Release v1.5.3

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

.appveyor.yml

@@ -7,12 +7,3 @@ 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

.formatter.exs

@@ -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
-  ]
-]

.gitignore

@@ -3,6 +3,7 @@
 /lib/*/_build/
 /lib/*/tmp/
 /lib/elixir/src/*_parser.erl
+/lib/elixir/src/elixir.app.src
 /lib/elixir/test/ebin/
 /man/elixir.1
 /man/iex.1

.travis.yml

@@ -1,31 +1,30 @@
-language: bash
+language: erlang
 sudo: false
 
-env:
-  global:
-    - ELIXIR_ASSERT_TIMEOUT=2000
-  matrix:
-    - 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=OTP-21.1
-    - OTP_RELEASE=maint
-    - OTP_RELEASE=master
+os: linux
+otp_release: 18.0
 
 matrix:
-  fast_finish: true
-  allow_failures:
-    - env: OTP_RELEASE=maint
-    - env: OTP_RELEASE=master
+  include:
+    - os: linux
+      otp_release: 18.1
+    - os: linux
+      otp_release: 18.2
+    - os: linux
+      otp_release: 18.3
+    - os: linux
+      otp_release: 19.0
+    - os: linux
+      otp_release: 19.1
+    - os: linux
+      otp_release: 19.2
+    - os: linux
+      otp_release: 19.3
+    - os: linux
+      otp_release: 20.0
 
-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
+env:
+  - ELIXIR_ASSERT_TIMEOUT=2000
 
 script:
   - make compile
@@ -35,7 +34,6 @@ script:
 
 notifications:
   recipients:
-    - jose.valim@gmail.com
+    - jose.valim@plataformatec.com.br
     - eric.meadows.jonsson@gmail.com
-    - lexmag@me.com
-    - an.leopardi@gmail.com
+

CHANGELOG.md

@@ -1,214 +1,402 @@
-# Changelog for Elixir v1.8
+# Changelog for Elixir v1.5
 
-Elixir v1.8 comes with many improvements at the infrastructure level, improving compilation time, speeding up common patterns, and adding features around introspection of the system.
+Elixir v1.5 brings new features, enhancements and bug fixes to Elixir. It is the first release to leverage features added as part of Erlang/OTP 20. It is also the last release that supports Erlang/OTP 18.
 
-## Custom struct inspections
+## UTF-8 atoms, function names and variables
 
-Elixir now provides a derivable implementation of the `Inspect` protocol. In a nutshell, this means it is really easy to filter data from your data structures whenever they are inspected. For example, imagine you have a user struct with security and privacy sensitive information:
+Elixir v1.5 supports non-quoted atoms and variables to be in UTF-8 when using Erlang/OTP 20+. For example:
 
-```elixir
-defmodule User do
-  defstruct [:id, :name, :age, :email, :encrypted_password]
-end
-```
+    test "こんにちは世界" do
+      assert :こんにちは世界
+    end
 
-By default, if you inspect a user via `inspect(user)`, it will include all fields. This can cause fields such as `:email` and `:encrypted_password` to appear in logs, error reports, etc. You could always define a custom implementation of the `Inspect` protocol for such cases but Elixir v1.8 makes it simpler by allowing you to derive the `Inspect` protocol:
+Or:
 
-```elixir
-defmodule User do
-  @derive {Inspect, only: [:id, :name, :age]}
-  defstruct [:id, :name, :age, :email, :encrypted_password]
-end
-```
+    saudação = "Bom dia!"
 
-Now all user structs will be printed with all remaining fields collapsed:
+Elixir follows the recommendations in [Unicode Annex #31](http://unicode.org/reports/tr31/) to make the language more accessible to other languages and communities. Identifiers must start with a letter or underscore, optionally followed by letters, digits, and underscores. Here letter means any UTF-8 letter-character (optionally with a combining mark) and digit means a UTF-8 decimal-digit-character. If you're using ASCII, this does what you'd expect.
 
