  defp compile_config(opts) do
+    aliases = opts[:aliases] || []

-        switches = opts[:switches] ->
-          {switches, false}
+    {switches, strict} = cond do
+      opts[:switches] && opts[:strict] ->
+        raise ArgumentError, ":switches and :strict cannot be given together"
+      s = opts[:switches] ->
+        {s, false}
+      s = opts[:strict] ->
+        {s, true}
+      true ->
+        {[], false}
+    end

-        strict = opts[:strict] ->
-          {strict, true}
-
-        true ->
-          # TODO: Remove this in Elixir v2.0
-          IO.warn("not passing the :switches or :strict option to OptionParser is deprecated")
-          {[], false}
-      end
-
-    %{
-      aliases: opts[:aliases] || [],
-      allow_nonexistent_atoms?: opts[:allow_nonexistent_atoms] || false,
-      strict?: strict?,
-      switches: switches
-    }
+    {aliases, switches, strict}
  end

  defp validate_option(value, kinds) do
-    {invalid?, value} =
-      cond do
-        :invalid in kinds ->
-          {true, value}
+    {is_invalid, value} = cond do
+      :invalid in kinds ->
+        {true, value}
+      :boolean in kinds ->
+        case value do
+          t when t in [true, "true"] -> {nil, true}
+          f when f in [false, "false"] -> {nil, false}
+          _ -> {true, value}
+        end
+      :integer in kinds ->
+        case Integer.parse(value) do
+          {value, ""} -> {nil, value}
+          _ -> {true, value}
+        end
+      :float in kinds ->
+        case Float.parse(value) do
+          {value, ""} -> {nil, value}
+          _ -> {true, value}
+        end
+      true ->
+        {nil, value}
+    end

-        :boolean in kinds ->
-          case value do
-            t when t in [true, "true"] -> {false, true}
-            f when f in [false, "false"] -> {false, false}
-            _ -> {true, value}
-          end
-
-        :count in kinds ->
-          case value do
-            nil -> {false, 1}
-            _ -> {true, value}
-          end
-
-        :integer in kinds ->
-          case Integer.parse(value) do
-            {value, ""} -> {false, value}
-            _ -> {true, value}
-          end
-
-        :float in kinds ->
-          case Float.parse(value) do
-            {value, ""} -> {false, value}
-            _ -> {true, value}
-          end
-
-        true ->
-          {false, value}
-      end
-
-    if invalid? do
+    if is_invalid do
      :invalid
    else
      {:ok, value}
    end
  end

-  defp store_option(dict, option, value, kinds) do
+  defp do_store_option(dict, option, value, kinds) do
    cond do
-      :count in kinds ->
-        Keyword.update(dict, option, value, &(&1 + 1))
-
      :keep in kinds ->
-        [{option, value} | dict]
-
+        [{option, value}|dict]
      true ->
-        [{option, value} | Keyword.delete(dict, option)]
+        [{option, value}|Keyword.delete(dict, option)]
    end
  end

-  defp tag_option("no-" <> option = original, config) do
-    %{switches: switches, allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-
-    cond do
-      (negated = get_option_key(option, allow_nonexistent_atoms?)) &&
-          :boolean in List.wrap(switches[negated]) ->
-        {:negated, negated}
-
-      option_key = get_option_key(original, allow_nonexistent_atoms?) ->
-        {:default, option_key}
-
-      true ->
-        :unknown
-    end
+  defp tag_option(<<?-, option::binary>>, switches, _aliases) do
+    get_negated(option, switches)
  end

-  defp tag_option(option, config) do
-    %{allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-
-    if option_key = get_option_key(option, allow_nonexistent_atoms?) do
-      {:default, option_key}
+  defp tag_option(option, _switches, aliases) when is_binary(option) do
+    opt = get_option(option)
+    if alias = aliases[opt] do
+      {:default, alias}
    else
      :unknown
    end
  end

-  defp tag_oneletter_alias(alias, config) when is_binary(alias) do
-    %{aliases: aliases, allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-
-    if option_key = aliases[to_existing_key(alias, allow_nonexistent_atoms?)] do
-      {:default, option_key}
-    else
-      :unknown
-    end
+  defp option_defined?(:unknown, _switches) do
+    false
  end

-  defp expand_multiletter_alias(letters, value) do
-    {last, expanded} =
-      letters
-      |> Enum.map(&("-" <> &1))
-      |> List.pop_at(-1)
-
-    expanded ++ [last <> if(value, do: "=" <> value, else: "")]
+  defp option_defined?({:negated, option}, switches) do
+    Keyword.has_key?(switches, option)
  end

-  defp normalize_tag(:negated, option, value, switches) do
+  defp option_defined?({:default, option}, switches) do
+    Keyword.has_key?(switches, option)
+  end
+
+  defp normalize_option(:unknown, value, _switches) do
+    {nil, [:invalid], value}
+  end
+
+  defp normalize_option({:negated, option}, value, switches) do
    if value do
-      {[:invalid], value}
+      {option, [:invalid], value}
    else
-      {List.wrap(switches[option]), false}
+      {option, List.wrap(switches[option]), false}
    end
  end

-  defp normalize_tag(:default, option, value, switches) do
-    {List.wrap(switches[option]), value}
+  defp normalize_option({:default, option}, value, switches) do
+    {option, List.wrap(switches[option]), value}
  end

-  defp normalize_value(nil, kinds, t) do
+  defp normalize_value(nil, kinds, t, strict) do
+    nil_or_true = if strict, do: nil, else: true
    cond do
      :boolean in kinds ->
        {true, kinds, t}
-
-      :count in kinds ->
-        {nil, kinds, t}
-
      value_in_tail?(t) ->
-        [h | t] = t
+        [h|t] = t
        {h, kinds, t}
-
      kinds == [] ->
-        {true, kinds, t}
-
+        {nil_or_true, kinds, t}
      true ->
        {nil, [:invalid], t}
    end
  end

-  defp normalize_value(value, kinds, t) do
+  defp normalize_value(value, kinds, t, _) do
    {value, kinds, t}
  end

-  defp value_in_tail?(["-" | _]), do: true
-  defp value_in_tail?(["- " <> _ | _]), do: true
-  defp value_in_tail?(["-" <> arg | _]), do: negative_number?("-" <> arg)
-  defp value_in_tail?([]), do: false
-  defp value_in_tail?(_), do: true
+  defp value_in_tail?(["-"|_]),       do: true
+  defp value_in_tail?(["- " <> _|_]), do: true
+  defp value_in_tail?(["-" <> _|_]),  do: false
+  defp value_in_tail?([]),            do: false
+  defp value_in_tail?(_),             do: true

  defp split_option(option) do
    case :binary.split(option, "=") do
-      [h] -> {h, nil}
+      [h]    -> {h, nil}
      [h, t] -> {h, t}
    end
  end

  defp to_underscore(option), do: to_underscore(option, <<>>)
-  defp to_underscore("-" <> rest, acc), do: to_underscore(rest, acc <> "_")
-  defp to_underscore(<<c>> <> rest, acc), do: to_underscore(rest, <<acc::binary, c>>)
+
+  defp to_underscore("_" <> _rest, _acc), do: nil
+
+  defp to_underscore("-" <> rest, acc),
+    do: to_underscore(rest, acc <> "_")
+
+  defp to_underscore(<<c>> <> rest, acc),
+    do: to_underscore(rest, <<acc::binary, c>>)
+
  defp to_underscore(<<>>, acc), do: acc

-  defp get_option_key(option, allow_nonexistent_atoms?) do
-    option
-    |> to_underscore()
-    |> to_existing_key(allow_nonexistent_atoms?)
-  end
-
-  defp to_existing_key(option, true), do: String.to_atom(option)
-
-  defp to_existing_key(option, false) do
-    try do
-      String.to_existing_atom(option)
-    rescue
-      ArgumentError -> nil
+  defp get_option(option) do
+    if str = to_underscore(option) do
+      String.to_atom(str)
    end
  end

-  defp negative_number?(arg) do
-    match?({_, ""}, Float.parse(arg))
-  end
-
-  defp format_errors([_ | _] = errors, opts) do
-    types = opts[:switches] || opts[:strict]
-    error_count = length(errors)
-    error = if error_count == 1, do: "error", else: "errors"
-
-    "#{error_count} #{error} found!\n" <>
-      Enum.map_join(errors, "\n", &format_error(&1, opts, types))
-  end
-
-  defp format_error({option, nil}, opts, types) do
-    if type = get_type(option, opts, types) do
-      "#{option} : Missing argument of type #{type}"
-    else
-      "#{option} : Unknown option"
+  defp get_negated("no-" <> rest = original, switches) do
+    cond do
+      (negated = get_option(rest)) && :boolean in List.wrap(switches[negated]) ->
+        {:negated, negated}
+      option = get_option(original) ->
+        {:default, option}
+      true ->
+        :unknown
    end
  end

-  defp format_error({option, value}, opts, types) do
-    type = get_type(option, opts, types)
-    "#{option} : Expected type #{type}, got #{inspect(value)}"
-  end
-
-  defp get_type(option, opts, types) do
-    allow_nonexistent_atoms? = opts[:allow_nonexistent_atoms] || false
-    key = option |> String.trim_leading("-") |> get_option_key(allow_nonexistent_atoms?)
-
-    if option_key = opts[:aliases][key] do
-      types[option_key]
+  defp get_negated(rest, _switches) do
+    if option = get_option(rest) do
+      {:default, option}
    else
-      types[key]
+      :unknown
    end
  end
 end
@@ -3,24 +3,23 @@ defmodule Path do
  This module provides conveniences for manipulating or
  retrieving file system paths.

-  The functions in this module may receive a chardata as
+  The functions in this module may receive a char data as
  argument (i.e. a string or a list of characters / string)
  and will always return a string (encoded in UTF-8).

  The majority of the functions in this module do not
  interact with the file system, except for a few functions
-  that require it (like `wildcard/2` and `expand/1`).
+  that require it (like `wildcard/1` and `expand/1`).
  """

+  alias :filename, as: FN
  @type t :: :unicode.chardata()

  @doc """
  Converts the given path to an absolute one. Unlike
  `expand/1`, no attempt is made to resolve `..`, `.` or `~`.

-  ## Examples
-
-  ### Unix
+  ## Unix examples

      Path.absname("foo")
      #=> "/usr/local/foo"
@@ -28,24 +27,22 @@ defmodule Path do
      Path.absname("../x")
      #=> "/usr/local/../x"

-  ### Windows
+  ## Windows

      Path.absname("foo").
-      #=> "D:/usr/local/foo"
+      "D:/usr/local/foo"
      Path.absname("../x").
-      #=> "D:/usr/local/../x"
+      "D:/usr/local/../x"

  """
  @spec absname(t) :: binary
  def absname(path) do
-    absname(path, System.cwd!())
+    absname(path, System.cwd!)
  end

  @doc """
-  Builds a path from `relative_to` to `path`.
-
-  If `path` is already an absolute path, `relative_to` is ignored. See also
-  `relative_to/2`.
+  Builds a path from `relative_to` to `path`. If `path` is already
+  an absolute path, `relative_to` is ignored. See also `relative_to/2`.

  Unlike `expand/2`, no attempt is made to
  resolve `..`, `.` or `~`.
@@ -62,14 +59,9 @@ defmodule Path do
  @spec absname(t, t) :: binary
  def absname(path, relative_to) do
    path = IO.chardata_to_string(path)
-
    case type(path) do
-      :relative ->
-        absname_join(relative_to, path)
-
-      :absolute ->
-        absname_join([path])
-
+      :relative -> absname_join(relative_to, path)
+      :absolute -> absname_join([path])
      :volumerelative ->
        relative_to = IO.chardata_to_string(relative_to)
        absname_vr(split(path), split(relative_to), relative_to)
@@ -77,66 +69,60 @@ defmodule Path do
  end

  # Absolute path on current drive
-  defp absname_vr(["/" | rest], [volume | _], _relative), do: absname_join([volume | rest])
+  defp absname_vr(["/"|rest], [volume|_], _relative),
+    do: absname_join([volume|rest])

  # Relative to current directory on current drive.
-  defp absname_vr([<<x, ?:>> | rest], [<<x, _::binary>> | _], relative),
+  defp absname_vr([<<x, ?:>>|rest], [<<x, _::binary>>|_], relative),
    do: absname(absname_join(rest), relative)

  # Relative to current directory on another drive.
-  defp absname_vr([<<x, ?:>> | name], _, _relative) do
+  defp absname_vr([<<x, ?:>>|name], _, _relative) do
    cwd =
      case :file.get_cwd([x, ?:]) do
-        {:ok, dir} -> IO.chardata_to_string(dir)
+        {:ok, dir}  -> IO.chardata_to_string(dir)
        {:error, _} -> <<x, ?:, ?/>>
      end
-
    absname(absname_join(name), cwd)
  end

  # Joins a list
-  defp absname_join([name1, name2 | rest]), do: absname_join([absname_join(name1, name2) | rest])
-
-  defp absname_join([name]),
-    do: do_absname_join(IO.chardata_to_string(name), <<>>, [], major_os_type())
+  defp absname_join([name1, name2|rest]), do:
+    absname_join([absname_join(name1, name2)|rest])
+  defp absname_join([name]), do:
+    do_absname_join(IO.chardata_to_string(name), <<>>, [], major_os_type())

  # Joins two paths
  defp absname_join(left, right),
    do: do_absname_join(IO.chardata_to_string(left), relative(right), [], major_os_type())

-  defp do_absname_join(<<uc_letter, ?:, rest::binary>>, relativename, [], :win32)
-       when uc_letter in ?A..?Z do
-    do_absname_join(rest, relativename, [?:, uc_letter + ?a - ?A], :win32)
-  end
+  defp do_absname_join(<<uc_letter, ?:, rest::binary>>, relativename, [], :win32) when uc_letter in ?A..?Z, do:
+    do_absname_join(rest, relativename, [?:, uc_letter+?a-?A], :win32)
+  defp do_absname_join(<<?\\, rest::binary>>, relativename, result, :win32), do:
+    do_absname_join(<<?/, rest::binary>>, relativename, result, :win32)
+  defp do_absname_join(<<?/, rest::binary>>, relativename, [?., ?/|result], os_type), do:
+    do_absname_join(rest, relativename, [?/|result], os_type)
+  defp do_absname_join(<<?/, rest::binary>>, relativename, [?/|result], os_type), do:
+    do_absname_join(rest, relativename, [?/|result], os_type)
+  defp do_absname_join(<<>>, <<>>, result, os_type), do:
+    IO.iodata_to_binary(reverse_maybe_remove_dirsep(result, os_type))
+  defp do_absname_join(<<>>, relativename, [?:|rest], :win32), do:
+    do_absname_join(relativename, <<>>, [?:|rest], :win32)
+  defp do_absname_join(<<>>, relativename, [?/|result], os_type), do:
+    do_absname_join(relativename, <<>>, [?/|result], os_type)
+  defp do_absname_join(<<>>, relativename, result, os_type), do:
+    do_absname_join(relativename, <<>>, [?/|result], os_type)
+  defp do_absname_join(<<char, rest::binary>>, relativename, result, os_type), do:
+    do_absname_join(rest, relativename, [char|result], os_type)

-  defp do_absname_join(<<?\\, rest::binary>>, relativename, result, :win32),
-    do: do_absname_join(<<?/, rest::binary>>, relativename, result, :win32)
-
-  defp do_absname_join(<<?/, rest::binary>>, relativename, [?., ?/ | result], os_type),
-    do: do_absname_join(rest, relativename, [?/ | result], os_type)
-
-  defp do_absname_join(<<?/, rest::binary>>, relativename, [?/ | result], os_type),
-    do: do_absname_join(rest, relativename, [?/ | result], os_type)
-
-  defp do_absname_join(<<>>, <<>>, result, os_type),
-    do: IO.iodata_to_binary(reverse_maybe_remove_dir_sep(result, os_type))
-
-  defp do_absname_join(<<>>, relativename, [?: | rest], :win32),
-    do: do_absname_join(relativename, <<>>, [?: | rest], :win32)
-
-  defp do_absname_join(<<>>, relativename, [?/ | result], os_type),
-    do: do_absname_join(relativename, <<>>, [?/ | result], os_type)
-
-  defp do_absname_join(<<>>, relativename, result, os_type),
-    do: do_absname_join(relativename, <<>>, [?/ | result], os_type)
-
-  defp do_absname_join(<<char, rest::binary>>, relativename, result, os_type),
-    do: do_absname_join(rest, relativename, [char | result], os_type)
-
-  defp reverse_maybe_remove_dir_sep([?/, ?:, letter], :win32), do: [letter, ?:, ?/]
-  defp reverse_maybe_remove_dir_sep([?/], _), do: [?/]
-  defp reverse_maybe_remove_dir_sep([?/ | name], _), do: :lists.reverse(name)
-  defp reverse_maybe_remove_dir_sep(name, _), do: :lists.reverse(name)
+  defp reverse_maybe_remove_dirsep([?/, ?:, letter], :win32), do:
+    [letter, ?:, ?/]
+  defp reverse_maybe_remove_dirsep([?/], _), do:
+    [?/]
+  defp reverse_maybe_remove_dirsep([?/|name], _), do:
+    :lists.reverse(name)
+  defp reverse_maybe_remove_dirsep(name, _), do:
+    :lists.reverse(name)

  @doc """
  Converts the path to an absolute one and expands
@@ -145,21 +131,20 @@ defmodule Path do
  ## Examples

      Path.expand("/foo/bar/../bar")
-      #=> "/foo/bar"
+      "/foo/bar"

  """
  @spec expand(t) :: binary
  def expand(path) do
-    expand_dot(absname(expand_home(path), System.cwd!()))
+    expand_dot absname(expand_home(path), System.cwd!)
  end

  @doc """
  Expands the path relative to the path given as the second argument
-  expanding any `.` and `..` characters.
+  expanding any `.` and `..` characters. If the path is already an
+  absolute path, `relative_to` is ignored.

-  If the path is already an absolute path, `relative_to` is ignored.
-
-  Note that this function treats a `path` with a leading `~` as
+  Note, that this function treats `path` with a leading `~` as
  an absolute one.

  The second argument is first expanded to an absolute path.
@@ -178,15 +163,13 @@ defmodule Path do
  """
  @spec expand(t, t) :: binary
  def expand(path, relative_to) do
-    expand_dot(absname(absname(expand_home(path), expand_home(relative_to)), System.cwd!()))
+    expand_dot absname(absname(expand_home(path), expand_home(relative_to)), System.cwd!)
  end

  @doc """
  Returns the path type.

-  ## Examples
-
-  ### Unix
+  ## Unix examples

      Path.type("/")                #=> :absolute
      Path.type("/usr/local/bin")   #=> :absolute
@@ -194,7 +177,7 @@ defmodule Path do
      Path.type("../usr/local/bin") #=> :relative
      Path.type("~/file")           #=> :relative

-  ### Windows
+  ## Windows examples

      Path.type("D:/usr/local/bin") #=> :absolute
      Path.type("usr/local/bin")    #=> :relative
@@ -203,24 +186,20 @@ defmodule Path do

  """
  @spec type(t) :: :absolute | :relative | :volumerelative
-  def type(name)
-      when is_list(name)
-      when is_binary(name) do
-    pathtype(name, major_os_type()) |> elem(0)
+  def type(name) when is_list(name) or is_binary(name) do
+    pathtype(name, major_os_type) |> elem(0)
  end

  @doc """
  Forces the path to be a relative path.