-    #User<id: 1, name: "Jane", age: 33, ...>
+Examples of valid variables are:
 
-You can also pass `@derive {Inspect, except: [...]}` in case you want to keep all fields by default and exclude only some.
+    name    josé   _age   まつもと  _42  адрес
+    
+Examples of invalid variables include:
 
-## Time zone database support
+    name•   a±2  42
 
-In Elixir v1.3, Elixir added four types, known as Calendar types, to work with dates and times: `Time`, `Date`, `NaiveDateTime` (without time zone) and `DateTime` (with time zone). Over the last releases we have added many enhancements to the Calendar types but the `DateTime` module always evolved at a slower pace since Elixir did not provide support for a time zone database.
+Symbols, such as mathematical notations and emoji, are not allowed identifiers.
 
-Elixir v1.8 now defines a `Calendar.TimeZoneDatabase` behaviour, allowing developers to bring in their own time zone databases. By defining an explicit contract for time zone behaviours, Elixir can now extend the `DateTime` API, adding functions such as `DateTime.shift_zone/3`. By default, Elixir ships with a time zone database called `Calendar.UTCOnlyTimeZoneDatabase` that only handles UTC.
+For a complete reference on Elixir syntax, see the [Syntax Reference](https://hexdocs.pm/elixir/syntax-reference.html). For technical details on Unicode support, see [Unicode Syntax](https://hexdocs.pm/elixir/unicode-syntax.html).
 
-Other Calendar related improvements include the addition of `Date.day_of_year/1`, `Date.quarter_of_year/1`, `Date.year_of_era/1`, and `Date.day_of_era/1`.
+## IEx improvements
 
-## Faster compilation and other performance improvements
+IEx got many improvements. The autocompletion system is now capable of autocompleting variables and user imports. New helpers have also been added:
 
-Due to improvements to the compiler made over the last year, Elixir v1.8 should compile code about 5% faster on average. This is yet another release where we have been able to reduce compilation times and provide a more joyful development experience to everyone.
+  * `exports/1` lists all exports (functions and macros) in a given module
+  * `open/1` opens up the source of a module or function directly in your editor. For example, `open MyApp.Module`
+  * `runtime_info/0` prints general information about the running system, such as number of cores, runtime version, allocation of memory in the VM and more
 
-The compiler also emits more efficient code for range checks in guards (such as `x in y..z`), for charlists with interpolation (such as `'foo #{bar} baz'`), and when working with records via the `Record` module.
+IEx also features a breakpoint system for code debugging. The following functions have been added to aid debugging:
 
-Finally, EEx templates got their own share of optimizations, emitting more compact code that runs faster.
+  * `break!/2` - sets up a breakpoint for a given `Mod.fun/arity`
+  * `break!/4` - sets up a breakpoint for the given module, function, arity
+  * `breaks/0` - prints all breakpoints and their ids
+  * `continue/0` - continues until the next breakpoint in the same process
+  * `open/0` - opens editor on the current breakpoint
+  * `remove_breaks/0` - removes all breakpoints in all modules
+  * `remove_breaks/1` - removes all breakpoints in a given module
+  * `reset_break/1` - sets the number of stops on the given id to zero
+  * `reset_break/3` - sets the number of stops on the given module, function, arity to zer
+  * `respawn/0` - starts a new shell (breakpoints will ask for permission once more)
+  * `whereami/1` - shows the current location
 
-## Improved instrumentation and ownership with `$callers`
+## Exception.blame
 
-The `Task` module is one of the most common ways to spawn light-weight processes to perform work concurrently. Whenever you spawn a new process, Elixir annotates the parent of that process through the `$ancestors` key. This information can be used by instrumentation tools to track the relationship between events occurring within multiple processes. However, many times, tracking only the `$ancestors` is not enough.
+`Exception.blame/3` is a new function in Elixir that is capable of attaching debug information to certain exceptions. Currently this is used to augment `FunctionClauseError`s with a summary of all clauses and which parts of clause match and which ones didn't. For example:
 