-  ## Examples
-
-  ### Unix
+  ## Unix examples

      Path.relative("/usr/local/bin")   #=> "usr/local/bin"
      Path.relative("usr/local/bin")    #=> "usr/local/bin"
      Path.relative("../usr/local/bin") #=> "../usr/local/bin"

-  ### Windows
+  ## Windows examples

      Path.relative("D:/usr/local/bin") #=> "usr/local/bin"
      Path.relative("usr/local/bin")    #=> "usr/local/bin"
@@ -236,58 +215,56 @@ defmodule Path do
  defp relative(name, os_type) do
    pathtype(name, os_type)
    |> elem(1)
-    |> IO.chardata_to_string()
+    |> IO.chardata_to_string
  end

  defp pathtype(name, os_type) do
    case os_type do
      :win32 -> win32_pathtype(name)
-      _ -> unix_pathtype(name)
+      _      -> unix_pathtype(name)
    end
  end

-  defp unix_pathtype(path) when path in ["/", '/'], do: {:absolute, "."}
-  defp unix_pathtype(<<?/, relative::binary>>), do: {:absolute, relative}
-  defp unix_pathtype([?/ | relative]), do: {:absolute, relative}
-  defp unix_pathtype([list | rest]) when is_list(list), do: unix_pathtype(list ++ rest)
-  defp unix_pathtype(relative), do: {:relative, relative}
+  defp unix_pathtype(<<?/, relative::binary>>), do:
+    {:absolute, relative}
+  defp unix_pathtype([?/|relative]), do:
+    {:absolute, relative}
+  defp unix_pathtype([list|rest]) when is_list(list), do:
+    unix_pathtype(list ++ rest)
+  defp unix_pathtype(relative), do:
+    {:relative, relative}

  @slash [?/, ?\\]

-  defp win32_pathtype([list | rest]) when is_list(list), do: win32_pathtype(list ++ rest)
+  defp win32_pathtype([list|rest]) when is_list(list), do:
+    win32_pathtype(list++rest)
+  defp win32_pathtype([char, list|rest]) when is_list(list), do:
+    win32_pathtype([char|list++rest])
+  defp win32_pathtype(<<c1, c2, relative::binary>>) when c1 in @slash and c2 in @slash, do:
+    {:absolute, relative}
+  defp win32_pathtype(<<c, relative::binary>>) when c in @slash, do:
+    {:volumerelative, relative}
+  defp win32_pathtype(<<_letter, ?:, c, relative::binary>>) when c in @slash, do:
+    {:absolute, relative}
+  defp win32_pathtype(<<_letter, ?:, relative::binary>>), do:
+    {:volumerelative, relative}

-  defp win32_pathtype([char, list | rest]) when is_list(list),
-    do: win32_pathtype([char | list ++ rest])
-
-  defp win32_pathtype(<<c1, c2, relative::binary>>) when c1 in @slash and c2 in @slash,
-    do: {:absolute, relative}
-
-  defp win32_pathtype(<<char, relative::binary>>) when char in @slash,
-    do: {:volumerelative, relative}
-
-  defp win32_pathtype(<<_letter, ?:, char, relative::binary>>) when char in @slash,
-    do: {:absolute, relative}
-
-  defp win32_pathtype(<<_letter, ?:, relative::binary>>), do: {:volumerelative, relative}
-
-  defp win32_pathtype([c1, c2 | relative]) when c1 in @slash and c2 in @slash,
-    do: {:absolute, relative}
-
-  defp win32_pathtype([char | relative]) when char in @slash, do: {:volumerelative, relative}
-
-  defp win32_pathtype([c1, c2, list | rest]) when is_list(list),
-    do: win32_pathtype([c1, c2 | list ++ rest])
-
-  defp win32_pathtype([_letter, ?:, char | relative]) when char in @slash,
-    do: {:absolute, relative}
-
-  defp win32_pathtype([_letter, ?: | relative]), do: {:volumerelative, relative}
-  defp win32_pathtype(relative), do: {:relative, relative}
+  defp win32_pathtype([c1, c2 | relative]) when c1 in @slash and c2 in @slash, do:
+    {:absolute, relative}
+  defp win32_pathtype([c | relative]) when c in @slash, do:
+    {:volumerelative, relative}
+  defp win32_pathtype([c1, c2, list|rest]) when is_list(list), do:
+    win32_pathtype([c1, c2|list++rest])
+  defp win32_pathtype([_letter, ?:, c | relative]) when c in @slash, do:
+    {:absolute, relative}
+  defp win32_pathtype([_letter, ?: | relative]), do:
+    {:volumerelative, relative}
+  defp win32_pathtype(relative), do:
+    {:relative, relative}

  @doc """
  Returns the given `path` relative to the given `from` path.
-
-  In other words, this function tries to strip the `from` prefix from `path`.
+  In other words, it tries to strip the `from` prefix from `path`.

  This function does not query the file system, so it assumes
  no symlinks between the paths.
@@ -313,11 +290,11 @@ defmodule Path do
    relative_to(split(path), split(from), path)
  end

-  defp relative_to([h | t1], [h | t2], original) do
+  defp relative_to([h|t1], [h|t2], original) do
    relative_to(t1, t2, original)
  end

-  defp relative_to([_ | _] = l1, [], _original) do
+  defp relative_to([_|_] = l1, [], _original) do
    join(l1)
  end

@@ -327,14 +304,12 @@ defmodule Path do

  @doc """
  Convenience to get the path relative to the current working
-  directory.
-
-  If, for some reason, the current working directory
-  cannot be retrieved, this function returns the given `path`.
+  directory. If, for some reason, the current working directory
+  cannot be retrieved, returns the full path.
  """
  @spec relative_to_cwd(t) :: binary
  def relative_to_cwd(path) do
-    case :file.get_cwd() do
+    case :file.get_cwd do
      {:ok, base} -> relative_to(path, IO.chardata_to_string(base))
      _ -> path
    end
@@ -358,15 +333,13 @@ defmodule Path do
  """
  @spec basename(t) :: binary
  def basename(path) do
-    :filename.basename(IO.chardata_to_string(path))
+    FN.basename(IO.chardata_to_string(path))
  end

  @doc """
  Returns the last component of `path` with the `extension`
-  stripped.
-
-  This function should be used to remove a specific
-  extension which may or may not be there.
+  stripped. This function should be used to remove a specific
+  extension which may, or may not, be there.

  ## Examples

@@ -382,7 +355,7 @@ defmodule Path do
  """
  @spec basename(t, t) :: binary
  def basename(path, extension) do
-    :filename.basename(IO.chardata_to_string(path), IO.chardata_to_string(extension))
+    FN.basename(IO.chardata_to_string(path), IO.chardata_to_string(extension))
  end

  @doc """
@@ -390,19 +363,15 @@ defmodule Path do

  ## Examples

-      iex> Path.dirname("/foo/bar.ex")
-      "/foo"
-
-      iex> Path.dirname("/foo/bar/baz.ex")
-      "/foo/bar"
-
-      iex> Path.dirname("/foo/bar/")
-      "/foo/bar"
+      Path.dirname("/foo/bar.ex")
+      #=> "/foo"
+      Path.dirname("/foo/bar/baz.ex")
+      #=> "/foo/bar"

  """
  @spec dirname(t) :: binary
  def dirname(path) do
-    :filename.dirname(IO.chardata_to_string(path))
+    FN.dirname(IO.chardata_to_string(path))
  end

  @doc """
@@ -419,7 +388,7 @@ defmodule Path do
  """
  @spec extname(t) :: binary
  def extname(path) do
-    :filename.extension(IO.chardata_to_string(path))
+    FN.extension(IO.chardata_to_string(path))
  end

  @doc """
@@ -436,14 +405,12 @@ defmodule Path do
  """
  @spec rootname(t) :: binary
  def rootname(path) do
-    :filename.rootname(IO.chardata_to_string(path))
+    FN.rootname(IO.chardata_to_string(path))
  end

  @doc """
-  Returns the `path` with the `extension` stripped.
-
-  This function should be used to remove a specific extension which may
-  or may not be there.
+  Returns the `path` with the `extension` stripped. This function should be used to
+  remove a specific extension which might, or might not, be there.

  ## Examples

@@ -456,14 +423,14 @@ defmodule Path do
  """
  @spec rootname(t, t) :: binary
  def rootname(path, extension) do
-    :filename.rootname(IO.chardata_to_string(path), IO.chardata_to_string(extension))
+    FN.rootname(IO.chardata_to_string(path), IO.chardata_to_string(extension))
  end

  @doc """
-  Joins a list of paths.
+  Joins a list of strings.

-  This function should be used to convert a list of paths to a path.
-  Note that any trailing slash is removed when joining.
+  This function should be used to convert a list of strings to a path.
+  Note that any trailing slash is removed on join.

  ## Examples

@@ -477,53 +444,39 @@ defmodule Path do
      "/foo/bar"

  """
-  @spec join(nonempty_list(t)) :: binary
-  def join([name1, name2 | rest]), do: join([join(name1, name2) | rest])
-  def join([name]), do: IO.chardata_to_string(name)
+  @spec join([t]) :: binary
+  def join([name1, name2|rest]), do:
+    join([join(name1, name2)|rest])
+  def join([name]), do:
+    name

  @doc """
  Joins two paths.

  The right path will always be expanded to its relative format
-  and any trailing slash will be removed when joining.
+  and any trailing slash is removed on join.

  ## Examples

      iex> Path.join("foo", "bar")
      "foo/bar"

-      iex> Path.join("/foo", "/bar/")
-      "/foo/bar"
-
-  The functions in this module support chardata, so giving a list will
-  treat it as a single entity:
-
-      iex> Path.join("foo", ["bar", "fiz"])
-      "foo/barfiz"
-
-      iex> Path.join(["foo", "bar"], "fiz")
-      "foobar/fiz"
-
  """
  @spec join(t, t) :: binary
  def join(left, right) do
-    left = IO.chardata_to_string(left)
+    left    = IO.chardata_to_string(left)
    os_type = major_os_type()
-    do_join(left, right, os_type) |> remove_dir_sep(os_type)
+    do_join(left, right, os_type) |> remove_dirsep(os_type)
  end

-  defp do_join("", right, os_type), do: relative(right, os_type)
-  defp do_join("/", right, os_type), do: "/" <> relative(right, os_type)
+  defp do_join("", right, os_type),   do: relative(right, os_type)
+  defp do_join("/", right, os_type),  do: "/" <> relative(right, os_type)
+  defp do_join(left, right, os_type), do: remove_dirsep(left, os_type) <> "/" <> relative(right, os_type)

-  defp do_join(left, right, os_type),
-    do: remove_dir_sep(left, os_type) <> "/" <> relative(right, os_type)
-
-  defp remove_dir_sep("", _os_type), do: ""
-  defp remove_dir_sep("/", _os_type), do: "/"
-
-  defp remove_dir_sep(bin, os_type) do
+  defp remove_dirsep("", _os_type), do: ""
+  defp remove_dirsep("/", _os_type), do: "/"
+  defp remove_dirsep(bin, os_type) do
    last = :binary.last(bin)
-
    if last == ?/ or (last == ?\\ and os_type == :win32) do
      binary_part(bin, 0, byte_size(bin) - 1)
    else
@@ -558,7 +511,7 @@ defmodule Path do
  def split(""), do: []

  def split(path) do
-    :filename.split(IO.chardata_to_string(path))
+    FN.split(IO.chardata_to_string(path))
  end

  defmodule Wildcard do
@@ -568,11 +521,15 @@ defmodule Path do
      call({:read_link_info, file})
    end

+    # For compatibility with buggy Erlang 17.1.
+    def read_file_info(file) do
+      call({:read_link_info, file})
+    end
+
    def list_dir(dir) do
-      case call({:list_dir, dir}) do
+      case call({:list_dir, dir})  do
        {:ok, files} ->
          {:ok, for(file <- files, hd(file) != ?., do: file)}
-
        other ->
          other
      end
@@ -589,47 +546,37 @@ defmodule Path do
  end

  @doc """
-  Traverses paths according to the given `glob` expression and returns a
+  Traverses paths according to the given `glob` expression, and returns a
  list of matches.

-  The wildcard looks like an ordinary path, except that the following
-  "wildcard characters" are interpreted in a special way:
+  The wildcard looks like an ordinary path, except that certain
+  "wildcard characters" are interpreted in a special way. The
+  following characters are special:

-    * `?` - matches one character.
+    * `?` - matches one character

    * `*` - matches any number of characters up to the end of the filename, the
-      next dot, or the next slash.
+      next dot, or the next slash

    * `**` - two adjacent `*`'s used as a single pattern will match all
-      files and zero or more directories and subdirectories.
+      files and zero or more directories and subdirectories

-    * `[char1,char2,...]` - matches any of the characters listed; two
-      characters separated by a hyphen will match a range of characters.
-      Do not add spaces before and after the comma as it would then match
-      paths containing the space character itself.
+    * `[char1, char2, ...]` - matches any of the characters listed; two
+      characters separated by a hyphen will match a range of characters

-    * `{item1,item2,...}` - matches one of the alternatives.
-      Do not add spaces before and after the comma as it would then match
-      paths containing the space character itself.
+    * `{item1, item2, ...}` - matches one of the alternatives

  Other characters represent themselves. Only paths that have
  exactly the same character in the same position will match. Note
-  that matching is case-sensitive: `"a"` will not match `"A"`.
+  that matching is case-sensitive; i.e. "a" will not match "A".

  By default, the patterns `*` and `?` do not match files starting
-  with a dot `.`. See the `:match_dot` option in the "Options" section
-  below.
-
-  ## Options
-
-    * `:match_dot` - (boolean) if `false`, the special wildcard characters `*` and `?`
-      will not match files starting with a dot (`.`). If `true`, files starting with
-      a `.` will not be treated specially. Defaults to `false`.
+  with a dot `.` unless `match_dot: true` is given in `opts`.

  ## Examples

  Imagine you have a directory called `projects` with three Elixir projects
-  inside of it: `elixir`, `ex_doc`, and `plug`. You can find all `.beam` files
+  inside of it: `elixir`, `ex_doc` and `dynamo`. You can find all `.beam` files
  inside the `ebin` directory of each project as follows:

      Path.wildcard("projects/*/ebin/**/*.beam")
@@ -639,25 +586,21 @@ defmodule Path do
      Path.wildcard("projects/*/ebin/**/*.{beam,app}")

  """
-  @spec wildcard(t, keyword) :: [binary]
+  @spec wildcard(t, Keyword.t) :: [binary]
  def wildcard(glob, opts \\ []) do
    mod = if Keyword.get(opts, :match_dot), do: :file, else: Path.Wildcard
-
    glob
-    |> chardata_to_list!()
+    |> chardata_to_list()
    |> :filelib.wildcard(mod)
    |> Enum.map(&IO.chardata_to_string/1)
  end

-  defp chardata_to_list!(chardata) do
+  # expand_dot the given path by expanding "..", "." and "~".
+
+  defp chardata_to_list(chardata) do
    case :unicode.characters_to_list(chardata) do
      result when is_list(result) ->
-        if 0 in result do
-          raise ArgumentError,
-                "cannot execute Path.wildcard/2 for path with null byte, got: #{inspect(chardata)}"
-        else
-          result
-        end
+        result

      {:error, encoded, rest} ->
        raise UnicodeConversionError, encoded: encoded, rest: rest, kind: :invalid
@@ -670,42 +613,46 @@ defmodule Path do
  defp expand_home(type) do
    case IO.chardata_to_string(type) do
      "~" <> rest -> resolve_home(rest)
-      rest -> rest
+      rest        -> rest
    end
  end

-  defp resolve_home(""), do: System.user_home!()
+  defp resolve_home(""), do: System.user_home!

  defp resolve_home(rest) do
-    case {rest, major_os_type()} do
+    case {rest, major_os_type} do
      {"\\" <> _, :win32} ->
-        System.user_home!() <> rest
-
+        System.user_home! <> rest
      {"/" <> _, _} ->
-        System.user_home!() <> rest
-
-      _ ->
-        rest
+        System.user_home! <> rest
+      _ -> rest
    end
  end

-  # expand_dot the given path by expanding "..", "." and "~".
-  defp expand_dot(<<"/", rest::binary>>), do: "/" <> do_expand_dot(rest)
-
+  defp expand_dot(<<"/", rest::binary>>),
+    do: "/" <> do_expand_dot(rest)
  defp expand_dot(<<letter, ":/", rest::binary>>) when letter in ?a..?z,
    do: <<letter, ":/">> <> do_expand_dot(rest)
+  defp expand_dot(path),
+    do: do_expand_dot(path)

-  defp expand_dot(path), do: do_expand_dot(path)
+  defp do_expand_dot(path),
+    do: do_expand_dot(:binary.split(path, "/", [:global]), [])