-For example, we recommend developers to always start tasks under a supervisor. This provides more visibility and allows us to control how those tasks are terminated when a node shuts down. In your code, this can be done by invoking something like: `Task.Supervisor.start_child(MySupervisor, task_specification)`. This means that, although your code is the one who invokes the task, the actual parent of the task would be the supervisor, as the supervisor is the one spawning it. We would list the supervisor as one of the `$ancestors` for the task, but the relationship between your code and the task is lost.
+    iex> Access.fetch(:foo, :bar)
+    ** (FunctionClauseError) no function clause matching in Access.fetch/2
 
-In Elixir v1.8, we now track the relationship between your code and the task via the `$callers` key in the process dictionary, which aligns well with the existing `$ancestors` key. Therefore, assuming the `Task.Supervisor` call above, we have:
+    The following arguments were given to Access.fetch/2:
 
-    [your code] -- calls --> [supervisor] ---- spawns --> [task]
+        # 1
+        :foo
 
-which means we store the following relationships:
+        # 2
+        :bar
 
-    [your code]              [supervisor] <-- ancestor -- [task]
-         ^                                                  |
-         |--------------------- caller ---------------------|
+    Attempted function clauses (showing 5 out of 5):
 
-When a task is spawned directly from your code, without a supervisor, then the process running your code will be listed under both `$ancestors` and `$callers`.
+        def fetch(-%struct{} = container-, key)
+        def fetch(map, key) when -is_map(map)-
+        def fetch(list, key) when -is_list(list)- and is_atom(key)
+        def fetch(list, key) when -is_list(list)-
+        def fetch(-nil-, _key)
 
-This small feature is very powerful. It allows instrumentation and monitoring tools to better track and relate the events happening in your system. This feature can also be used by tools like the "Ecto Sandbox". The "Ecto Sandbox" allows developers to run tests concurrently against the database, by using transactions and an ownership mechanism where each process explicitly gets a connection assigned to it. Without `$callers`, every time you spawned a task that queries the database, the task would not know its caller, and therefore it would be unable to know which connection was assigned to it. This often meant features that relies on tasks could not be tested concurrently. With `$callers`, figuring out this relationship is trivial and you have more tests using the full power of your machine.
+    (elixir) lib/access.ex:261: Access.fetch/2
 
-## v1.8.2 (2019-05-11)
+In the example above, an argument that did not match or guard that did not evaluate to true are shown between `-`. If the terminal supports ANSI coloring, they are wrapped in red instead of the `-` character.
 
-### 1. Bug fixes
+Since blaming an exception can be expensive, `Exception.blame/3` must be used exclusively in debugging situations. It is not advised to apply it to production components such as a Logger. This feature has been integrated into the compiler, the command line, ExUnit and IEx.
 
-#### EEx
+This feature also requires Erlang/OTP 20+.
 
-  * [EEx] Raise readable error message on bad EEx state
+## Streamlined child specs
 
-#### Elixir
+Elixir v1.5 streamlines how supervisors are defined and used in Elixir. Elixir now allows child specifications, which specify how a child process is supervised, to be defined in modules. In previous versions, a project using Phoenix would write:
 
-  * [Protocol] Ensure `:debug_info` is kept in protocols
+    import Supervisor.Spec
 
-#### Logger
+    children = [
+      supervisor(MyApp.Repo, []),
+      supervisor(MyApp.Endpoint, [])
+    ]
 
-  * [Logger] Make sure Logger v1.8 does not get stuck in discard mode
-  * [Logger.Translator] Translate remote process crash in Logger
+    Supervisor.start_link(children, strategy: :one_for_one)
 
-## v1.8.1 (2019-01-30)
+In Elixir v1.5, one might do:
+
+    children = [
+      MyApp.Repo,
+      MyApp.Endpoint
+    ]
+
+    Supervisor.start_link(children, strategy: :one_for_one)
+
+The above works by calling the `child_spec/1` function on the given modules.
+
+This new approach allows `MyApp.Repo` and `MyApp.Endpoint` to control how they run under a supervisor. This reduces the chances of mistakes being made, such as starting an Ecto repository as a worker or forgetting to declare that tasks are temporary in a supervision tree.
+
+If it is necessary to configure any of the children, such can be done by passing a tuple instead of an atom:
+
+    children = [
+      {MyApp.Repo, url: "ecto://localhost:4567/my_dev"},
+      MyApp.Endpoint
+    ]
+
+The modules `Agent`, `Registry`, `Task`, and `Task.Supervisor` have been updated to include a `child_spec/1` function, allowing them to be used directly in a supervision tree similar to the examples above. `use Agent`, `use GenServer`, `use Supervisor`, and `use Task` have also been updated to automatically define an overridable `child_spec/1` function.
+
+Finally, child specifications are now provided as maps (data-structures) instead of the previous `Supervisor.Spec.worker/3` and `Supervisor.Spec.supervisor/3` APIs. This behaviour also aligns with how supervisors are configured in Erlang/OTP 18+. See the updated `Supervisor` docs for more information, as well as the new `Supervisor.init/2` and `Supervisor.child_spec/2` functions.
+
+## @impl
+
+This release also allows developers to mark which functions in a given module are an implementation of a callback. For example, when using the [Plug](https://github.com/elixir-lang/plug) project, one needs to implement both `init/1` and `call/2` when writing a Plug:
+
+    defmodule MyApp do
+      @behaviour Plug
+
+      def init(_opts) do
+        opts
+      end
+
+      def call(conn, _opts) do
+        Plug.Conn.send_resp(conn, 200, "hello world")
+      end
+    end
+
+The problem with the approach above is that, once more and more functions are added to the `MyApp` module, it becomes increasingly harder to know the purposes of the `init/1` and `call/2` functions. For example, for a developer unfamiliar with Plug, are those functions part of the `MyApp` API or are they implementations of a given callback?
+
+Elixir v1.5 introduces the `@impl` attribute, which allows us to mark that certain functions are implementation of callbacks:
+
+    defmodule MyApp do
+      @behaviour Plug
+
+      @impl true
+      def init(_opts) do
+        opts
+      end
+
+      @impl true
+      def call(conn, _opts) do
+        Plug.Conn.send_resp(conn, 200, "hello world")
+      end
+    end
+
+You may even use `@impl Plug` if you want to explicitly document which behaviour defines the callback you are implementing.
+
+Overall, using `@impl` has the following advantages:
+
+  * Readability of the code is increased, as it is now clear which functions are part of your API and which ones are callback implementations. To reinforce this idea, `@impl true` automatically marks the function as `@doc false`, disabling documentation unless `@doc` is explicitly set
+
+  * If you define `@impl` before a function that is not a callback, Elixir will error. This is useful in case of typos or in case the behaviour definition changes (such as a new major version of a library you depend on is released)
+
+  * If you use `@impl` in one implementation, Elixir will force you to declare `@impl` for all other implementations in the same module, keeping your modules consistent
+
+## Calendar improvements
+
+This release brings further improvements to Calendar types. It adds arithmetic and others functions to `Time`, `Date`, `NaiveDateTime` and `Datetime` as well as conversion between different calendars.
+
+## v1.5.3 (2017-12-19)
 