-  defp do_expand_dot(path), do: do_expand_dot(:binary.split(path, "/", [:global]), [])
-  defp do_expand_dot([".." | t], [_, _ | acc]), do: do_expand_dot(t, acc)
-  defp do_expand_dot([".." | t], []), do: do_expand_dot(t, [])
-  defp do_expand_dot(["." | t], acc), do: do_expand_dot(t, acc)
-  defp do_expand_dot([h | t], acc), do: do_expand_dot(t, ["/", h | acc])
-  defp do_expand_dot([], []), do: ""
-  defp do_expand_dot([], ["/" | acc]), do: IO.iodata_to_binary(:lists.reverse(acc))
+  defp do_expand_dot([".."|t], [_, _|acc]),
+    do: do_expand_dot(t, acc)
+  defp do_expand_dot([".."|t], []),
+    do: do_expand_dot(t, [])
+  defp do_expand_dot(["."|t], acc),
+    do: do_expand_dot(t, acc)
+  defp do_expand_dot([h|t], acc),
+    do: do_expand_dot(t, ["/", h|acc])
+  defp do_expand_dot([], []),
+    do: ""
+  defp do_expand_dot([], ["/"|acc]),
+    do: IO.iodata_to_binary(:lists.reverse(acc))

  defp major_os_type do
-    :os.type() |> elem(0)
+    :os.type |> elem(0)
  end
 end
@@ -1,190 +1,44 @@
 defmodule Port do
-  @moduledoc ~S"""
-  Functions for interacting with the external world through ports.
-
-  Ports provide a mechanism to start operating system processes external
-  to the Erlang VM and communicate with them via message passing.
-
-  ## Example
-
-      iex> port = Port.open({:spawn, "cat"}, [:binary])
-      iex> send(port, {self(), {:command, "hello"}})
-      iex> send(port, {self(), {:command, "world"}})
-      iex> flush()
-      {#Port<0.1444>, {:data, "hello"}}
-      {#Port<0.1444>, {:data, "world"}}
-      iex> send(port, {self(), :close})
-      :ok
-      iex> flush()
-      {#Port<0.1464>, :closed}
-      :ok
-
-  In the example above, we have created a new port that executes the
-  program `cat`. `cat` is a program available on UNIX systems that
-  receives data from multiple inputs and concatenates them in the output.
-
-  After the port was created, we sent it two commands in the form of
-  messages using `Kernel.send/2`. The first command has the binary payload
-  of "hello" and the second has "world".
-
-  After sending those two messages, we invoked the IEx helper `flush()`,
-  which printed all messages received from the port, in this case we got
-  "hello" and "world" back. Notice the messages are in binary because we
-  passed the `:binary` option when opening the port in `Port.open/2`. Without
-  such option, it would have yielded a list of bytes.
-
-  Once everything was done, we closed the port.
-
-  Elixir provides many conveniences for working with ports and some drawbacks.
-  We will explore those below.
-
-  ## Message and function APIs
-
-  There are two APIs for working with ports. It can be either asynchronous via
-  message passing, as in the example above, or by calling the functions on this
-  module.
-
-  The messages supported by ports and their counterpart function APIs are
-  listed below:
-
-    * `{pid, {:command, binary}}` - sends the given data to the port.
-      See `command/3`.
-
-    * `{pid, :close}` - closes the port. Unless the port is already closed,
-      the port will reply with `{port, :closed}` message once it has flushed
-      its buffers and effectively closed. See `close/1`.
-
-    * `{pid, {:connect, new_pid}}` - sets the `new_pid` as the new owner of
-      the port. Once a port is opened, the port is linked and connected to the
-      caller process and communication to the port only happens through the
-      connected process. This message makes `new_pid` the new connected processes.
-      Unless the port is dead, the port will reply to the old owner with
-      `{port, :connected}`. See `connect/2`.
-
-  On its turn, the port will send the connected process the following messages:
-
-    * `{port, {:data, data}}` - data sent by the port
-    * `{port, :closed}` - reply to the `{pid, :close}` message
-    * `{port, :connected}` - reply to the `{pid, {:connect, new_pid}}` message
-    * `{:EXIT, port, reason}` - exit signals in case the port crashes. If reason
-      is not `:normal`, this message will only be received if the owner process
-      is trapping exits
-
-  ## Open mechanisms
-
-  The port can be opened through four main mechanisms.
-
-  As a short summary, prefer to using the `:spawn` and `:spawn_executable`
-  options mentioned below. The other two options, `:spawn_driver` and `:fd`
-  are for advanced usage within the VM. Also consider using `System.cmd/3`
-  if all you want is to execute a program and retrieve its return value.
-
-  ### spawn
-
-  The `:spawn` tuple receives a binary that is going to be executed as a
-  full invocation. For example, we can use it to invoke "echo hello" directly:
-
-      iex> port = Port.open({:spawn, "echo hello"}, [:binary])
-      iex> flush()
-      {#Port<0.1444>, {:data, "hello\n"}}
-
-  `:spawn` will retrieve the program name from the argument and traverse your
-  OS `$PATH` environment variable looking for a matching program.
-
-  Although the above is handy, it means it is impossible to invoke an executable
-  that has whitespaces on its name or in any of its arguments. For those reasons,
-  most times it is preferable to execute `:spawn_executable`.
-
-  ### spawn_executable
-
-  Spawn executable is a more restricted and explicit version of spawn. It expects
-  full file paths to the executable you want to execute. If they are in your `$PATH`,
-  they can be retrieved by calling `System.find_executable/1`:
-
-      iex> path = System.find_executable("echo")
-      iex> port = Port.open({:spawn_executable, path}, [:binary, args: ["hello world"]])
-      iex> flush()
-      {#Port<0.1380>, {:data, "hello world\n"}}
-
-  When using `:spawn_executable`, the list of arguments can be passed via
-  the `:args` option as done above. For the full list of options, see the
-  documentation for the Erlang function `:erlang.open_port/2`.
-
-  ### fd
-
-  The `:fd` name option allows developers to access `in` and `out` file
-  descriptors used by the Erlang VM. You would use those only if you are
-  reimplementing core part of the Runtime System, such as the `:user` and
-  `:shell` processes.
-
-  ## Zombie OS processes
-
-  A port can be closed via the `close/1` function or by sending a `{pid, :close}`
-  message. However, if the VM crashes, a long-running program started by the port
-  will have its stdin and stdout channels closed but **it won't be automatically
-  terminated**.
-
-  While most UNIX command line tools will exit once its communication channels
-  are closed, not all command line applications will do so. While we encourage
-  graceful termination by detecting if stdin/stdout has been closed, we do not
-  always have control over how 3rd party software terminates. In those cases,
-  you can wrap the application in a script that checks for stdin. Here is such
-  script in bash:
-
-      #!/bin/sh
-      "$@" &
-      pid=$!
-      while read line ; do
-        :
-      done
-      kill -KILL $pid
-
-  Now instead of:
-
-      Port.open({:spawn_executable, "/path/to/program"},
-                [args: ["a", "b", "c"]])
-
-  You may invoke:
-
-      Port.open({:spawn_executable, "/path/to/wrapper"},
-                [args: ["/path/to/program", "a", "b", "c"]])
-
+  @moduledoc """
+  Functions related to Erlang ports.
  """

-  @type name ::
-          {:spawn, charlist | binary}
-          | {:spawn_driver, charlist | binary}
-          | {:spawn_executable, charlist | atom}
-          | {:fd, non_neg_integer, non_neg_integer}
+  @type name :: {:spawn, char_list | binary} |
+                {:spawn_driver, char_list | binary} |
+                {:spawn_executable, char_list | atom} |
+                {:fd, non_neg_integer, non_neg_integer}

  @doc """
-  Opens a port given a tuple `name` and a list of `options`.
+  Opens an Erlang port given a tuple `name` and a list of `settings`.

-  The module documentation above contains documentation and examples
-  for the supported `name` values, summarized below:
+  ## Name

-    * `{:spawn, command}` - runs an external program. `command` must contain
-      the program name and optionally a list of arguments separated by space.
-      If passing programs or arguments with space in their name, use the next option.
-    * `{:spawn_executable, filename}` - runs the executable given by the absolute
-      file name `filename`. Arguments can be passed via the `:args` option.
-    * `{:spawn_driver, command}` - spawns so-called port drivers.
-    * `{:fd, fd_in, fd_out}` - accesses file descriptors, `fd_in` and `fd_out`
-      opened by the VM.
+  The supported values for `name` are:

-  For more information and the list of options, see `:erlang.open_port/2`.
+    * `{:spawn, command}` - to run an external program. The first space separated
+      word of `command` will be considered as the name of the program to run, so
+      use `{:spawn_executable, command}` to run a program having spaces in its name.
+    * `{:spawn_driver, command}` - similar to `{:spawn, command}`, but to run a
+      loaded driver.
+    * `{:spawn_executable, filename}` - similar to `{:spawn, filename}`, but to run
+      an external executable. With this option, `filename` in its whole is considered
+      the name of the program to execute.
+    * `{:fd, fd_in, fd_out}` - to access file descriptors used by Erlang, `fd_in`
+      being used for standard input, `fd_out` for standard output.
+
+  For more information, see [`:erlang.open_port/2`](http://www.erlang.org/doc/man/erlang.html#open_port-2).

  Inlined by the compiler.
  """
  @spec open(name, list) :: port
-  def open(name, options) do
-    :erlang.open_port(name, options)
+  def open(name, settings) do
+    :erlang.open_port(name, settings)
  end

  @doc """
  Closes the `port`.

-  For more information, see `:erlang.port_close/1`.
+  For more information, see [`:erlang.port_close/1`](http://www.erlang.org/doc/man/erlang.html#port_close-1).

  Inlined by the compiler.
  """
@@ -196,7 +50,7 @@ defmodule Port do
  @doc """
  Sends `data` to the port driver `port`.

-  For more information, see `:erlang.port_command/2`.
+  For more information, see [`:erlang.port_command/2`](http://www.erlang.org/doc/man/erlang.html#port_command-2).

  Inlined by the compiler.
  """
@@ -208,7 +62,7 @@ defmodule Port do
  @doc """
  Associates the `port` identifier with a `pid`.

-  For more information, see `:erlang.port_connect/2`.
+  For more information, see [`:erlang.port_connect/2`](http://www.erlang.org/doc/man/erlang.html#port_connect-2).

  Inlined by the compiler.
  """
@@ -218,85 +72,76 @@ defmodule Port do
  end

  @doc """
-  Returns information about the `port` or `nil` if the port is closed.
+  Sends a synchronous control command to the `port` and returns its reply as a binary.

-  For more information, see `:erlang.port_info/1`.
+  Not all port drivers support this feature.
+
+  For more information, see [`:erlang.port_control/3`](http://www.erlang.org/doc/man/erlang.html#port_control-3).
+
+  Inlined by the compiler.
  """
-  def info(port) do
-    nillify(:erlang.port_info(port))
+  @spec control(port, integer, iodata) :: iodata | binary
+  def control(port, operation, data) do
+    :erlang.port_control(port, operation, data)
  end

  @doc """
-  Returns information about the `port` or `nil` if the port is closed.
+  Makes a synchronous call to the `port` and returns its reply as a term.

-  For more information, see `:erlang.port_info/2`.
+  Not all port drivers support this control feature.
+
+  For more information, see [`:erlang.port_call/3`](http://www.erlang.org/doc/man/erlang.html#port_call-3).
+
+  Inlined by the compiler.
+  """
+  @spec call(port, integer, term) :: term
+  def call(port, operation, data) do
+    :erlang.port_call(port, operation, data)
+  end
+
+  @doc """
+  Returns information about the `port`
+  or `nil` if the port is closed.
+
+  For more information, see [`:erlang.port_info/1`](http://www.erlang.org/doc/man/erlang.html#port_info-1).
+  """
+  def info(port) do
+    nillify :erlang.port_info(port)
+  end
+
+  @doc """
+  Returns information about the `port`
+  or `nil` if the port is closed.
+
+  For more information, see [`:erlang.port_info/2`](http://www.erlang.org/doc/man/erlang.html#port_info-2).
  """
  @spec info(port, atom) :: {atom, term} | nil
  def info(port, spec)

  def info(port, :registered_name) do
    case :erlang.port_info(port, :registered_name) do
-      :undefined -> nil
      [] -> {:registered_name, []}
-      other -> other
+      other -> nillify(other)
    end
  end

  def info(port, item) do
-    nillify(:erlang.port_info(port, item))
+    nillify :erlang.port_info(port, item)
  end

  @doc """
-  Starts monitoring the given `port` from the calling process.
+  Returns a list of the ports for the current node.

-  Once the monitored port process dies, a message is delivered to the
-  monitoring process in the shape of:
-
-      {:DOWN, ref, :port, object, reason}
-
-  where:
-
-    * `ref` is a monitor reference returned by this function;
-    * `object` is either the `port` being monitored (when monitoring by port id)
-    or `{name, node}` (when monitoring by a port name);
-    * `reason` is the exit reason.
-
-  See `:erlang.monitor/2` for more info.
-
-  Inlined by the compiler.
-  """
-  @doc since: "1.6.0"
-  @spec monitor(port | {name :: atom, node :: atom} | name :: atom) :: reference
-  def monitor(port) do
-    :erlang.monitor(:port, port)
-  end
-
-  @doc """
-  Demonitors the monitor identified by the given `reference`.
-
-  If `monitor_ref` is a reference which the calling process
-  obtained by calling `monitor/1`, that monitoring is turned off.
-  If the monitoring is already turned off, nothing happens.
-
-  See `:erlang.demonitor/2` for more info.
-
-  Inlined by the compiler.
-  """
-  @doc since: "1.6.0"
-  @spec demonitor(reference, options :: [:flush | :info]) :: boolean
-  defdelegate demonitor(monitor_ref, options \\ []), to: :erlang
-
-  @doc """
-  Returns a list of all ports in the current node.
+  For more information, see [`:erlang.ports/0`](http://www.erlang.org/doc/man/erlang.html#ports-0).

  Inlined by the compiler.
  """
  @spec list :: [port]
  def list do
-    :erlang.ports()
+    :erlang.ports
  end

  @compile {:inline, nillify: 1}
  defp nillify(:undefined), do: nil
-  defp nillify(other), do: other
+  defp nillify(other),      do: other
 end
@@ -4,7 +4,7 @@ defmodule Process do

  Besides the functions available in this module, the `Kernel` module
  exposes and auto-imports some basic functionality related to processes
-  available through the following functions:
+  available through the functions:

    * `Kernel.spawn/1` and `Kernel.spawn/3`
    * `Kernel.spawn_link/1` and `Kernel.spawn_link/3`
@@ -12,53 +12,42 @@ defmodule Process do
    * `Kernel.self/0`
    * `Kernel.send/2`

-  While this module provides low-level conveniences to work with processes,
-  developers typically use abstractions such as `Agent`, `GenServer`,
-  `Registry`, `Supervisor` and `Task`  for building their systems and
-  resort to this module for gathering information, trapping exits, links
-  and monitoring.
  """

  @doc """
-  Tells whether the given process is alive on the local node.
+  Returns `true` if the process exists and is alive (i.e. it is not exiting
+  and has not exited yet). Otherwise, returns `false`.

-  If the process identified by `pid` is alive (that is, it's not exiting and has
-  not exited yet) than this function returns `true`. Otherwise, it returns
-  `false`.
-
-  `pid` must refer to a process running on the local node or `ArgumentError` is raised.
+  `pid` must refer to a process at the local node.

  Inlined by the compiler.
  """
-
-  @typedoc """
-  A process destination.
-
-  A remote or local PID, a local port, a locally registered name, or a tuple in
-  the form of `{registered_name, node}` for a registered name at another node.
-  """
-  @type dest :: pid | port | registered_name :: atom | {registered_name :: atom, node}
-
  @spec alive?(pid) :: boolean
-  defdelegate alive?(pid), to: :erlang, as: :is_process_alive
+  def alive?(pid) do
+    :erlang.is_process_alive(pid)
+  end

  @doc """
-  Returns all key-value pairs in the process dictionary.
+  Returns all key-values in the dictionary.

  Inlined by the compiler.
  """
-  @spec get() :: [{term, term}]
-  defdelegate get(), to: :erlang
+  @spec get :: [{term, term}]
+  def get do
+    :erlang.get()
+  end

  @doc """
-  Returns the value for the given `key` in the process dictionary,
-  or `default` if `key` is not set.
+  Returns the value for the given `key`.
  """
+  @spec get(term) :: term
  @spec get(term, default :: term) :: term
  def get(key, default \\ nil) do
    case :erlang.get(key) do
-      :undefined -> default
-      value -> value
+      :undefined ->
+        default
+      value ->
+        value
    end
  end

@@ -68,507 +57,319 @@ defmodule Process do
  Inlined by the compiler.
  """
  @spec get_keys() :: [term]
-  defdelegate get_keys(), to: :erlang
+  def get_keys() do
+    :erlang.get_keys()
+  end

  @doc """
-  Returns all keys in the process dictionary that have the given `value`.
+  Returns all keys that have the given `value`.

  Inlined by the compiler.
  """
  @spec get_keys(term) :: [term]
-  defdelegate get_keys(value), to: :erlang
+  def get_keys(value) do
+    :erlang.get_keys(value)
+  end

  @doc """
-  Stores the given `key`-`value` pair in the process dictionary.
-
-  The return value of this function is the value that was previously stored
-  under `key`, or `nil` in case no value was stored under `key`.
-
-  ## Examples
-
-      # Assuming :locale was not set
-      Process.put(:locale, "en")
-      #=> nil
-      Process.put(:locale, "fr")
-      #=> "en"
+  Stores the given key-value in the process dictionary.

+  The return value is the value that was previously stored under the key `key`
+  (or `nil` in case no value was stored under `key`).
  """
  @spec put(term, term) :: term | nil
  def put(key, value) do
-    nillify(:erlang.put(key, value))
+    nillify :erlang.put(key, value)
  end

  @doc """
-  Deletes the given `key` from the process dictionary.
-
-  Returns the value that was under `key` in the process dictionary,
-  or `nil` if `key` was not stored in the process dictionary.
-
-  ## Examples
-
-      Process.put(:comments, ["comment", "other comment"])
-      Process.delete(:comments)
-      #=> ["comment", "other comment"]
-      Process.delete(:comments)
-      #=> nil
-
+  Deletes the given `key` from the dictionary.
  """
  @spec delete(term) :: term | nil
  def delete(key) do
-    nillify(:erlang.erase(key))
+    nillify :erlang.erase(key)
  end

  @doc """
-  Sends an exit signal with the given `reason` to `pid`.
+  Sends an exit signal with the given reason to the pid.

-  The following behaviour applies if `reason` is any term except `:normal`
-  or `:kill`:
+  The following behaviour applies if reason is any term except `:normal` or `:kill`:

-    1. If `pid` is not trapping exits, `pid` will exit with the given
-       `reason`.
+    1. If pid is not trapping exits, pid will exit with the given reason.

-    2. If `pid` is trapping exits, the exit signal is transformed into a
-       message `{:EXIT, from, reason}` and delivered to the message queue
-       of `pid`.
+    2. If pid is trapping exits, the exit signal is transformed into a message
+       `{:EXIT, from, reason}` and delivered to the message queue of pid.

-  If `reason` is the atom `:normal`, `pid` will not exit (unless `pid` is
-  the calling process, in which case it will exit with the reason `:normal`).
-  If it is trapping exits, the exit signal is transformed into a message
-  `{:EXIT, from, :normal}` and delivered to its message queue.
+    3. If reason is the atom `:normal`, pid will not exit (unless it is the calling
+       process's pid, in which case it will exit with the reason `:normal`).
+       If it is trapping exits, the exit signal is transformed into a message
+       `{:EXIT, from, :normal}` and delivered to its message queue.

-  If `reason` is the atom `:kill`, that is if `Process.exit(pid, :kill)` is called,
-  an untrappable exit signal is sent to `pid` which will unconditionally exit
-  with reason `:killed`.
+    4. If reason is the atom `:kill`, that is if `exit(pid, :kill)` is called,
+       an untrappable exit signal is sent to pid which will unconditionally
+       exit with exit reason `:killed`.

  Inlined by the compiler.

  ## Examples

      Process.exit(pid, :kill)
-      #=> true

  """
  @spec exit(pid, term) :: true
-  defdelegate exit(pid, reason), to: :erlang
-
-  @doc """
-  Sleeps the current process for the given `timeout`.
-
-  `timeout` is either the number of milliseconds to sleep as an
-  integer or the atom `:infinity`. When `:infinity` is given,
-  the current process will sleep forever, and not
-  consume or reply to messages.
-
-  **Use this function with extreme care**. For almost all situations
-  where you would use `sleep/1` in Elixir, there is likely a
-  more correct, faster and precise way of achieving the same with
-  message passing.
-
-  For example, if you are waiting for a process to perform some
-  action, it is better to communicate the progress of such action
-  with messages.
-
-  In other words, **do not**:
-
-      Task.start_link fn ->
-        do_something()
-        ...
-      end
-
-      # Wait until work is done
-      Process.sleep(2000)
-
-  But **do**:
-
-      parent = self()
-      Task.start_link fn ->
-        do_something()
-        send parent, :work_is_done
-        ...
-      end
-
-      receive do
-        :work_is_done -> :ok
-      after
-        30_000 -> :timeout # Optional timeout
-      end
-
-  For cases like the one above, `Task.async/1` and `Task.await/2` are
-  preferred.
-
-  Similarly, if you are waiting for a process to terminate,
-  monitor that process instead of sleeping. **Do not**:
-
-      Task.start_link fn ->
-        ...
-      end
-
-      # Wait until task terminates
-      Process.sleep(2000)
-
-  Instead **do**:
-
-      {:ok, pid} =
-        Task.start_link fn ->
-          ...
-        end
-
-      ref = Process.monitor(pid)
-      receive do
-        {:DOWN, ^ref, _, _, _} -> :task_is_down
-      after
-        30_000 -> :timeout # Optional timeout
-      end
-
-  """
-  @spec sleep(timeout) :: :ok
-  def sleep(timeout)
-      when is_integer(timeout) and timeout >= 0
-      when timeout == :infinity do
-    receive after: (timeout -> :ok)
+  def exit(pid, reason) do
+    :erlang.exit(pid, reason)
  end

  @doc """
-  Sends a message to the given `dest`.
+  Sends a message to the given process.