 ### 1. Bug fixes
 
 #### Elixir
 
-  * [Float] Fix rounding for subnormal floats
-
-#### IEx
-
-  * [IEx] Fix `IEx.pry` crash when IEx isn't running
-  * [IEx.CLI] Add IEx warning when using `--remsh` with dumb terminal
-  * [IEx.Helpers] Sort results by arity on `h` helper
-
-#### Mix
-
-  * [mix compile] Do not include optional dependencies in extra applications as it is incompatible with shared deps in umbrellas
-
-## v1.8.0 (2019-01-14)
-
-### 1. Enhancements
-
-#### EEx
-
-  * [EEx] Optimize the default template engine to compile and execute more efficiently
-
-#### Elixir
-
-  * [Calendar] Add `Calendar.TimeZoneDatabase` and a `Calendar.UTCOnlyTimeZoneDatabase` implementation
-  * [Calendar] Add callbacks `day_of_year/3`, `quarter_of_year/3`, `year_of_era/1`, and `day_of_era/3`
-  * [Code.Formatter] Preserve user's choice of new line after most operators
-  * [Date] Add `Date.day_of_year/1`, `Date.quarter_of_year/1`, `Date.year_of_era/1`, and `Date.day_of_era/1`
-  * [DateTime] Add `DateTime.from_naive/3`, `DateTime.now/1`, and `DateTime.shift_zone/3`
-  * [File] Allow `:raw` option in `File.exists?/2`, `File.regular?/2`, and `File.dir?/2`
-  * [File] Allow POSIX time as an integer in `File.touch/2` and `File.touch!/2`
-  * [Inspect] Allow `Inspect` protocol to be derivable with the `:only`/`:except` options
-  * [Kernel] Do not propagate counters to variables in quote inside another quote
-  * [Kernel] Warn on ambiguous use of `::` and `|` in typespecs
-  * [Kernel] Add `:delegate_to` `@doc` metadata tag when using `defdelegate`
-  * [Kernel] Improve compile-time building of ranges via the `..` operator
-  * [Kernel] Compile charlist interpolation more efficiently
-  * [Kernel] Add `floor/1` and `ceil/1` guards
-  * [Kernel.SpecialForms] Add `:reduce` option to `for` comprehensions
-  * [List] Add `List.myers_difference/3` and `List.improper?/1`
-  * [Macro] Add `Macro.struct!/2` for proper struct resolution during compile time
-  * [Map] Optimize and merge nested maps `put` and `merge` operations
-  * [Range] Add `Range.disjoint?/2`
-  * [Record] Reduce memory allocation when updating multiple fields in a record
-  * [Registry] Allow associating a value on `:via` tuple
-  * [String] Add `String.bag_distance/2`
-  * [Task] Add `$callers` tracking to `Task` - this makes it easier to find which process spawned a task and use it for tracking ownership and monitoring
+  * [Calendar] Consider microseconds in maximum possible Calendar.ISO datetime
+  * [Enum] Fix `chunk_every/4` when `step > count`
+  * [Kernel] Warn duplicate definitions in macros
+  * [Kernel] Remove dialyzer warnings from else in with clauses
+  * [Kernel] Do not warning on upcoming `@deprecated` and `@since` attributes for v1.6
+  * [MapSet] Return valid MapSet when union-ing a legacy MapSet
 
 #### ExUnit
 
-  * [ExUnit] Add `ExUnit.after_suite/1` callback
-  * [ExUnit.Assertions] Show last N messages (instead of first N) from mailbox on `assert_receive` fail
+  * [ExUnit] Fix compiler warnings in `assert_receive/3`
 
-#### IEx
+## v1.5.2 (2017-09-29)
 
-  * [IEx.Helpers] Add `port/1` and `port/2`
-  * [IEx.Server] Expose `IEx.Server.run/1` for custom IEx sessions with the ability to broker pry sessions
+### 1. Enhacements
 
-#### Mix
+#### Elixir
 
-  * [Mix] Add `Mix.target/0` and `Mix.target/1` to control dependency management per target
-  * [Mix.Project] Add `:depth` and `:parents` options to `deps_paths/1`
-  * [mix archive.install] Add a timeout when installing archives
-  * [mix compile] Include optional dependencies in `:extra_applications`
-  * [mix escript.install] Add a timeout when installing escripts
-  * [mix format] Warn when the same file may be formatted by multiple `.formatter.exs`
-  * [mix test] Allow setting the maximum number of failures via `--max-failures`
-  * [mix test] Print a message instead of raising on unmatched tests inside umbrella projects
+  * [Kernel] Optimize function definition with multiple clauses by not traversing the internal clauses table
+  * [Kernel] Warn if unary operators are followed by new lines
+  * [Registry] Use the name of the Registry as its `:id` in the `child_spec/1` function
 
 ### 2. Bug fixes
 
 #### Elixir
 
-  * [Calendar] Allow printing dates with more than 9999 years
-  * [Exception] Exclude deprecated functions in "did you mean?" hints
-  * [Float] Handle subnormal floats in `Float.ratio/1`
-  * [Kernel] Remove `Guard test tuple_size(...) can never succeed` Dialyzer warning on `try`
-  * [Kernel] Expand operands in `size*unit` bitstring modifier instead of expecting `size` and `unit` to be literal integers
-  * [Kernel] Do not deadlock on circular struct dependencies in typespecs
-  * [Kernel] Raise proper error message when passing flags to the Erlang compiler that Elixir cannot handle
-  * [Kernel] Do not leak variables in `cond` clauses with a single matching at compile-time clause
-  * [NaiveDateTime] Do not accept leap seconds in builder and parsing functions
-  * [String] Fix ZWJ handling in Unicode grapheme clusters
-  * [StringIO] Handle non-printable args in StringIO gracefully
+  * [DateTime] Fix negative microsecond result when passing negative Unix epochs to `from_unix/2`
+  * [Kernel] Improve error message for oversized atoms
+  * [Kernel] Ensure `@impl` attribute also propagates to clauses from default arguments
+  * [Kernel] Emit proper error for unknown vars inside binary pattern in match
 
 #### IEx
 
-  * [IEx.Helpers] Use typespec info (instead of docs chunk) and properly format callbacks in `b/1`
-
-#### Logger
-
-  * [Logger] Allow Logger backends to be dynamically removed when an application is shutting down
+  * [IEx] Do not crash IEx unexpectedly on `System.stop/0`
+  * [IEx.Helpers] Ensure exiting a breakpoint set inside a breakpoint does not terminate the shell unexpectedly
 
 #### Mix
 
-  * [mix compile] Ensure changes in deps propagate to all umbrella children - this fix a long standing issue where updating a dependency would not recompile all projects accordingly, requiring a complete removal of `_build`
-  * [mix compile] Avoid time drift when checking and updating compiler manifest files
-  * [mix compile.app] Respect the `:only` option between umbrella siblings
-  * [mix compile.protocols] Reconsolidate protocols if local dependencies are stale
-  * [mix deps] Properly mark dependencies with different `:system_env` as diverged
-  * [mix new] Use `--module` value when setting up filenames
+  * [mix local.hex] Ensure `--if-missing` flag works as advertised
+  * [mix test] Do not trigger additional error reports when there is a failure when loading test files
+  * [Mix.SCM.Git] Ensure errors when invoking `git` propagate correctly
 
-### 3. Soft-deprecations (no warnings emitted)
+## v1.5.1 (2017-08-01)
 
-None.
+### 1. Enhancements
 
-### 4. Hard-deprecations
+#### EEx
+
+  * [EEx.Engine] Add `handle_begin` and `handle_end` to EEx
 