-  `dest` may be a remote or local PID, a local port, a locally
-  registered name, or a tuple in the form of `{registered_name, node}` for a
-  registered name at another node.
+  If the option `:noconnect` is used and sending the message would require an
+  auto-connection to another node the message is not sent and `:noconnect` is
+  returned.

-  Inlined by the compiler.
-
-  ## Options
-
-    * `:noconnect` - when used, if sending the message would require an
-      auto-connection to another node the message is not sent and `:noconnect` is
-      returned.
-
-    * `:nosuspend` - when used, if sending the message would cause the sender to
-      be suspended the message is not sent and `:nosuspend` is returned.
+  If the option `:nosuspend` is used and sending the message would cause the
+  sender to be suspended the message is not sent and `:nosuspend` is returned.

  Otherwise the message is sent and `:ok` is returned.

  ## Examples

-      iex> Process.send({:name, :node_that_does_not_exist}, :hi, [:noconnect])
+      iex> Process.send({:name, :node_does_not_exist}, :hi, [:noconnect])
      :noconnect

  """
-  @spec send(dest, msg, [option]) :: :ok | :noconnect | :nosuspend
-        when dest: dest(),
-             msg: any,
-             option: :noconnect | :nosuspend
-  defdelegate send(dest, msg, options), to: :erlang
+  @spec send(dest, msg, [option]) :: :ok | :noconnect | :nosuspend when
+        dest: pid | port | atom | {atom, node},
+        msg: any,
+        option: :noconnect | :nosuspend
+  def send(dest, msg, options) do
+    :erlang.send(dest, msg, options)
+  end

  @doc """
  Sends `msg` to `dest` after `time` milliseconds.

-  If `dest` is a PID, it must be the PID of a local process, dead or alive.
+  If `dest` is a pid, it must be the pid of a local process, dead or alive.
  If `dest` is an atom, it must be the name of a registered process
-  which is looked up at the time of delivery. No error is produced if the name does
+  which is looked up at the time of delivery. No error is given if the name does
  not refer to a process.

-  This function returns a timer reference, which can be read with `read_timer/1`
-  or canceled with `cancel_timer/1`.
+  This function returns a timer reference, which can be read or canceled with
+  `read_timer/1` and `cancel_timer/1`.

-  The timer will be automatically canceled if the given `dest` is a PID
-  which is not alive or when the given PID exits. Note that timers will not be
+  Finally, the timer will be automatically canceled if the given `dest` is a pid
+  which is not alive or when the given pid exits. Note that timers will not be
  automatically canceled when `dest` is an atom (as the atom resolution is done
  on delivery).
-
-  Inlined by the compiler.
-
-  ## Options
-
-    * `:abs` - (boolean) when `false`, `time` is treated as relative to the
-    current monotonic time. When `true`, `time` is the absolute value of the
-    Erlang monotonic time at which `msg` should be delivered to `dest`.
-    To read more about Erlang monotonic time and other time-related concepts,
-    look at the documentation for the `System` module. Defaults to `false`.
-
-  ## Examples
-
-      timer_ref = Process.send_after(pid, :hi, 1000)
-
  """
-  @spec send_after(pid | atom, term, non_neg_integer, [option]) :: reference
-        when option: {:abs, boolean}
-  def send_after(dest, msg, time, opts \\ []) do
-    :erlang.send_after(time, dest, msg, opts)
+  @spec send_after(pid | atom, term, non_neg_integer) :: reference
+  def send_after(dest, msg, time) do
+    :erlang.send_after(time, dest, msg)
  end

  @doc """
-  Cancels a timer returned by `send_after/3`.
+  Cancels a timer created by `send_after/3`.

-  When the result is an integer, it represents the time in milliseconds
-  left until the timer would have expired.
+  When the result is an integer, it represents the time in milli-seconds
+  left until the timer will expire.

-  When the result is `false`, a timer corresponding to `timer_ref` could not be
-  found. This can happen either because the timer expired, because it has
-  already been canceled, or because `timer_ref` never corresponded to a timer.
+  When the result is `false`, a timer corresponding to `timer_ref` could
+  not be found. This can be either because the timer expired, already has
+  been canceled, or because `timer_ref` never corresponded to a timer.

-  Even if the timer had expired and the message was sent, this function does not
-  tell you if the timeout message has arrived at its destination yet.
+  If the timer has expired, the timeout message has been sent, but it does
+  not tell you whether or not it has arrived at its destination yet.

  Inlined by the compiler.
-
-  ## Options
-
-    * `:async` - (boolean) when `false`, the request for cancellation is
-      synchronous. When `true`, the request for cancellation is asynchronous,
-      meaning that the request to cancel the timer is issued and `:ok` is
-      returned right away. Defaults to `false`.
-
-    * `:info` - (boolean) whether to return information about the timer being
-      cancelled. When the `:async` option is `false` and `:info` is `true`, then
-      either an integer or `false` (like described above) is returned. If
-      `:async` is `false` and `:info` is `false`, `:ok` is returned. If `:async`
-      is `true` and `:info` is `true`, a message in the form `{:cancel_timer,
-      timer_ref, result}` (where `result` is an integer or `false` like
-      described above) is sent to the caller of this function when the
-      cancellation has been performed. If `:async` is `true` and `:info` is
-      `false`, no message is sent. Defaults to `true`.
-
  """
-  @spec cancel_timer(reference, options) :: non_neg_integer | false | :ok
-        when options: [async: boolean, info: boolean]
-  defdelegate cancel_timer(timer_ref, options \\ []), to: :erlang
+  @spec cancel_timer(reference) :: non_neg_integer | false
+  def cancel_timer(timer_ref) do
+    :erlang.cancel_timer(timer_ref)
+  end

  @doc """
  Reads a timer created by `send_after/3`.

-  When the result is an integer, it represents the time in milliseconds
+  When the result is an integer, it represents the time in milli-seconds
  left until the timer will expire.

-  When the result is `false`, a timer corresponding to `timer_ref` could not be
-  found. This can be either because the timer expired, because it has already
+  When the result is `false`, a timer corresponding to `timer_ref` could
+  not be found. This can be either because the timer expired, already has
  been canceled, or because `timer_ref` never corresponded to a timer.

-  Even if the timer had expired and the message was sent, this function does not
-  tell you if the timeout message has arrived at its destination yet.
+  If the timer has expired, the timeout message has been sent, but it does
+  not tell you whether or not it has arrived at its destination yet.

  Inlined by the compiler.
  """
  @spec read_timer(reference) :: non_neg_integer | false
-  defdelegate read_timer(timer_ref), to: :erlang
+  def read_timer(timer_ref) do
+    :erlang.read_timer(timer_ref)
+  end

-  @type spawn_opt ::
-          :link
-          | :monitor
-          | {:priority, :low | :normal | :high}
-          | {:fullsweep_after, non_neg_integer}
-          | {:min_heap_size, non_neg_integer}
-          | {:min_bin_vheap_size, non_neg_integer}
+  @type spawn_opt  :: :link | :monitor | {:priority, :low | :normal | :high} |
+                      {:fullsweep_after, non_neg_integer} |
+                      {:min_heap_size, non_neg_integer} |
+                      {:min_bin_vheap_size, non_neg_integer}
  @type spawn_opts :: [spawn_opt]

  @doc """
-  Spawns the given function according to the given options.
-
-  The result depends on the given options. In particular,
-  if `:monitor` is given as an option, it will return a tuple
-  containing the PID and the monitoring reference, otherwise
-  just the spawned process PID.
-
-  More options are available; for the comprehensive list of available options
-  check `:erlang.spawn_opt/4`.
-
-  Inlined by the compiler.
-  """
-  @spec spawn((() -> any), spawn_opts) :: pid | {pid, reference}
-  defdelegate spawn(fun, opts), to: :erlang, as: :spawn_opt
-
-  @doc """
-  Spawns the given function `fun` from module `mod`, passing the given `args`
+  Spawns the given module and function passing the given args
  according to the given options.

  The result depends on the given options. In particular,
  if `:monitor` is given as an option, it will return a tuple
-  containing the PID and the monitoring reference, otherwise
-  just the spawned process PID.
+  containing the pid and the monitoring reference, otherwise
+  just the spawned process pid.

  It also accepts extra options, for the list of available options
-  check `:erlang.spawn_opt/4`.
+  check [`:erlang.spawn_opt/4`](http://www.erlang.org/doc/man/erlang.html#spawn_opt-4).
+
+  Inlined by the compiler.
+  """
+  @spec spawn((() -> any), spawn_opts) :: pid | {pid, reference}
+  def spawn(fun, opts) do
+    :erlang.spawn_opt(fun, opts)
+  end
+
+  @doc """
+  Spawns the given module and function passing the given args
+  according to the given options.
+
+  The result depends on the given options. In particular,
+  if `:monitor` is given as an option, it will return a tuple
+  containing the pid and the monitoring reference, otherwise
+  just the spawned process pid.
+
+  It also accepts extra options, for the list of available options
+  check [`:erlang.spawn_opt/4`](http://www.erlang.org/doc/man/erlang.html#spawn_opt-4).

  Inlined by the compiler.
  """
  @spec spawn(module, atom, list, spawn_opts) :: pid | {pid, reference}
-  defdelegate spawn(mod, fun, args, opts), to: :erlang, as: :spawn_opt
+  def spawn(mod, fun, args, opts) do
+    :erlang.spawn_opt(mod, fun, args, opts)
+  end

  @doc """
-  Starts monitoring the given `item` from the calling process.
-
-  Once the monitored process dies, a message is delivered to the
-  monitoring process in the shape of:
-
-      {:DOWN, ref, :process, object, reason}
-
-  where:
-
-    * `ref` is a monitor reference returned by this function;
-    * `object` is either a `pid` of the monitored process (if monitoring
-      a PID) or `{name, node}` (if monitoring a remote or local name);
-    * `reason` is the exit reason.
-
-  If the process is already dead when calling `Process.monitor/1`, a
-  `:DOWN` message is delivered immediately.
+  The calling process starts monitoring the item given.
+  It returns the monitor reference.

  See [the need for monitoring](http://elixir-lang.org/getting-started/mix-otp/genserver.html#the-need-for-monitoring)
-  for an example. See `:erlang.monitor/2` for more info.
+  for an example.
+  See [`:erlang.monitor/2`](http://www.erlang.org/doc/man/erlang.html#monitor-2) for more info.

  Inlined by the compiler.
  """
-  @spec monitor(pid | {name :: atom, node :: atom} | name :: atom) :: reference
+  @spec monitor(pid | {reg_name :: atom, node :: atom} | reg_name :: atom) :: reference
  def monitor(item) do
    :erlang.monitor(:process, item)
  end

  @doc """
-  Demonitors the monitor identified by the given `reference`.
-
  If `monitor_ref` is a reference which the calling process
-  obtained by calling `monitor/1`, that monitoring is turned off.
+  obtained by calling `monitor/1`, this monitoring is turned off.
  If the monitoring is already turned off, nothing happens.

-  See `:erlang.demonitor/2` for more info.
+  See [`:erlang.demonitor/2`](http://www.erlang.org/doc/man/erlang.html#demonitor-2) for more info.

  Inlined by the compiler.
  """
+  @spec demonitor(reference) :: true
  @spec demonitor(reference, options :: [:flush | :info]) :: boolean
-  defdelegate demonitor(monitor_ref, options \\ []), to: :erlang
+  def demonitor(monitor_ref, options \\ []) do
+    :erlang.demonitor(monitor_ref, options)
+  end

  @doc """
-  Returns a list of PIDs corresponding to all the
+  Returns a list of process identifiers corresponding to all the
  processes currently existing on the local node.

-  Note that if a process is exiting, it is considered to exist but not be
-  alive. This means that for such process, `alive?/1` will return `false` but
-  its PID will be part of the list of PIDs returned by this function.
+  Note that a process that is exiting, exists but is not alive, i.e.,
+  `alive?/1` will return `false` for a process that is exiting,
+  but its process identifier will be part of the result returned.

-  See `:erlang.processes/0` for more info.
-
-  Inlined by the compiler.
+  See [`:erlang.processes/0`](http://www.erlang.org/doc/man/erlang.html#processes-0) for more info.
  """
-  @spec list() :: [pid]
-  defdelegate list(), to: :erlang, as: :processes
+  @spec list :: [pid]
+  def list do
+    :erlang.processes()
+  end

  @doc """
-  Creates a link between the calling process and the given item (process or
-  port).
+  Creates a link between the calling process and another process
+  (or port) `pid`, if there is not such a link already.

-  Links are bidirectional. Linked processes can be unlinked by using `unlink/1`.
-
-  If such a link exists already, this function does nothing since there can only
-  be one link between two given processes. If a process tries to create a link
-  to itself, nothing will happen.
-
-  When two processes are linked, each one receives exit signals from the other
-  (see also `exit/2`). Let's assume `pid1` and `pid2` are linked. If `pid2`
-  exits with a reason other than `:normal` (which is also the exit reason used
-  when a process finishes its job) and `pid1` is not trapping exits (see
-  `flag/2`), then `pid1` will exit with the same reason as `pid2` and in turn
-  emit an exit signal to all its other linked processes. The behaviour when
-  `pid1` is trapping exits is described in `exit/2`.
-
-  See `:erlang.link/1` for more info.
+  See [`:erlang.link/1`](http://www.erlang.org/doc/man/erlang.html#link-1) for more info.

  Inlined by the compiler.
  """
  @spec link(pid | port) :: true
-  defdelegate link(pid_or_port), to: :erlang
+  def link(pid) do
+    :erlang.link(pid)
+  end

  @doc """
-  Removes the link between the calling process and the given item (process or
-  port).
+  Removes the link, if there is one, between the calling process and
+  the process or port referred to by `pid`. Returns `true` and does not
+  fail, even if there is no link or `id` does not exist

-  If there is no such link, this function does nothing. If `pid_or_port` does
-  not exist, this function does not produce any errors and simply does nothing.
-
-  The return value of this function is always `true`.
-
-  See `:erlang.unlink/1` for more info.
+  See [`:erlang.unlink/1`](http://www.erlang.org/doc/man/erlang.html#unlink-1) for more info.

  Inlined by the compiler.
  """
  @spec unlink(pid | port) :: true
-  defdelegate unlink(pid_or_port), to: :erlang
-
-  @doc """
-  Registers the given `pid_or_port` under the given `name`.
-
-  `name` must be an atom and can then be used instead of the
-  PID/port identifier when sending messages with `Kernel.send/2`.
-
-  `register/2` will fail with `ArgumentError` in any of the following cases:
-
-    * the PID/Port is not existing locally and alive
-    * the name is already registered
-    * the `pid_or_port` is already registered under a different `name`
-
-  The following names are reserved and cannot be assigned to
-  processes nor ports:
-
-    * `nil`
-    * `false`
-    * `true`
-    * `:undefined`
-
-  """
-  @spec register(pid | port, atom) :: true
-  def register(pid_or_port, name)
-      when is_atom(name) and name not in [nil, false, true, :undefined] do
-    :erlang.register(name, pid_or_port)
-  catch
-    :error, :badarg when node(pid_or_port) != node() ->
-      message = "could not register #{inspect(pid_or_port)} because it belongs to another node"
-      :erlang.error(ArgumentError.exception(message), [pid_or_port, name])
-
-    :error, :badarg ->
-      message =
-        "could not register #{inspect(pid_or_port)} with " <>
-          "name #{inspect(name)} because it is not alive, the name is already " <>
-          "taken, or it has already been given another name"
-
-      :erlang.error(ArgumentError.exception(message), [pid_or_port, name])
+  def unlink(pid) do
+    :erlang.unlink(pid)
  end

  @doc """
-  Removes the registered `name`, associated with a PID
-  or a port identifier.
+  Associates the name with a pid or a port identifier. `name`, which must
+  be an atom, can be used instead of the pid / port identifier with the
+  `Kernel.send/2` function.

-  Fails with `ArgumentError` if the name is not registered
-  to any PID or port.
-
-  Inlined by the compiler.
+  `Process.register/2` will fail with `ArgumentError` if the pid supplied
+  is no longer alive, (check with `alive?/1`) or if the name is
+  already registered (check with `whereis/1`).
  """
-  @spec unregister(atom) :: true
-  defdelegate unregister(name), to: :erlang
+  @spec register(pid | port, atom) :: true
+  def register(pid, name) when not name in [nil, false, true] do
+    :erlang.register(name, pid)
+  end

  @doc """
-  Returns the PID or port identifier registered under `name` or `nil` if the
-  name is not registered.
+  Removes the registered name, associated with a pid or a port identifier.

-  See `:erlang.whereis/1` for more info.
+  See [`:erlang.unregister/1`](http://www.erlang.org/doc/man/erlang.html#unregister-1) for more info.
+  """
+  @spec unregister(atom) :: true
+  def unregister(name) do
+    :erlang.unregister(name)
+  end
+
+  @doc """
+  Returns the pid or port identifier with the registered name.
+  Returns `nil` if the name is not registered.
+
+  See [`:erlang.whereis/1`](http://www.erlang.org/doc/man/erlang.html#whereis-1) for more info.
  """
  @spec whereis(atom) :: pid | port | nil
  def whereis(name) do
-    nillify(:erlang.whereis(name))
+    nillify :erlang.whereis(name)
  end

  @doc """
-  Returns the PID of the group leader for the calling process.
-
-  Inlined by the compiler.
+  Returns the pid of the group leader for the process which evaluates the function.
  """
-  @spec group_leader() :: pid
-  defdelegate group_leader(), to: :erlang
+  @spec group_leader :: pid
+  def group_leader do
+    :erlang.group_leader
+  end

  @doc """
-  Sets the group leader of the given `pid` to `leader`.
-
-  Typically, this is used when a process started from a certain shell should
-  have a group leader other than `:init`.
-
-  Inlined by the compiler.
+  Sets the group leader of `pid` to `leader`. Typically, this is used when a processes
+  started from a certain shell should have a group leader other than `:init`.
  """
  @spec group_leader(pid, leader :: pid) :: true
  def group_leader(pid, leader) do
@@ -577,77 +378,57 @@ defmodule Process do

  @doc """
  Returns a list of names which have been registered using `register/2`.
-
-  Inlined by the compiler.
  """
-  @spec registered() :: [atom]
-  defdelegate registered(), to: :erlang
-
-  @typep heap_size ::
-           non_neg_integer
-           | %{size: non_neg_integer, kill: boolean, error_logger: boolean}
-
-  @typep priority_level :: :low | :normal | :high | :max
+  @spec registered :: [atom]
+  def registered do
+    :erlang.registered()
+  end

+  @typep process_flag :: :trap_exit | :error_handler | :min_heap_size |
+                         :min_bin_vheap_size | :priority | :save_calls |
+                         :sensitive
  @doc """
-  Sets the given `flag` to `value` for the calling process.
+  Sets certain flags for the process which calls this function.
+  Returns the old value of the flag.

-  Returns the old value of `flag`.
-
-  See `:erlang.process_flag/2` for more info.
-
-  Inlined by the compiler.
+  See [`:erlang.process_flag/2`](http://www.erlang.org/doc/man/erlang.html#process_flag-2) for more info.
  """
-  @spec flag(:error_handler, module) :: module
-  @spec flag(:max_heap_size, heap_size) :: heap_size
-  @spec flag(:message_queue_data, :erlang.message_queue_data()) :: :erlang.message_queue_data()
-  @spec flag(:min_bin_vheap_size, non_neg_integer) :: non_neg_integer
-  @spec flag(:min_heap_size, non_neg_integer) :: non_neg_integer
-  @spec flag(:monitor_nodes, term) :: term
-  @spec flag({:monitor_nodes, term()}, term) :: term
-  @spec flag(:priority, priority_level) :: priority_level
-  @spec flag(:save_calls, 0..10000) :: 0..10000
-  @spec flag(:sensitive, boolean) :: boolean
-  @spec flag(:trap_exit, boolean) :: boolean
-  defdelegate flag(flag, value), to: :erlang, as: :process_flag
-
-  @doc """
-  Sets the given `flag` to `value` for the given process `pid`.
-
-  Returns the old value of `flag`.
-
-  It raises `ArgumentError` if `pid` is not a local process.
-
-  The allowed values for `flag` are only a subset of those allowed in `flag/2`,
-  namely `:save_calls`.
-
-  See `:erlang.process_flag/3` for more info.
-
-  Inlined by the compiler.
-  """
-  @spec flag(pid, :save_calls, 0..10000) :: 0..10000
-  defdelegate flag(pid, flag, value), to: :erlang, as: :process_flag
-
-  @doc """
-  Returns information about the process identified by `pid`, or returns `nil` if the process
-  is not alive.
-
-  Use this only for debugging information.
-
-  See `:erlang.process_info/1` for more info.
-  """
-  @spec info(pid) :: keyword | nil
-  def info(pid) do
-    nillify(:erlang.process_info(pid))
+  @spec flag(process_flag, term) :: term
+  def flag(flag, value) do
+    :erlang.process_flag(flag, value)
  end

  @doc """
-  Returns information about the process identified by `pid`,
-  or returns `nil` if the process is not alive.
+  Sets certain flags for the process `pid`, in the same manner as `flag/2`.
+  Returns the old value of the flag. The allowed values for `flag` are
+  only a subset of those allowed in `flag/2`, namely: `save_calls`.

-  See `:erlang.process_info/2` for more info.
+  See [`:erlang.process_flag/3`](http://www.erlang.org/doc/man/erlang.html#process_flag-3) for more info.
  """
-  @spec info(pid, atom | [atom]) :: {atom, term} | [{atom, term}] | nil
+  @spec flag(pid, :save_calls, non_neg_integer) :: non_neg_integer
+  def flag(pid, flag, value) do
+    :erlang.process_flag(pid, flag, value)
+  end
+
+  @doc """
+  Returns information about the process identified by `pid` or `nil` if the process
+  is not alive.
+  Use this only for debugging information.
+
+  See [`:erlang.process_info/1`](http://www.erlang.org/doc/man/erlang.html#process_info-1) for more info.
+  """
+  @spec info(pid) :: Keyword.t
+  def info(pid) do
+    nillify :erlang.process_info(pid)
+  end
+
+  @doc """
+  Returns information about the process identified by `pid`
+  or `nil` if the process is not alive.
+
+  See [`:erlang.process_info/2`](http://www.erlang.org/doc/man/erlang.html#process_info-2) for more info.
+  """
+  @spec info(pid, atom | [atom]) :: {atom, term} | [{atom, term}]  | nil
  def info(pid, spec)

  def info(pid, :registered_name) do
@@ -659,25 +440,25 @@ defmodule Process do
  end

  def info(pid, spec) when is_atom(spec) or is_list(spec) do
-    nillify(:erlang.process_info(pid, spec))
+    nillify :erlang.process_info(pid, spec)
  end

  @doc """
-  Puts the calling process into a "hibernation" state.
-
-  The calling process is put into a waiting state
+  Puts the calling process into a wait state
  where its memory allocation has been reduced as much as possible,
  which is useful if the process does not expect to receive any messages
  in the near future.

-  See `:erlang.hibernate/3` for more info.
+  See [`:erlang.hibernate/3`](http://www.erlang.org/doc/man/erlang.html#hibernate-3) for more info.

  Inlined by the compiler.
  """
  @spec hibernate(module, atom, list) :: no_return
-  defdelegate hibernate(mod, fun_name, args), to: :erlang
+  def hibernate(mod, fun, args) do
+    :erlang.hibernate(mod, fun, args)
+  end

  @compile {:inline, nillify: 1}
  defp nillify(:undefined), do: nil
-  defp nillify(other), do: other
+  defp nillify(other),      do: other
 end
@@ -19,44 +19,44 @@ defmodule Protocol do
  defmacro def({name, _, args}) when is_atom(name) and is_list(args) do
    arity = length(args)

-    type_args = :lists.map(fn _ -> quote(do: term) end, :lists.seq(2, arity))
+    type_args = :lists.map(fn _ -> quote(do: term) end,
+                           :lists.seq(2, arity))
    type_args = [quote(do: t) | type_args]

-    varify = fn pos -> Macro.var(String.to_atom("var" <> Integer.to_string(pos)), __MODULE__) end
-
-    call_args = :lists.map(varify, :lists.seq(2, arity))
-    call_args = [quote(do: term) | call_args]
+    call_args = :lists.map(fn i -> {String.to_atom(<<?x, i + 64>>), [], __MODULE__} end,
+                           :lists.seq(2, arity))
+    call_args = [quote(do: t) | call_args]

    quote do
-      name = unquote(name)
+      name  = unquote(name)
      arity = unquote(arity)

-      @functions [{name, arity} | @functions]
+      @functions [{name, arity}|@functions]

      # Generate a fake definition with the user
      # signature that will be used by docs
-      Kernel.def(unquote(name)(unquote_splicing(args)))
+      Kernel.def unquote(name)(unquote_splicing(args))

      # Generate the actual implementation
      Kernel.def unquote(name)(unquote_splicing(call_args)) do
-        impl_for!(term).unquote(name)(unquote_splicing(call_args))
+        impl_for!(t).unquote(name)(unquote_splicing(call_args))
      end

      # Convert the spec to callback if possible,
      # otherwise generate a dummy callback
-      Module.spec_to_callback(__MODULE__, {name, arity}) ||
+      Protocol.__spec__?(__MODULE__, name, arity) ||
        @callback unquote(name)(unquote_splicing(type_args)) :: term
    end
  end

  defmacro def(_) do
-    raise ArgumentError, "invalid arguments for def inside defprotocol"
+    raise ArgumentError, "invalid args for def inside defprotocol"
  end

  @doc """
  Checks if the given module is loaded and is protocol.

-  Returns `:ok` if so, otherwise raises `ArgumentError`.
+  Returns `:ok` if so, otherwise raises ArgumentError.
  """
  @spec assert_protocol!(module) :: :ok | no_return
  def assert_protocol!(module) do
@@ -66,14 +66,14 @@ defmodule Protocol do
  defp assert_protocol!(module, extra) do
    case Code.ensure_compiled(module) do
      {:module, ^module} -> :ok
-      _ -> raise ArgumentError, "#{inspect(module)} is not available" <> extra
+      _ -> raise ArgumentError, "#{inspect module} is not available" <> extra
    end

    try do
      module.__protocol__(:module)
    rescue
      UndefinedFunctionError ->
-        raise ArgumentError, "#{inspect(module)} is not a protocol" <> extra
+        raise ArgumentError, "#{inspect module} is not a protocol" <> extra
    end

    :ok
@@ -83,7 +83,7 @@ defmodule Protocol do
  Checks if the given module is loaded and is an implementation
  of the given protocol.

-  Returns `:ok` if so, otherwise raises `ArgumentError`.
+  Returns `:ok` if so, otherwise raises ArgumentError.
  """
  @spec assert_impl!(module, module) :: :ok | no_return
  def assert_impl!(protocol, base) do
@@ -95,76 +95,27 @@ defmodule Protocol do

    case Code.ensure_compiled(impl) do
      {:module, ^impl} -> :ok
-      _ -> raise ArgumentError, "#{inspect(impl)} is not available" <> extra
+      _ -> raise ArgumentError,
+             "#{inspect impl} is not available" <> extra
    end

    try do
      impl.__impl__(:protocol)
    rescue
      UndefinedFunctionError ->
-        raise ArgumentError, "#{inspect(impl)} is not an implementation of a protocol" <> extra
+        raise ArgumentError,
+          "#{inspect impl} is not an implementation of a protocol" <> extra
    else
      ^protocol ->
        :ok
-
      other ->
        raise ArgumentError,
-              "expected #{inspect(impl)} to be an implementation of #{inspect(protocol)}" <>
-                ", got: #{inspect(other)}" <> extra
+          "expected #{inspect impl} to be an implementation of #{inspect protocol}, got: #{inspect other}" <> extra
    end
  end

  @doc """
  Derives the `protocol` for `module` with the given options.
-
-  If your implementation passes options or if you are generating
-  custom code based on the struct, you will also need to implement
-  a macro defined as `__deriving__(module, struct, options)`
-  to get the options that were passed.
-
-  ## Examples
-
-      defprotocol Derivable do
-        def ok(a)
-      end
-
-      defimpl Derivable, for: Any do
-        defmacro __deriving__(module, struct, options) do
-          quote do
-            defimpl Derivable, for: unquote(module) do
-              def ok(arg) do
-                {:ok, arg, unquote(Macro.escape(struct)), unquote(options)}
-              end
-            end
-          end
-        end
-
-        def ok(arg) do
-          {:ok, arg}
-        end
-      end
-
-      defmodule ImplStruct do
-        @derive [Derivable]
-        defstruct a: 0, b: 0
-
-        defimpl Sample do
-          def ok(struct) do
-            Unknown.undefined(struct)
-          end
-        end
-      end
-
-  Explicit derivations can now be called via `__deriving__`:
-
-      # Explicitly derived via `__deriving__`
-      Derivable.ok(%ImplStruct{a: 1, b: 1})
-
-      # Explicitly derived by API via `__deriving__`
-      require Protocol
-      Protocol.derive(Derivable, ImplStruct, :oops)
-      Derivable.ok(%ImplStruct{a: 1, b: 1})
-
  """
  defmacro derive(protocol, module, options \\ []) do
    quote do
@@ -178,8 +129,8 @@ defmodule Protocol do
  @doc """
  Extracts all protocols from the given paths.

-  The paths can be either a charlist or a string. Internally
-  they are worked on as charlists, so passing them as lists
+  The paths can be either a char list or a string. Internally
+  they are worked on as char lists, so passing them as lists
  avoid extra conversion.

  Does not load any of the protocols.
@@ -193,22 +144,23 @@ defmodule Protocol do
      true

  """
-  @spec extract_protocols([charlist | String.t()]) :: [atom]
+  @spec extract_protocols([char_list | String.t]) :: [atom]
  def extract_protocols(paths) do
-    extract_matching_by_attribute(paths, 'Elixir.', fn module, attributes ->
-      case attributes[:protocol] do
-        [fallback_to_any: _] -> module
-        _ -> nil
+    extract_matching_by_attribute paths, 'Elixir.',
+      fn module, attributes ->
+        case attributes[:protocol] do
+          [fallback_to_any: _] -> module
+          _ -> nil
+        end
      end
-    end)
  end

  @doc """
  Extracts all types implemented for the given protocol from
  the given paths.

-  The paths can be either a charlist or a string. Internally
-  they are worked on as charlists, so passing them as lists
+  The paths can be either a char list or a string. Internally
+  they are worked on as char lists, so passing them as lists
  avoid extra conversion.

  Does not load any of the implementations.
@@ -222,23 +174,23 @@ defmodule Protocol do
      true

  """
-  @spec extract_impls(module, [charlist | String.t()]) :: [atom]
+  @spec extract_impls(module, [char_list | String.t]) :: [atom]
  def extract_impls(protocol, paths) when is_atom(protocol) do
-    prefix = Atom.to_charlist(protocol) ++ '.'
-
-    extract_matching_by_attribute(paths, prefix, fn _mod, attributes ->
-      case attributes[:protocol_impl] do
-        [protocol: ^protocol, for: for] -> for
-        _ -> nil
-      end
-    end)
+    prefix = Atom.to_char_list(protocol) ++ '.'
+    extract_matching_by_attribute paths, prefix, fn
+      _mod, attributes ->
+        case attributes[:impl] do
+          [protocol: ^protocol, for: for] -> for
+          _ -> nil
+        end
+    end
  end

  defp extract_matching_by_attribute(paths, prefix, callback) do
    for path <- paths,
-        file <- list_dir(path),
-        mod = extract_from_file(path, file, prefix, callback),
-        do: mod
+       file <- list_dir(path),
+       mod = extract_from_file(path, file, prefix, callback),
+       do: mod
  end

  defp list_dir(path) when is_list(path) do
@@ -248,7 +200,7 @@ defmodule Protocol do
    end
  end

-  defp list_dir(path), do: list_dir(to_charlist(path))
+  defp list_dir(path), do: list_dir(to_char_list(path))

  defp extract_from_file(path, file, prefix, callback) do
    if :lists.prefix(prefix, file) and :filename.extension(file) == '.beam' do
@@ -260,9 +212,8 @@ defmodule Protocol do
    case :beam_lib.chunks(file, [:attributes]) do
      {:ok, {module, [attributes: attributes]}} ->
        callback.(module, attributes)
-
-      _ ->
-        nil
+       _ ->
+         nil
    end
  end

@@ -299,39 +250,30 @@ defmodule Protocol do
  it will be loaded.
  """
  @spec consolidate(module, [module]) ::
-          {:ok, binary}
-          | {:error, :not_a_protocol}
-          | {:error, :no_beam_info}
+    {:ok, binary} |
+    {:error, :not_a_protocol} |
+    {:error, :no_beam_info}
  def consolidate(protocol, types) when is_atom(protocol) do
-    with {:ok, ast_info, chunks_info} <- beam_protocol(protocol),
-         {:ok, code} <- change_debug_info(ast_info, types),
-         do: compile(protocol, code, chunks_info)
+    with {:ok, info} <- beam_protocol(protocol),
+         {:ok, code, docs} <- change_debug_info(info, types),
+         do: compile(code, docs)
  end

+  @docs_chunk 'ExDc'
+
  defp beam_protocol(protocol) do
-    chunk_ids = [:abstract_code, :attributes, :compile_info, 'Docs', 'ExDp']
+    chunk_ids = [:abstract_code, :attributes, @docs_chunk]
    opts = [:allow_missing_chunks]
-
    case :beam_lib.chunks(beam_file(protocol), chunk_ids, opts) do
-      {:ok, {^protocol, entries}} ->
-        [
-          {:abstract_code, {_raw, abstract_code}},
-          {:attributes, attributes},
-          {:compile_info, compile_info} | extra_chunks
-        ] = entries
-
-        extra_chunks =
-          for {name, contents} when is_binary(contents) <- extra_chunks,
-              do: {List.to_string(name), contents}
-
+      {:ok, {^protocol, [{:abstract_code, {_raw, abstract_code}},
+                         {:attributes, attributes},
+                         {@docs_chunk, docs}]}} ->
        case attributes[:protocol] do
          [fallback_to_any: any] ->
-            {:ok, {protocol, any, abstract_code}, {compile_info, extra_chunks}}
-
+            {:ok, {protocol, any, abstract_code, docs}}
          _ ->
            {:error, :not_a_protocol}
        end
-
      _ ->
        {:error, :no_beam_info}
    end
@@ -339,155 +281,102 @@ defmodule Protocol do

  defp beam_file(module) when is_atom(module) do
    case :code.which(module) do
-      [_ | _] = file -> file
-      _ -> module
+      atom when is_atom(atom) -> module
+      file -> file
    end
  end

  # Change the debug information to the optimized
  # impl_for/1 dispatch version.
-  defp change_debug_info({protocol, any, code}, types) do
-    types = if any, do: types, else: List.delete(types, Any)
-    all = [Any] ++ for {_guard, mod} <- __builtin__(), do: mod
+  defp change_debug_info({protocol, any, code, docs}, types) do
+    types   = if any, do: types, else: List.delete(types, Any)
+    all     = [Any] ++ for {_guard, mod} <- builtin, do: mod
    structs = types -- all
-
    case change_impl_for(code, protocol, types, structs, false, []) do
-      {:ok, ret} -> {:ok, ret}
-      other -> other
+      {:ok, ret} -> {:ok, ret, docs}
+      other      -> other
    end
  end

-  defp change_impl_for(
-         [{:function, line, :__protocol__, 1, clauses} | tail],
-         protocol,
-         types,
-         structs,
-         _,
-         acc
-       ) do
-    abstract_types = :erl_parse.abstract(:lists.usort(types))
+  defp change_impl_for([{:function, line, :__protocol__, 1, clauses}|t], protocol, types, structs, _, acc) do
+    clauses = :lists.map(fn
+      {:clause, l, [{:atom, _, :consolidated?}], [], [{:atom, _, _}]} ->
+        {:clause, l, [{:atom, 0, :consolidated?}], [], [{:atom, 0, true}]}
+      {:clause, _, _, _, _} = c ->
+        c
+    end, clauses)

-    clauses =
-      Enum.map(clauses, fn
-        {:clause, l, [{:atom, _, :consolidated?}], [], [{:atom, _, _}]} ->
-          {:clause, l, [{:atom, 0, :consolidated?}], [], [{:atom, 0, true}]}
-
-        {:clause, l, [{:atom, _, :impls}], [], [{:atom, _, _}]} ->
-          tuple = {:tuple, 0, [{:atom, 0, :consolidated}, abstract_types]}
-          {:clause, l, [{:atom, 0, :impls}], [], [tuple]}
-
-        {:clause, _, _, _, _} = c ->
-          c
-      end)
-
-    acc = [{:function, line, :__protocol__, 1, clauses} | acc]
-    change_impl_for(tail, protocol, types, structs, true, acc)
+    change_impl_for(t, protocol, types, structs, true,
+                    [{:function, line, :__protocol__, 1, clauses}|acc])
  end

-  defp change_impl_for(
-         [{:function, line, :impl_for, 1, _} | tail],
-         protocol,
-         types,
-         structs,
-         protocol?,
-         acc
-       ) do
+  defp change_impl_for([{:function, line, :impl_for, 1, _}|t], protocol, types, structs, is_protocol, acc) do
    fallback = if Any in types, do: load_impl(protocol, Any)

-    clauses =
-      for {guard, mod} <- __builtin__(),
-          mod in types,
-          do: builtin_clause_for(mod, guard, protocol, line)
+    clauses = for {guard, mod} <- builtin,
+                  mod in types,
+                  do: builtin_clause_for(mod, guard, protocol, line)

-    clauses =
-      [struct_clause_for(line) | clauses] ++ [fallback_clause_for(fallback, protocol, line)]
+    clauses = [struct_clause_for(line)|clauses] ++
+              [fallback_clause_for(fallback, protocol, line)]

-    acc = [{:function, line, :impl_for, 1, clauses} | acc]
-    change_impl_for(tail, protocol, types, structs, protocol?, acc)
+    change_impl_for(t, protocol, types, structs, is_protocol,
+                    [{:function, line, :impl_for, 1, clauses}|acc])
  end

-  defp change_impl_for(
-         [{:function, line, :struct_impl_for, 1, _} | tail],
-         protocol,
-         types,
-         structs,
-         protocol?,
-         acc
-       ) do
+  defp change_impl_for([{:function, line, :struct_impl_for, 1, _}|t], protocol, types, structs, is_protocol, acc) do
    fallback = if Any in types, do: load_impl(protocol, Any)
    clauses = for struct <- structs, do: each_struct_clause_for(struct, protocol, line)
    clauses = clauses ++ [fallback_clause_for(fallback, protocol, line)]

-    acc = [{:function, line, :struct_impl_for, 1, clauses} | acc]
-    change_impl_for(tail, protocol, types, structs, protocol?, acc)
+    change_impl_for(t, protocol, types, structs, is_protocol,
+                    [{:function, line, :struct_impl_for, 1, clauses}|acc])
  end

-  defp change_impl_for(
-         [{:attribute, line, :spec, {{:__protocol__, 1}, funspecs}} | tail],
-         protocol,
-         types,
-         structs,
-         protocol?,
-         acc
-       ) do
-    new_specs =
-      for spec <- funspecs do
-        case spec do
-          {:type, line, :fun, [{:type, _, :product, [{:atom, _, :consolidated?}]}, _]} ->
-            product = {:type, line, :product, [{:atom, 0, :consolidated?}]}
-            {:type, line, :fun, [product, {:atom, 0, true}]}
-
-          {:type, line, :fun, [{:type, _, :product, [{:atom, _, :impls}]}, _]} ->
-            impls = for mod <- types, do: {:atom, 0, mod}
-            list = {:type, 0, :list, [{:type, 0, :union, impls}]}
-            tuple = {:type, 0, :tuple, [{:atom, 0, :consolidated}, list]}
-            {:type, line, :fun, [{:type, line, :product, [{:atom, 0, :impls}]}, tuple]}
-
-          other ->
-            other
-        end
-      end
-
-    acc = [{:attribute, line, :spec, {{:__protocol__, 1}, new_specs}} | acc]
-    change_impl_for(tail, protocol, types, structs, protocol?, acc)
+  defp change_impl_for([h|t], protocol, info, types, is_protocol, acc) do
+    change_impl_for(t, protocol, info, types, is_protocol, [h|acc])
  end

-  defp change_impl_for([head | tail], protocol, info, types, protocol?, acc) do
-    change_impl_for(tail, protocol, info, types, protocol?, [head | acc])
-  end
-
-  defp change_impl_for([], _protocol, _info, _types, protocol?, acc) do
-    if protocol? do
-      {:ok, Enum.reverse(acc)}
+  defp change_impl_for([], protocol, _info, _types, is_protocol, acc) do
+    if is_protocol do
+      {:ok, {protocol, Enum.reverse(acc)}}
    else
      {:error, :not_a_protocol}
    end
  end

  defp builtin_clause_for(mod, guard, protocol, line) do
-    remote = {:remote, line, {:atom, line, :erlang}, {:atom, line, guard}}
-    guard = {:call, line, remote, [{:var, line, :x}]}
-    body = {:atom, line, load_impl(protocol, mod)}
-    {:clause, line, [{:var, line, :x}], [[guard]], [body]}
+    {:clause, line,
+      [{:var, line, :x}],
+      [[{:call, line,
+          {:remote, line, {:atom, line, :erlang}, {:atom, line, guard}},
+          [{:var, line, :x}],
+     }]],
+      [{:atom, line, load_impl(protocol, mod)}]}
  end

  defp struct_clause_for(line) do
-    map_field_exact = {:map_field_exact, line, {:atom, line, :__struct__}, {:var, line, :x}}
-    arg = {:map, line, [map_field_exact]}
-
-    is_atom = {:remote, line, {:atom, line, :erlang}, {:atom, line, :is_atom}}
-    guard = {:call, line, is_atom, [{:var, line, :x}]}
-
-    body = {:call, line, {:atom, line, :struct_impl_for}, [{:var, line, :x}]}
-    {:clause, line, [arg], [[guard]], [body]}
+    {:clause, line,
+      [{:map, line, [
+        {:map_field_exact, line, {:atom, line, :__struct__}, {:var, line, :x}}
+      ]}],
+      [[{:call, line,
+          {:remote, line, {:atom, line, :erlang}, {:atom, line, :is_atom}},
+          [{:var, line, :x}],
+     }]],
+      [{:call, line,
+          {:atom, line, :struct_impl_for},
+          [{:var, line, :x}]}]}
  end

-  defp each_struct_clause_for(struct, protocol, line) do
-    {:clause, line, [{:atom, line, struct}], [], [{:atom, line, load_impl(protocol, struct)}]}
+  defp each_struct_clause_for(other, protocol, line) do
+    {:clause, line, [{:atom, line, other}], [],
+      [{:atom, line, load_impl(protocol, other)}]}
  end

  defp fallback_clause_for(value, _protocol, line) do
-    {:clause, line, [{:var, line, :_}], [], [{:atom, line, value}]}
+    {:clause, line, [{:var, line, :_}], [],
+      [{:atom, line, value}]}
  end

  defp load_impl(protocol, for) do
@@ -495,31 +384,26 @@ defmodule Protocol do
  end

  # Finally compile the module and emit its bytecode.
-  defp compile(protocol, code, {compile_info, extra_chunks}) do
-    opts = Keyword.take(compile_info, [:source])
-    opts = if Code.compiler_options()[:debug_info], do: [:debug_info | opts], else: opts
-    {:ok, ^protocol, binary, _warnings} = :compile.forms(code, [:return | opts])
-    {:ok, :elixir_erl.add_beam_chunks(binary, extra_chunks)}
+  defp compile({protocol, code}, docs) do
+    opts = if Code.compiler_options[:debug_info], do: [:debug_info], else: []
+    {:ok, ^protocol, binary, _warnings} = :compile.forms(code, [:return|opts])
+    unless docs == :missing_chunk do
+      binary = :elixir_module.add_beam_chunk(binary, @docs_chunk, docs)
+    end
+    {:ok, binary}
  end

  ## Definition callbacks

  @doc false
-  def __protocol__(name, do: block) do
+  def __protocol__(name, [do: block]) do
    quote do
      defmodule unquote(name) do
        # We don't allow function definition inside protocols
-        import Kernel,
-          except: [
-            defmacrop: 1,
-            defmacrop: 2,
-            defmacro: 1,
-            defmacro: 2,
-            defp: 1,
-            defp: 2,
-            def: 1,
-            def: 2
-          ]
+        import Kernel, except: [
+          defmacrop: 1, defmacrop: 2, defmacro: 1, defmacro: 2,
+          defp: 1, defp: 2, def: 1, def: 2
+        ]

        # Import the new dsl that holds the new def
        import Protocol, only: [def: 1]
@@ -535,23 +419,15 @@ defmodule Protocol do
        _ = unquote(block)

        # Finalize expansion
-        unquote(after_defprotocol())
+        unquote(after_defprotocol)
      end
    end
  end

  defp after_defprotocol do
-    quote bind_quoted: [builtin: __builtin__()] do
-      any_impl_for =
-        if @fallback_to_any do
-          quote do: unquote(__MODULE__.Any).__impl__(:target)
-        else
-          nil
-        end
-
-      @doc false
-      @spec impl_for(term) :: atom | nil
-      Kernel.def(impl_for(data))
+    quote bind_quoted: [builtin: builtin] do
+      @spec impl_for(term) :: atom() | nil
+      Kernel.def impl_for(data)

      # Define the implementation for structs.
      #
@@ -561,58 +437,49 @@ defmodule Protocol do
        struct_impl_for(struct)
      end

-      # Define the implementation for built-ins
-      :lists.foreach(
-        fn {guard, mod} ->
-          target = Module.concat(__MODULE__, mod)
+      # Define the implementation for builtins.
+      :lists.foreach(fn {guard, mod} ->
+        target = Module.concat(__MODULE__, mod)

-          Kernel.def impl_for(data) when :erlang.unquote(guard)(data) do
-            case Code.ensure_compiled?(unquote(target)) and
-                   function_exported?(unquote(target), :__impl__, 1) do
-              true -> unquote(target).__impl__(:target)
-              false -> unquote(any_impl_for)
-            end
+        Kernel.def impl_for(data) when :erlang.unquote(guard)(data) do
+          case impl_for?(unquote(target)) do
+            true  -> unquote(target).__impl__(:target)
+            false -> any_impl_for
          end
-        end,
-        builtin
-      )
+        end
+      end, builtin)

-      # Define a catch-all impl_for/1 clause to pacify Dialyzer (since
-      # destructuring opaque types is illegal, Dialyzer will think none of the
-      # previous clauses matches opaque types, and without this clause, will
-      # conclude that impl_for can't handle an opaque argument). This is a hack
-      # since it relies on Dialyzer not being smart enough to conclude that all
-      # opaque types will get the any_impl_for/0 implementation.
-      Kernel.def impl_for(_) do
-        unquote(any_impl_for)
+      @spec impl_for!(term) :: atom() | no_return()
+      Kernel.def impl_for!(data) do
+        impl_for(data) || raise(Protocol.UndefinedError, protocol: __MODULE__, value: data)
      end

-      @doc false
-      @spec impl_for!(term) :: atom
-      if any_impl_for do
-        Kernel.def impl_for!(data) do
-          impl_for(data)
-        end
+      # Internal handler for Any
+      if @fallback_to_any do
+        Kernel.defp any_impl_for, do: __MODULE__.Any.__impl__(:target)
      else
-        Kernel.def impl_for!(data) do
-          impl_for(data) || raise(Protocol.UndefinedError, protocol: __MODULE__, value: data)
-        end
+        Kernel.defp any_impl_for, do: nil
      end

      # Internal handler for Structs
      Kernel.defp struct_impl_for(struct) do
        target = Module.concat(__MODULE__, struct)
-
-        case Code.ensure_compiled?(target) and function_exported?(target, :__impl__, 1) do
-          true -> target.__impl__(:target)
-          false -> unquote(any_impl_for)
+        case impl_for?(target) do
+          true  -> target.__impl__(:target)
+          false -> any_impl_for
        end
      end

-      # Inline struct implementation for performance
-      @compile {:inline, struct_impl_for: 1}
+      # Check if compilation is available internally
+      Kernel.defp impl_for?(target) do
+        Code.ensure_compiled?(target) and
+          function_exported?(target, :__impl__, 1)
+      end

-      unless Module.defines_type?(__MODULE__, {:t, 0}) do
+      # Inline any and struct implementations
+      @compile {:inline, any_impl_for: 0, struct_impl_for: 1, impl_for?: 1}
+
+      unless Kernel.Typespec.defines_type?(__MODULE__, :t, 0) do
        @type t :: term
      end

@@ -624,31 +491,29 @@ defmodule Protocol do
      @doc false
      @spec __protocol__(:module) :: __MODULE__
      @spec __protocol__(:functions) :: unquote(Protocol.__functions_spec__(@functions))
-      @spec __protocol__(:consolidated?) :: false
-      @spec __protocol__(:impls) :: :not_consolidated
-      Kernel.def(__protocol__(:module), do: __MODULE__)
-      Kernel.def(__protocol__(:functions), do: unquote(:lists.sort(@functions)))
-      Kernel.def(__protocol__(:consolidated?), do: false)
-      Kernel.def(__protocol__(:impls), do: :not_consolidated)
+      @spec __protocol__(:consolidated?) :: boolean
+      Kernel.def __protocol__(:module), do: __MODULE__
+      Kernel.def __protocol__(:functions), do: unquote(:lists.sort(@functions))
+      Kernel.def __protocol__(:consolidated?), do: false
    end
  end

  @doc false
-  def __functions_spec__([]), do: []
-
-  def __functions_spec__([head | tail]),
-    do: [:lists.foldl(&{:|, [], [&1, &2]}, head, tail), quote(do: ...)]
+  def __functions_spec__([]),
+    do: []
+  def __functions_spec__([h|t]),
+    do: [:lists.foldl(&{:|, [], [&1, &2]}, h, t), quote(do: ...)]

  @doc false
  def __impl__(protocol, opts) do
    do_defimpl(protocol, :lists.keysort(1, opts))
  end

-  defp do_defimpl(protocol, do: block, for: for) when is_list(for) do
-    for f <- for, do: do_defimpl(protocol, do: block, for: f)
+  defp do_defimpl(protocol, [do: block, for: for]) when is_list(for) do
+    for f <- for, do: do_defimpl(protocol, [do: block, for: f])
  end

-  defp do_defimpl(protocol, do: block, for: for) do
+  defp do_defimpl(protocol, [do: block, for: for]) do
    # Unquote the implementation just later
    # when all variables will already be injected
    # into the module body.
@@ -658,28 +523,35 @@ defmodule Protocol do
        @spec __impl__(:for) :: unquote(for)
        @spec __impl__(:target) :: __MODULE__
        @spec __impl__(:protocol) :: unquote(protocol)
-        def __impl__(:for), do: unquote(for)
-        def __impl__(:target), do: __MODULE__
+        def __impl__(:for),      do: unquote(for)
+        def __impl__(:target),   do: __MODULE__
        def __impl__(:protocol), do: unquote(protocol)
      end

    quote do
      protocol = unquote(protocol)
-      for = unquote(for)
-      name = Module.concat(protocol, for)
+      for      = unquote(for)
+      name     = Module.concat(protocol, for)

-      Protocol.assert_protocol!(protocol)
-      Protocol.__ensure_defimpl__(protocol, for, __ENV__)
+      # TODO: Remove this by 1.3
+      if Atom.to_string(protocol) =~ "Elixir.Access" do
+        :elixir_errors.warn __ENV__.line, __ENV__.file,
+          "implementation of the Access protocol is deprecated. For customization of " <>
+          "the data[key] syntax, please implement the Access behaviour in your struct"
+      else
+        Protocol.assert_protocol!(protocol)
+        Protocol.__ensure_defimpl__(protocol, for, __ENV__)
+      end

      defmodule name do
        @behaviour protocol
-        @protocol protocol
-        @for for
+        @protocol  protocol
+        @for       for

        unquote(block)

-        Module.register_attribute(__MODULE__, :protocol_impl, persist: true)
-        @protocol_impl [protocol: @protocol, for: @for]
+        Module.register_attribute(__MODULE__, :impl, persist: true)
+        @impl [protocol: @protocol, for: @for]

        unquote(impl)
      end
@@ -690,55 +562,51 @@ defmodule Protocol do
  def __derive__(derives, for, %Macro.Env{} = env) when is_atom(for) do
    struct =
      if for == env.module do
-        Module.get_attribute(for, :struct) || raise "struct is not defined for #{inspect(for)}"
+        Module.get_attribute(for, :struct) ||
+          raise "struct is not defined for #{inspect for}"
      else
        for.__struct__
      end

-    foreach = fn
+    :lists.foreach(fn
      proto when is_atom(proto) ->
        derive(proto, for, struct, [], env)
-
      {proto, opts} when is_atom(proto) ->
        derive(proto, for, struct, opts, env)
-    end
-
-    :lists.foreach(foreach, :lists.flatten(derives))
+    end, :lists.flatten(derives))

    :ok
  end

  defp derive(protocol, for, struct, opts, env) do
-    extra = ", cannot derive #{inspect(protocol)} for #{inspect(for)}"
+    extra = ", cannot derive #{inspect protocol} for #{inspect for}"
    assert_protocol!(protocol, extra)
    __ensure_defimpl__(protocol, for, env)
    assert_impl!(protocol, Any, extra)

    # Clean up variables from eval context
-    env = :elixir_env.reset_vars(env)
+    env  = %{env | vars: [], export_vars: nil}
    args = [for, struct, opts]
    impl = Module.concat(protocol, Any)

-    :elixir_module.expand_callback(env.line, impl, :__deriving__, args, env, fn mod, fun, args ->
-      if function_exported?(mod, fun, length(args)) do
-        apply(mod, fun, args)
-      else
-        quoted =
-          quote do
-            Module.register_attribute(__MODULE__, :protocol_impl, persist: true)
-            @protocol_impl [protocol: unquote(protocol), for: unquote(for)]
+    :elixir_module.expand_callback(env.line, impl, :__deriving__, args, env, fn
+      mod, fun, args ->
+        if function_exported?(mod, fun, length(args)) do
+          apply(mod, fun, args)
+        else
+          Module.create(Module.concat(protocol, for), quote do
+            Module.register_attribute(__MODULE__, :impl, persist: true)
+            @impl [protocol: unquote(protocol), for: unquote(for)]

            @doc false
            @spec __impl__(:target) :: unquote(impl)
            @spec __impl__(:protocol) :: unquote(protocol)
            @spec __impl__(:for) :: unquote(for)
-            def __impl__(:target), do: unquote(impl)
+            def __impl__(:target),   do: unquote(impl)
            def __impl__(:protocol), do: unquote(protocol)
-            def __impl__(:for), do: unquote(for)
-          end
-
-        Module.create(Module.concat(protocol, for), quoted, Macro.Env.location(env))
-      end
+            def __impl__(:for),      do: unquote(for)
+          end, Macro.Env.location(env))
+        end
    end)
  end

@@ -746,33 +614,42 @@ defmodule Protocol do
  def __ensure_defimpl__(protocol, for, env) do
    if Protocol.consolidated?(protocol) do
      message =
-        "the #{inspect(protocol)} protocol has already been consolidated, an " <>
-          "implementation for #{inspect(for)} has no effect. If you want to " <>
-          "implement protocols after compilation or during tests, check the " <>
-          "\"Consolidation\" section in the documentation for Kernel.defprotocol/2"
-
+        "the #{inspect protocol} protocol has already been consolidated" <>
+        ", an implementation for #{inspect for} has no effect"
      :elixir_errors.warn(env.line, env.file, message)
    end
-
    :ok
  end

+  @doc false
+  def __spec__?(module, name, arity) do
+    signature = {name, arity}
+
+    specs = Module.get_attribute(module, :spec)
+    found =
+      :lists.map(fn {:spec, expr, caller} ->
+        if Kernel.Typespec.spec_to_signature(expr) == signature do
+          Kernel.Typespec.define_spec(:callback, expr, caller)
+          true
+        end
+      end, specs)
+
+    :lists.any(& &1 == true, found)
+  end
+
  ## Helpers

-  @doc false
-  def __builtin__ do
-    [
-      is_tuple: Tuple,
-      is_atom: Atom,
-      is_list: List,
-      is_map: Map,
-      is_bitstring: BitString,
-      is_integer: Integer,
-      is_float: Float,
-      is_function: Function,
-      is_pid: PID,
-      is_port: Port,
-      is_reference: Reference
-    ]
+  defp builtin do
+    [is_tuple: Tuple,
+     is_atom: Atom,
+     is_list: List,
+     is_map: Map,
+     is_bitstring: BitString,
+     is_integer: Integer,
+     is_float: Float,
+     is_function: Function,
+     is_pid: PID,
+     is_port: Port,
+     is_reference: Reference]
  end
 end
@@ -5,13 +5,13 @@ defmodule Range do
  A range represents a discrete number of values where
  the first and last values are integers.

-  Ranges can be either increasing (`first <= last`) or
-  decreasing (`first > last`). Ranges are also always
+  Ranges can be either increasing (first <= last) or
+  decreasing (first > last). Ranges are also always
  inclusive.

-  A range is represented internally as a struct. However,
+  A Range is represented internally as a struct. However,
  the most common form of creating and matching on ranges
-  is via the `../2` macro, auto-imported from `Kernel`:
+  is via the `../2` macro, auto-imported from Kernel:

      iex> range = 1..3
      1..3
@@ -21,26 +21,11 @@ defmodule Range do
      iex> last
      3

-  A range implements the `Enumerable` protocol, which means
-  functions in the `Enum` module can be used to work with
-  ranges:
-
-      iex> range = 1..10
-      1..10
-      iex> Enum.reduce(range, 0, fn i, acc -> i * i + acc end)
-      385
-      iex> Enum.count(range)
-      10
-      iex> Enum.member?(range, 11)
-      false
-      iex> Enum.member?(range, 8)
-      true
-
  """

  defstruct first: nil, last: nil

-  @type t :: %Range{first: integer, last: integer}
+  @type t :: %Range{}
  @type t(first, last) :: %Range{first: first, last: last}

  @doc """
@@ -53,44 +38,57 @@ defmodule Range do

  def new(first, last) do
    raise ArgumentError,
-          "ranges (first..last) expect both sides to be integers, " <>
-            "got: #{inspect(first)}..#{inspect(last)}"
+      "ranges (first..last) expect both sides to be integers, " <>
+      "got: #{inspect first}..#{inspect last}"
  end

-  # TODO: Remove by 2.0
-  @doc false
-  @deprecated "Pattern match on first..last instead"
+  @doc """
+  Returns `true` if the given `term` is a range.
+
+  It does not check if the range is valid.
+
+  ## Examples
+
+      iex> Range.range?(1..3)
+      true
+
+      iex> Range.range?(0)
+      false
+
+  """
+  @spec range?(%Range{}) :: true
+  @spec range?(term) :: false
  def range?(term)
-  def range?(first..last) when is_integer(first) and is_integer(last), do: true
+  def range?(%Range{}), do: true
  def range?(_), do: false
 end

 defimpl Enumerable, for: Range do
-  def reduce(first..last, acc, fun) do
-    reduce(first, last, acc, fun, _up? = last >= first)
+  def reduce(first .. last, acc, fun) do
+    reduce(first, last, acc, fun, last >= first)
  end

-  defp reduce(_first, _last, {:halt, acc}, _fun, _up?) do
+  defp reduce(_x, _y, {:halt, acc}, _fun, _up) do
    {:halted, acc}
  end

-  defp reduce(first, last, {:suspend, acc}, fun, up?) do
-    {:suspended, acc, &reduce(first, last, &1, fun, up?)}
+  defp reduce(x, y, {:suspend, acc}, fun, up) do
+    {:suspended, acc, &reduce(x, y, &1, fun, up)}
  end

-  defp reduce(first, last, {:cont, acc}, fun, _up? = true) when first <= last do
-    reduce(first + 1, last, fun.(first, acc), fun, _up? = true)
+  defp reduce(x, y, {:cont, acc}, fun, true) when x <= y do
+    reduce(x + 1, y, fun.(x, acc), fun, true)
  end

-  defp reduce(first, last, {:cont, acc}, fun, _up? = false) when first >= last do
-    reduce(first - 1, last, fun.(first, acc), fun, _up? = false)
+  defp reduce(x, y, {:cont, acc}, fun, false) when x >= y do
+    reduce(x - 1, y, fun.(x, acc), fun, false)
  end

  defp reduce(_, _, {:cont, acc}, _fun, _up) do
    {:done, acc}
  end

-  def member?(first..last, value) when is_integer(value) do
+  def member?(first .. last, value) when is_integer(value) do
    if first <= last do
      {:ok, first <= value and value <= last}
    else
@@ -98,37 +96,23 @@ defimpl Enumerable, for: Range do
    end
  end

-  def member?(_.._, _value) do
+  def member?(_ .. _, _value) do
    {:ok, false}
  end

-  def count(first..last) do
+  def count(first .. last) do
    if first <= last do
      {:ok, last - first + 1}
    else
      {:ok, first - last + 1}
    end
  end
-
-  def slice(first..last) do
-    if first <= last do
-      {:ok, last - first + 1, &slice_asc(first + &1, &2)}
-    else
-      {:ok, first - last + 1, &slice_desc(first - &1, &2)}
-    end
-  end
-
-  defp slice_asc(current, 1), do: [current]
-  defp slice_asc(current, remaining), do: [current | slice_asc(current + 1, remaining - 1)]
-
-  defp slice_desc(current, 1), do: [current]
-  defp slice_desc(current, remaining), do: [current | slice_desc(current - 1, remaining - 1)]
 end

 defimpl Inspect, for: Range do
  import Inspect.Algebra

-  def inspect(first..last, opts) do
-    concat([to_doc(first, opts), "..", to_doc(last, opts)])
+  def inspect(first .. last, opts) do
+    concat [to_doc(first, opts), "..", to_doc(last, opts)]
  end
 end
@@ -1,10 +1,10 @@
 defmodule Record do
  @moduledoc """
-  Module to work with, define, and import records.
+  Module to work with, define and import records.

  Records are simply tuples where the first element is an atom:

-      iex> Record.is_record({User, "john", 27})
+      iex> Record.is_record {User, "john", 27}
      true

  This module provides conveniences for working with records at
@@ -17,14 +17,15 @@ defmodule Record do
    1. to work with short, internal data
    2. to interface with Erlang records

-  The macros `defrecord/3` and `defrecordp/3` can be used to create records
-  while `extract/2` and `extract_all/1` can be used to extract records from
-  Erlang files.
+  The macros `defrecord/3` and `defrecordp/3` can be used to create
+  records while `extract/2` can be used to extract records from Erlang
+  files.

  ## Types

-  Types can be defined for tuples with the `record/2` macro (only available in
-  typespecs). This macro will expand to a tuple as seen in the example below:
+  Types can be defined for tuples with the `record/2` macro (only available
+  in typespecs). Like with the generated record macros it will expand to
+  a tuple.

      defmodule MyModule do
        require Record
@@ -33,43 +34,14 @@ defmodule Record do
        @type user :: record(:user, name: String.t, age: integer)
        # expands to: "@type user :: {:user, String.t, integer}"
      end
-
  """

  @doc """
  Extracts record information from an Erlang file.

  Returns a quoted expression containing the fields as a list
-  of tuples.
-
-  `name`, which is the name of the extracted record, is expected to be an atom
-  *at compile time*.
-
-  ## Options
-
-  This function accepts the following options, which are exclusive to each other
-  (i.e., only one of them can be used in the same call):
-
-    * `:from` - (binary representing a path to a file) path to the Erlang file
-      that contains the record definition to extract; with this option, this
-      function uses the same path lookup used by the `-include` attribute used in
-      Erlang modules.
-
-    * `:from_lib` - (binary representing a path to a file) path to the Erlang
-      file that contains the record definition to extract; with this option,
-      this function uses the same path lookup used by the `-include_lib`
-      attribute used in Erlang modules.
-
-    * `:includes` - (a list of directories as binaries) if the record being
-      extracted depends on relative includes, this option allows developers
-      to specify the directory those relative includes exist
-
-    * `:macros` - (keyword list of macro names and values) if the record
-      being extract depends on the values of macros, this option allows
-      the value of those macros to be set
-
-  These options are expected to be literals (including the binary values) at
-  compile time.
+  of tuples. It expects the record name to be an atom and the
+  library path to be a string at expansion time.

  ## Examples

@@ -80,7 +52,6 @@ defmodule Record do
       uid: :undefined, gid: :undefined]

  """
-  @spec extract(name :: atom, keyword) :: keyword
  def extract(name, opts) when is_atom(name) and is_list(opts) do
    Record.Extractor.extract(name, opts)
  end
@@ -88,34 +59,18 @@ defmodule Record do
  @doc """
  Extracts all records information from an Erlang file.

-  Returns a keyword list of `{record_name, fields}` tuples where `record_name`
-  is the name of an extracted record and `fields` is a list of `{field, value}`
-  tuples representing the fields for that record.
+  Returns a keyword list containing extracted record names as keys, and
+  lists of tuples describing the fields as values. It expects a named
+  argument :from or :from_lib, which correspond to *include* or
+  *include_lib* attribute from Erlang modules, respectively.

-  ## Options
-
-  This function accepts the following options, which are exclusive to each other
-  (i.e., only one of them can be used in the same call):
-
-    * `:from` - (binary representing a path to a file) path to the Erlang file
-      that contains the record definitions to extract; with this option, this
-      function uses the same path lookup used by the `-include` attribute used in
-      Erlang modules.
-    * `:from_lib` - (binary representing a path to a file) path to the Erlang
-      file that contains the record definitions to extract; with this option,
-      this function uses the same path lookup used by the `-include_lib`
-      attribute used in Erlang modules.
-
-  These options are expected to be literals (including the binary values) at
-  compile time.
  """
-  @spec extract_all(keyword) :: [{name :: atom, keyword}]
  def extract_all(opts) when is_list(opts) do
    Record.Extractor.extract_all(opts)
  end

  @doc """
-  Checks if the given `data` is a record of kind `kind`.
+  Checks if the given `data` is a record of `kind`.

  This is implemented as a macro so it can be used in guard clauses.

@@ -126,9 +81,21 @@ defmodule Record do
      true

  """
-  defguard is_record(data, kind)
-           when is_atom(kind) and is_tuple(data) and tuple_size(data) > 0 and
-                  elem(data, 0) == kind
+  defmacro is_record(data, kind) do
+    case Macro.Env.in_guard?(__CALLER__) do
+      true ->
+        quote do
+          is_tuple(unquote(data)) and tuple_size(unquote(data)) > 0
+            and :erlang.element(1, unquote(data)) == unquote(kind)
+        end
+      false ->
+        quote do
+          result = unquote(data)
+          is_tuple(result) and tuple_size(result) > 0
+            and :erlang.element(1, result) == unquote(kind)
+        end
+    end
+  end

  @doc """
  Checks if the given `data` is a record.
@@ -145,31 +112,28 @@ defmodule Record do
      false

  """
-  defguard is_record(data)
-           when is_tuple(data) and tuple_size(data) > 0 and is_atom(elem(data, 0))
+  defmacro is_record(data) do
+    case Macro.Env.in_guard?(__CALLER__) do
+      true ->
+        quote do
+          is_tuple(unquote(data)) and tuple_size(unquote(data)) > 0
+            and is_atom(:erlang.element(1, unquote(data)))
+        end
+      false ->
+        quote do
+          result = unquote(data)
+          is_tuple(result) and tuple_size(result) > 0
+            and is_atom(:erlang.element(1, result))
+        end
+    end
+  end

  @doc """
-  Defines a set of macros to create, access, and pattern match
-  on a record.
+  Defines a set of macros to create and access a record.

-  The name of the generated macros will be `name` (which has to be an
-  atom). `tag` is also an atom and is used as the "tag" for the record (i.e.,
-  the first element of the record tuple); by default (if `nil`), it's the same
-  as `name`. `kv` is a keyword list of `name: default_value` fields for the
-  new record.
-
-  The following macros are generated:
-
-    * `name/0` to create a new record with default values for all fields
-    * `name/1` to create a new record with the given fields and values,
-      to get the zero-based index of the given field in a record or to
-      convert the given record to a keyword list
-    * `name/2` to update an existing record with the given fields and values
-      or to access a given field in a given record
-
-  All these macros are public macros (as defined by `defmacro`).
-
-  See the "Examples" section for examples on how to use these macros.
+  The macros are going to have `name`, a tag (which defaults)
+  to the name if none is given, and a set of fields given by
+  `kv`.

  ## Examples

@@ -179,10 +143,7 @@ defmodule Record do
      end

  In the example above, a set of macros named `user` but with different
-  arities will be defined to manipulate the underlying record.
-
-      # Import the module to make the user macros locally available
-      import User
+  arities will be defined to manipulate the underlying record:

      # To create records
      record = user()        #=> {:user, "meg", 25}
@@ -194,10 +155,6 @@ defmodule Record do
      # To update the record
      user(record, age: 26) #=> {:user, "meg", 26}

-      # To get the zero-based index of the field in record tuple
-      # (index 0 is occupied by the record "tag")
-      user(:name) #=> 1
-
      # Convert a record to a keyword list
      user(record) #=> [name: "meg", age: 26]

@@ -209,28 +166,27 @@ defmodule Record do
      user(name: name) = record
      name #=> "meg"

-  By default, Elixir uses the record name as the first element of the tuple (the "tag").
-  However, a different tag can be specified when defining a record,
-  as in the following example, in which we use `Customer` as the second argument of `defrecord/3`:
+  By default, Elixir uses the record name as the first element of
+  the tuple (the tag). But it can be changed to something else:

      defmodule User do
        require Record
-        Record.defrecord :user, Customer, name: nil
+        Record.defrecord :user, User, name: nil
      end

      require User
-      User.user() #=> {Customer, nil}
+      User.user() #=> {User, nil}

-  ## Defining extracted records with anonymous functions in the values
+  ## Defining extracted records with anonymous functions

-  If a record defines an anonymous function in the default values, an
-  `ArgumentError` will be raised. This can happen unintentionally when defining
-  a record after extracting it from an Erlang library that uses anonymous
-  functions for defaults.
+  If a record defines an anonymous function, an ArgumentError
+  will occur if you attempt to create a record with it.
+  This can occur unintentionally when defining a record after extracting
+  it from an Erlang library that uses anonymous functions for defaults.

      Record.defrecord :my_rec, Record.extract(...)
      #=> ** (ArgumentError) invalid value for record field fun_field,
-      #=>   cannot escape #Function<12.90072148/2 in :erl_eval.expr/5>.
+      cannot escape #Function<12.90072148/2 in :erl_eval.expr/5>.

  To work around this error, redefine the field with your own &M.f/a function,
  like so:
@@ -240,18 +196,17 @@ defmodule Record do
        Record.defrecord :my_rec, Record.extract(...) |> Keyword.merge(fun_field: &__MODULE__.foo/2)
        def foo(bar, baz), do: IO.inspect({bar, baz})
      end
-
  """
  defmacro defrecord(name, tag \\ nil, kv) do
    quote bind_quoted: [name: name, tag: tag, kv: kv] do
      tag = tag || name
      fields = Record.__fields__(:defrecord, kv)

-      defmacro unquote(name)(args \\ []) do
+      defmacro(unquote(name)(args \\ [])) do
        Record.__access__(unquote(tag), unquote(fields), args, __CALLER__)
      end

-      defmacro unquote(name)(record, args) do
+      defmacro(unquote(name)(record, args)) do
        Record.__access__(unquote(tag), unquote(fields), record, args, __CALLER__)
      end
    end
@@ -265,11 +220,11 @@ defmodule Record do
      tag = tag || name
      fields = Record.__fields__(:defrecordp, kv)

-      defmacrop unquote(name)(args \\ []) do
+      defmacrop(unquote(name)(args \\ [])) do
        Record.__access__(unquote(tag), unquote(fields), args, __CALLER__)
      end

-      defmacrop unquote(name)(record, args) do
+      defmacrop(unquote(name)(record, args)) do
        Record.__access__(unquote(tag), unquote(fields), record, args, __CALLER__)
      end
    end
@@ -278,93 +233,81 @@ defmodule Record do
  # Normalizes of record fields to have default values.
  @doc false
  def __fields__(type, fields) do
-    normalizer_fun = fn
-      {key, value} when is_atom(key) ->
+    :lists.map(fn
+      {key, val} when is_atom(key) ->
        try do
-          Macro.escape(value)
+          Macro.escape(val)
        rescue
          e in [ArgumentError] ->
            raise ArgumentError, "invalid value for record field #{key}, " <> Exception.message(e)
        else
-          value -> {key, value}
+          val -> {key, val}
        end
-
      key when is_atom(key) ->
        {key, nil}
-
      other ->
-        raise ArgumentError, "#{type} fields must be atoms, got: #{inspect(other)}"
-    end
-
-    :lists.map(normalizer_fun, fields)
+        raise ArgumentError, "#{type} fields must be atoms, got: #{inspect other}"
+    end, fields)
  end

  # Callback invoked from record/0 and record/1 macros.
  @doc false
-  def __access__(tag, fields, args, caller) do
+  def __access__(atom, fields, args, caller) do
    cond do
      is_atom(args) ->
-        index(tag, fields, args)
-
+        index(atom, fields, args)
      Keyword.keyword?(args) ->
-        create(tag, fields, args, caller)
-
+        create(atom, fields, args, caller)
      true ->
-        fields = Macro.escape(fields)
-
        case Macro.expand(args, caller) do
-          {:{}, _, [^tag | list]} when length(list) == length(fields) ->
-            record = List.to_tuple([tag | list])
-            Record.__keyword__(tag, fields, record)
-
-          {^tag, arg} when length(fields) == 1 ->
-            Record.__keyword__(tag, fields, {tag, arg})
-
+          {:{}, _, [^atom|list]} when length(list) == length(fields) ->
+            record = List.to_tuple([atom|list])
+            Macro.escape(Record.__keyword__(atom, fields, record))
+          {^atom, arg} when length(fields) == 1 ->
+            Macro.escape(Record.__keyword__(atom, fields, {atom, arg}))
          _ ->
-            quote(do: Record.__keyword__(unquote(tag), unquote(fields), unquote(args)))
+            quote do: Record.__keyword__(unquote(atom), unquote(fields), unquote(args))
        end
    end
  end

  # Callback invoked from the record/2 macro.
  @doc false
-  def __access__(tag, fields, record, args, caller) do
+  def __access__(atom, fields, record, args, caller) do
    cond do
      is_atom(args) ->
-        get(tag, fields, record, args)
-
+        get(atom, fields, record, args)
      Keyword.keyword?(args) ->
-        update(tag, fields, record, args, caller)
-
+        update(atom, fields, record, args, caller)
      true ->
-        raise ArgumentError,
-              "expected arguments to be a compile time atom or a keyword list, got: " <>
-                Macro.to_string(args)
+        msg = "expected arguments to be a compile time atom or keywords, got: #{Macro.to_string args}"
+        raise ArgumentError, msg
    end
  end

  # Gets the index of field.
-  defp index(tag, fields, field) do
+  defp index(atom, fields, field) do
    if index = find_index(fields, field, 0) do
-      # Convert to Elixir index
-      index - 1
+      index - 1 # Convert to Elixir index
    else
-      raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(field)}"
+      raise ArgumentError, "record #{inspect atom} does not have the key: #{inspect field}"
    end
  end

  # Creates a new record with the given default fields and keyword values.
-  defp create(tag, fields, keyword, caller) do
+  defp create(atom, fields, keyword, caller) do
    in_match = Macro.Env.in_match?(caller)
-    keyword = apply_underscore(fields, keyword)

    {match, remaining} =
-      Enum.map_reduce(fields, keyword, fn {field, default}, each_keyword ->
+      Enum.map_reduce(fields, keyword, fn({field, default}, each_keyword) ->
        new_fields =
-          case Keyword.fetch(each_keyword, field) do
-            {:ok, value} -> value
-            :error when in_match -> {:_, [], nil}
-            :error -> Macro.escape(default)
+          case Keyword.has_key?(each_keyword, field) do
+            true  -> Keyword.get(each_keyword, field)
+            false ->
+              case in_match do
+                true  -> {:_, [], nil}
+                false -> Macro.escape(default)
+              end
          end

        {new_fields, Keyword.delete(each_keyword, field)}
@@ -372,91 +315,61 @@ defmodule Record do

    case remaining do
      [] ->
-        {:{}, [], [tag | match]}
-
-      _ ->
+        {:{}, [], [atom|match]}
+      _  ->
        keys = for {key, _} <- remaining, do: key
-        raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(hd(keys))}"
+        raise ArgumentError, "record #{inspect atom} does not have the key: #{inspect hd(keys)}"
    end
  end

  # Updates a record given by var with the given keyword.
-  defp update(tag, fields, var, keyword, caller) do
+  defp update(atom, fields, var, keyword, caller) do
    if Macro.Env.in_match?(caller) do
      raise ArgumentError, "cannot invoke update style macro inside match"
    end

-    keyword = apply_underscore(fields, keyword)
-
-    Enum.reduce(keyword, var, fn {key, value}, acc ->
+    Enum.reduce keyword, var, fn({key, value}, acc) ->
      index = find_index(fields, key, 0)
-
      if index do
        quote do
          :erlang.setelement(unquote(index), unquote(acc), unquote(value))
        end
      else
-        raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(key)}"
+        raise ArgumentError, "record #{inspect atom} does not have the key: #{inspect key}"
      end
-    end)
+    end
  end

  # Gets a record key from the given var.
-  defp get(tag, fields, var, key) do
+  defp get(atom, fields, var, key) do
    index = find_index(fields, key, 0)
-
    if index do
      quote do
        :erlang.element(unquote(index), unquote(var))
      end
    else
-      raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(key)}"
+      raise ArgumentError, "record #{inspect atom} does not have the key: #{inspect key}"
    end
  end

-  defp find_index([{k, _} | _], k, i), do: i + 2
-  defp find_index([{_, _} | t], k, i), do: find_index(t, k, i + 1)
+  defp find_index([{k, _}|_], k, i), do: i + 2
+  defp find_index([{_, _}|t], k, i), do: find_index(t, k, i + 1)
  defp find_index([], _k, _i), do: nil

  # Returns a keyword list of the record
  @doc false
-  def __keyword__(tag, fields, record) do
-    if is_record(record, tag) do
-      [_tag | values] = Tuple.to_list(record)
-
-      case join_keyword(fields, values, []) do
-        kv when is_list(kv) ->
-          kv
-
-        expected_fields ->
-          raise ArgumentError,
-                "expected argument to be a #{inspect(tag)} record with " <>
-                  "#{expected_fields} fields, got: " <> inspect(record)
-      end
+  def __keyword__(atom, fields, record) do
+    if is_record(record, atom) do
+      [_tag|values] = Tuple.to_list(record)
+      join_keyword(fields, values, [])
    else
-      raise ArgumentError,
-            "expected argument to be a literal atom, literal keyword or " <>
-              "a #{inspect(tag)} record, got runtime: " <> inspect(record)
+      msg = "expected argument to be a literal atom, literal keyword or a #{inspect atom} record, got runtime: #{inspect record}"
+      raise ArgumentError, msg
    end
  end

-  # Returns a keyword list, or expected number of fields on size mismatch
-  defp join_keyword([{field, _default} | fields], [value | values], acc),
-    do: join_keyword(fields, values, [{field, value} | acc])
-
-  defp join_keyword([], [], acc), do: :lists.reverse(acc)
-  defp join_keyword(rest_fields, _rest_values, acc), do: length(acc) + length(rest_fields)
-
-  defp apply_underscore(fields, keyword) do
-    case Keyword.fetch(keyword, :_) do
-      {:ok, default} ->
-        fields
-        |> Enum.map(fn {k, _} -> {k, default} end)
-        |> Keyword.merge(keyword)
-        |> Keyword.delete(:_)
-
-      :error ->
-        keyword
-    end
-  end
+  defp join_keyword([{field, _default}|fields], [value|values], acc),
+    do: join_keyword(fields, values, [{field, value}| acc])
+  defp join_keyword([], [], acc),
+    do: :lists.reverse(acc)
 end
@@ -1,31 +1,33 @@
 defmodule Record.Extractor do
  @moduledoc false

-  def extract(name, opts) do
-    extract_record(name, from_or_from_lib_file(opts))
+  # Retrieve a record definition from an Erlang file using
+  # the same lookup as the *include* attribute from Erlang modules.
+  def extract(name, from: file) when is_binary(file) do
+    extract_record(name, from_file(file))
  end

-  def extract_all(opts) do
-    extract_all_records(from_or_from_lib_file(opts))
+  # Retrieve a record definition from an Erlang file using
+  # the same lookup as the *include_lib* attribute from Erlang modules.
+  def extract(name, from_lib: file) when is_binary(file) do
+    extract_record(name, from_lib_file(file))
  end

-  defp from_or_from_lib_file(opts) do
-    cond do
-      file = opts[:from] ->
-        {from_file(file), Keyword.delete(opts, :from)}
+  # Retrieve all records definitions from an Erlang file using
+  # the same lookup as the *include* attribute from Erlang modules.
+  def extract_all(from: file) when is_binary(file) do
+    extract_all_records(from_file(file))
+  end

-      file = opts[:from_lib] ->
-        {from_lib_file(file), Keyword.delete(opts, :from_lib)}
-
-      true ->
-        raise ArgumentError, "expected :from or :from_lib to be given as option"
-    end
+  # Retrieve all records definitions from an Erlang file using
+  # the same lookup as the *include_lib* attribute from Erlang modules.
+  def extract_all(from_lib: file) when is_binary(file) do
+    extract_all_records(from_lib_file(file))
  end

  # Find file using the same lookup as the *include* attribute from Erlang modules.
  defp from_file(file) do
-    file = String.to_charlist(file)
-
+    file = String.to_char_list(file)
    case :code.where_is_file(file) do
      :non_existing -> file
      realfile -> realfile
@@ -34,34 +36,29 @@ defmodule Record.Extractor do

  # Find file using the same lookup as the *include_lib* attribute from Erlang modules.
  defp from_lib_file(file) do
-    [app | path] = :filename.split(String.to_charlist(file))
-
+    [app|path] = :filename.split(String.to_char_list(file))
    case :code.lib_dir(List.to_atom(app)) do
      {:error, _} ->
        raise ArgumentError, "lib file #{file} could not be found"
-
      libpath ->
-        :filename.join([libpath | path])
+        :filename.join([libpath|path])
    end
  end

  # Retrieve the record with the given name from the given file
-  defp extract_record(name, {file, opts}) do
-    form = read_file(file, opts)
+  defp extract_record(name, file) do
+    form = read_file(file)
    records = extract_records(form)
-
    if record = List.keyfind(records, name, 0) do
      parse_record(record, form)
    else
-      raise ArgumentError,
-            "no record #{name} found at #{file}. Or the record does not exist or " <>
-              "its entry is malformed or depends on other include files"
+      raise ArgumentError, "no record #{name} found at #{file}"
    end
  end

  # Retrieve all records from the given file
-  defp extract_all_records({file, opts}) do
-    form = read_file(file, opts)
+  defp extract_all_records(file) do
+    form = read_file(file)
    records = extract_records(form)
    for rec = {name, _fields} <- records, do: {name, parse_record(rec, form)}
  end
@@ -75,11 +72,10 @@ defmodule Record.Extractor do
  # includes record but with macros and other attributes expanded,
  # such as "-include(...)" and "-include_lib(...)". This is done
  # by using Erlang's epp.
-  defp read_file(file, opts) do
-    case :epp.parse_file(file, opts) do
+  defp read_file(file) do
+    case :epp.parse_file(file, []) do
      {:ok, form} ->
        form
-
      other ->
        raise "error parsing file #{file}, got: #{inspect(other)}"
    end
@@ -89,7 +85,9 @@ defmodule Record.Extractor do
  # list of tuples where the first element is the field
  # and the second is its default value.
  defp parse_record({_name, fields}, form) do
-    cons = List.foldr(fields, {nil, 0}, fn f, acc -> {:cons, 0, parse_field(f), acc} end)
+    cons = List.foldr fields, {nil, 0}, fn f, acc ->
+      {:cons, 0, parse_field(f), acc}
+    end
    eval_record(cons, form)
  end

@@ -106,10 +104,12 @@ defmodule Record.Extractor do
  end

  defp eval_record(cons, form) do
-    form = form ++ [{:function, 0, :hello, 0, [{:clause, 0, [], [], [cons]}]}]
+    form = form ++
+      [{:function, 0, :hello, 0, [
+         {:clause, 0, [], [], [cons]}]}]

-    {:function, 0, :hello, 0, [{:clause, 0, [], [], [record_ast]}]} =
-      :erl_expand_records.module(form, []) |> List.last()
+    {:function, 0, :hello, 0, [
+      {:clause, 0, [], [], [record_ast]}]} = :erl_expand_records.module(form, []) |> List.last

    {:value, record, _} = :erl_eval.expr(record_ast, [])
    record
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
José Valim	9c91d2cc91	Update CHANGELOG.md	2016-10-29 10:40:53 +02:00
José Valim	3dbfb92860	Release v1.2.6	2016-06-06 15:26:56 +02:00
José Valim	a77b85665a	Mark variables captured by modules as generated Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-06-06 15:18:56 +02:00
José Valim	f27a6735d6	Update CHANGELOG	2016-06-03 01:51:52 +02:00
José Valim	e415148d3a	More explicitly use the term annotation throughout	2016-06-03 01:19:35 +02:00
José Valim	9d95a0bcbf	Propagate generated: true in Elixir definitions	2016-06-03 00:31:31 +02:00
José Valim	3df2a02d23	Bump to 1.2.6-dev	2016-06-03 00:27:36 +02:00
José Valim	55a4c5980d	Support generated: true in quote Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-06-02 23:54:30 +02:00
Eric Meadows-Jönsson	30cbdb8fbf	Fix binary typespecs * Removes <<_::sizeunit>> Adds <<_::size, _::_*unit>> Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-05-30 14:06:46 +02:00
Daniel Perez	d1773cf96d	Fix bug in Path.join. Fix #4252 . Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-05-21 17:32:33 +02:00
José Valim	5754da26f2	Fixes for Erlang 19 RC Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-05-16 13:06:27 +02:00
Miles Starkenburg	41b5091073	Fix nfd normalization bug (#4606 ) * Fix nfd normalization bug * Change String.normalize return type to binary Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-05-13 09:29:45 +02:00
José Valim	e5374cf5d3	Release v1.2.5	2016-04-30 13:34:56 +02:00
José Valim	352a357460	Do not assume @impl is a list, closes #4519 Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-30 13:29:32 +02:00
Michael Pope	cc018f90bf	Stringify truncated function data in Logger (#4562 ) Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-30 13:27:46 +02:00
José Valim	9374fbeae6	Revert manifest changes for release (they are part of master)	2016-04-30 13:27:30 +02:00
José Valim	9a44775b68	Make prune part of the public API in the formatter Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-30 13:25:05 +02:00
José Valim	07c6356354	Ensure poorly formatted chardata is pruned in Logger watcher Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-30 13:24:40 +02:00
Aleksei Magusev	55b124a478	Fix String.replace_trailing/3 replacement bug	2016-04-25 18:33:32 +02:00
Aleksei Magusev	5249d1d2f0	Fix String.replace_leading/3 replacement bug	2016-04-25 18:33:22 +02:00
Aleksei Magusev	59c0752143	Fix String.replace_leading/3 bug when the rest of string equals match	2016-04-25 18:33:08 +02:00
José Valim	39160df6a6	Improve Access deprecation warning	2016-04-15 09:36:46 +02:00
José Valim	08d2aaaf53	Also purge modules on outdated manifest Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-13 17:17:39 +02:00
José Valim	715a38a6e5	Integrate non-fetchable (path) dependencies into compilers This commit changes Elixir compilers so a path dependencies no longer forces the "parent" project to recompile. This means each compiler must know how to track dependencies but it gives faster compilation times as a benefit. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-13 16:29:57 +02:00
José Valim	7cc1ab4c63	Migrate from previous manifest versions Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-13 13:27:40 +02:00
José Valim	3798dff0fc	Only recompile empty files if they changed Prior to this commit, an Elixir file that did not generate any modules would always be regenerated whenever mix compile was invoked. This commit addresses this issue by keeping source files on its own rows in the Elixir manifest. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-04-13 12:56:00 +02:00
José Valim	17e8dbbf16	Release v1.2.4	2016-04-01 12:08:10 +02:00
José Valim	be7e6565f1	Merge pull request #4453 from sasa1977/purge-erlang-modules-on-recompilation purge erlang modules on recompilation Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-30 18:57:43 +02:00
José Valim	c0770bace0	Include archive.check inside deps.check	2016-03-30 16:04:55 +02:00
José Valim	788a3cf242	Merge branch 'jv-nerves' into v1.2	2016-03-30 15:09:30 +02:00
José Valim	598c33d246	Fold decomposition recursions at compile time	2016-03-29 16:55:22 +02:00
José Valim	2bfd924ca8	Do not reorder starting classes	2016-03-29 13:37:34 +02:00
José Valim	28f553aa63	Handle compositios with non-zero combining class	2016-03-29 13:20:51 +02:00
José Valim	ae2da553e8	More optimizations and improvements to normalization	2016-03-29 12:55:40 +02:00
José Valim	e96fd72841	Make decomposition recursive and consider exclusion list	2016-03-29 11:49:49 +02:00
José Valim	9d9417ec1b	Use combining_classes from UnicodeData	2016-03-29 11:11:29 +02:00
José Valim	3006ace8f5	Rely only on UnicodeData for composition/decomposition Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-29 00:56:06 +02:00
José Valim	b558b90253	Merge pull request #4409 from whatyouhide/version-build-metadata-fix Allow dots in the metadata info in Version.parse/1 Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:40:48 +01:00
Aleksei Magusev	a97fcf932c	Add a note about line filter for a file with multiple test cases Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:40:34 +01:00
Wojtek Mach	f438efbfca	Remove reference to old `Inspect.Opts.new` Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:40:27 +01:00
José Valim	d0dd0bd0e4	Clean up unicode range parsing Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:35:03 +01:00
José Valim	77b5fe0e9f	Update Unicode to 8.0.0 (equivalent pending) Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:34:55 +01:00
José Valim	dbc6127820	Avoid regular expressions Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:34:48 +01:00
Abel Muiño	2eb77e12f0	New definition of whitespace & breakable whitespace All whitespace can be removed by `strip` but only breakable whitespace can be used as a delimiter by `split`, with updated docs for String.split/1 Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-22 19:34:38 +01:00
José Valim	ffb626602c	Add tests for archive check	2016-03-19 19:02:41 +01:00
José Valim	f571fb74c4	Ensure mix deps.compile --include-children recurs on root dep	2016-03-19 17:42:12 +01:00
José Valim	7c07476db7	Add :archives option to Mix.Project	2016-03-19 15:26:40 +01:00
José Valim	e3be6dd0e9	Add deps.precompile hook and --include-children option	2016-03-19 14:24:17 +01:00
José Valim	c076fdb030	Ensure Application.spec/2 returns nil for unknown applications Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-19 14:03:50 +01:00
Andrea Leopardi	173c57fed2	Fix a possible binary leak in Integer.parse/1 Integer.parse/1 followed this pattern: defp do_parse(<<char, rest :: binary>>, ...) do ... # instead of re-using the original binary, we do this {..., <<char, rest :: binary>>} end This causes a new binary to be created instead of `rest` just being a sub-binary. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-03-02 19:52:48 +01:00
José Valim	737ac62926	Release v1.2.3	2016-02-21 22:28:30 +01:00
José Valim	9dcc0e140b	Support canonical URLs Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 21:42:01 +01:00
José Valim	e4e5481ca1	Update CHANGELOG	2016-02-21 17:57:10 +01:00
José Valim	c3df6806b3	Simplify padding rules Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 17:56:14 +01:00
Paulo Almeida	6dc523074d	Add option to omit / ignore padding Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 17:56:08 +01:00
Daniel Perez	5746cbf1e3	Add doc about ignore: :whitespace to Base.decode64. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 17:56:05 +01:00
Artur Cygan	51966e92a7	Update base.ex Clean up doc Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 17:56:01 +01:00
Daniel Perez	498057c51b	Add option to ignore whitespace to base64 decoding. Close #4186 . Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-21 17:55:02 +01:00
José Valim	b3c26a8633	Improve helpers docs	2016-02-17 19:18:10 +01:00
José Valim	5e218e77bf	Update CHANGELOG	2016-02-17 00:39:19 +01:00
José Valim	56fbf2a399	Add Mix.Project.deps_paths Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-17 00:34:59 +01:00
José Valim	c3582f9617	Reject non fullfilled optional dependencies later on Imagine this dependency tree: * parent * child * ecto * postgrex * ja_serializer * ecto where postgrex is an optional dependency of Ecto. Because optional dependencies were rejected later on, ecto would have its postgrex dependency stripped and later failed to top-sort. This commit changes it to so optional dependencies are rejected only later on. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-17 00:34:52 +01:00
José Valim	bd83a45215	Fix typespecs table Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-02-16 19:44:05 +01:00
José Valim	52dc944cfb	Do not allow negative line numbers without generated annotation	2016-02-15 11:47:46 +01:00
José Valim	3d27c749e1	Remove outdated debug_info test	2016-02-01 09:45:23 +01:00
José Valim	75d679cdc8	Merge pull request #4247 from stephenmoloney/rstrip-bug String.replace_trailing bug fix.	2016-02-01 09:22:05 +01:00
José Valim	2c9f28ecc3	Remove debug_info from unicode	2016-02-01 09:21:38 +01:00
José Valim	9decf4c78a	Release v1.2.2	2016-01-31 10:17:08 +01:00
José Valim	e2463a5589	Limit the list of attributes we consider reserved	2016-01-31 09:30:51 +01:00
José Valim	a825f5a0c8	Force recompilation if dependency was recently fetched	2016-01-29 13:20:47 +01:00
José Valim	3c0d26cb74	Raise if trying to override reserved tag, closes #4236	2016-01-29 00:32:00 +01:00
José Valim	f7a31ac804	Update CHANGELOG	2016-01-27 13:05:25 +01:00
José Valim	31aebcdc59	Automatically merge manager according to internal priority, closes #4230	2016-01-27 12:56:16 +01:00
José Valim	afbac81918	Do not require all compilers available on manifest Closes #4228 Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-27 10:11:38 +01:00
José Valim	0b78f86f08	Do not rely on compiled functions in Mix for autoload Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-25 10:00:55 +01:00
José Valim	7180b98f47	Support disabling autoload after compilation Useful for delaying loading of modules that may depend on NIFs until necessary. Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-25 00:13:37 +01:00
José Valim	021cca436d	Do not include debug_info in metadata String modules Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-25 00:13:28 +01:00
José Valim	a3d88dc406	Release v1.2.1	2016-01-14 19:25:11 +01:00
Daniel Azuma	58a6291f17	Fix a crash in Macro.to_string if a tree looks like a sigil but the function is not an atom Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-13 11:19:58 +01:00
Aleksei Magusev	81884247d7	Warn when defimp is called for consolidated protocol Conflicts: lib/elixir/lib/protocol.ex	2016-01-12 10:50:29 +01:00
Adrien Moreau	c07a34f9a8	Correct the type definition of ExUnit.state for the failed state Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-12 09:20:45 +01:00
José Valim	e05bfc78cb	Improve docs and error handling for Access Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-10 22:52:08 +01:00
Aleksei Magusev	cb430702c9	Preserve variable metadata during collection from assertion pattern Closes #4174.	2016-01-09 20:47:46 +01:00
Aleksei Magusev	6aaa4bb06d	Do not warn in match assertion if variable is reused in pattern Having the folowing assertion `assert {var, var} = {1, 1}`, the code produced previously: [var] = case(right) do {var, var} -> #... [var] _ -> #... end And with the patch: [var, var] = case(right) do {var, var} -> #... [var, var] _ -> #... end	2016-01-06 23:56:44 +01:00
Thomas Fisher	a6b80a19c5	Fixes bug in IEx.Config.configuration IEx.Config.configuration was raising a FunctionClauseError since it did not have a default value for width Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-06 18:58:42 +01:00
Aleksei Magusev	8be0ad0499	Correct Macro.to_string/1 formatting for capture operator Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-06 18:58:07 +01:00
José Valim	8da4936ac3	Ensure dependencies are properly skipped when running in another environment Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-06 18:57:54 +01:00
James Fish	bcc92ccc40	Support remote pids/ports with IEx helper i/1 Signed-off-by: José Valim <jose.valim@plataformatec.com.br>	2016-01-02 18:54:07 +01:00
José Valim	d64d4b009c	v1.2 branch	2016-01-01 11:51:36 +01:00
@@ -1 +1 @@
 .7.4
 .2.6