 #### Elixir
 
-  * [Enum] Passing a non-empty list to `Enum.into/2` was inconsistent with maps and is deprecated in favor of `Kernel.++/2` or `Keyword.merge/2`
-  * [Inspect.Algebra] `surround/3` is deprecated in favor of `Inspect.Algebra.concat/2` and `Inspect.Algebra.nest/2`
-  * [Inspect.Algebra] `surround_many/6` is deprecated in favor of `container_doc/6`
-  * [Kernel] Using `@since` will now emit a unused attribute warning. Use `@doc since: "1.7.2"` instead
-  * [Kernel] Passing a non-empty list as `:into` in `for` comprehensions was inconsistent with maps and is deprecated in favor of `Kernel.++/2` or `Keyword.merge/2`
-  * [Kernel.ParallelCompiler] `files/2` is deprecated in favor of `compile/2`
-  * [Kernel.ParallelCompiler] `files_to_path/2` is deprecated in favor of `compile_to_path/2`
-  * [Kernel.ParallelRequire] `files/2` is deprecated in favor of `Kernel.ParallelCompiler.require/2`
-  * [System] `:seconds`, `:milliseconds`, etc. as time units is deprecated in favor of `:second`, `:millisecond`, etc.
-  * [System] `System.cwd/0` and `System.cwd!/0` are deprecated in favor of `File.cwd/0` and `File.cwd!/0`
+  * [Kernel] Do not use references on function/macro definitions - this provides large improvements in compilation times in some rare corner cases
+  * [Supervisor] Support mixing old and new typespecs in `Supervisor.init/2` and `Supevisor.start_link/2`
 
 #### Mix
 
-  * [mix compile.erlang] Returning `{:ok, contents}` or `:error` as the callback in `Mix.Compilers.Erlang.compile/6` is deprecated in favor of returning `{:ok, contents, warnings}` or `{:error, errors, warnings}`
+  * [mix profile] Allow profile tasks to run without a project
 
-## v1.7
+### 2. Bug fixes
 
-The CHANGELOG for v1.7 releases can be found [in the v1.7 branch](https://github.com/elixir-lang/elixir/blob/v1.7/CHANGELOG.md).
+#### EEx
+
+  * [EEx.Engine] Do not re-use the value of the `init/1` callback throughout the compilation stack
+
+#### Elixir
+
+  * [Kernel] Ensure dialyzer does not emit warnings in some uses of `with`
+  * [Kernel] Fix dialyzer warnings when `defmacrop` is used in modules
+  * [Kernel] Ensure Elixir modules can be dialyzed without starting the Elixir application
+  * [Kernel] Do not serialize references in quoted expressions
+  * [Kernel] Make sure structs expansion use the latest definition available when struct modules are recompiled
+  * [Task] Support `:infinity` timeout on Task streams
+  * [Typespec] Ensure typespecs allow `tuple` to be used as variable names
+
+## v1.5.0 (2017-07-25)
+
+### 1. Enhancements
+
+#### Elixir
+
+  * [Access] Optimize `Access.get/2`
+  * [Base] Optimise Base encode/decode
+  * [Calendar] Implement Inspect for DateTime with Calendar.ISO
+  * [Calendar] Add "ISO days" format for conversions between Calendars and `Date.convert/2`, `Time.convert/2`, `NaiveDateTime.convert/2` and `DateTime.convert/2` (as well as bang variants)
+  * [Calendar] Add `:calendar` field to `Time` struct
+  * [Calendar] Add `Time.diff/3`, `Date.add/2`, `Date.diff/2`, `DateTime.diff/3`
+  * [Calendar] Add `Date.range/2`
+  * [Calendar] Add `Date.new/4`, `DateTime.utc_now/1`, `NaiveDateTime.new/8` and `Time.new/5` that allow specifing calendar
+  * [Enum] Add `Enum.chunk_by/4` and `Stream.chunk_by/4`
+  * [Enum] Add `Enum.chunk_every/2` and `Enum.chunk_every/4` with a more explicit API than `Enum.chunk/2` and `Enum.chunk/4`
+  * [Exception] Add `Exception.blame/3` that adds metadata to exceptions
+  * [File] Add `File.read_link/1` and `File.read_link!/1`
+  * [File] Introduce `:trim_bom` option for `File.stream!/2`
+  * [Inspect] Add `:printable_limit` to control the limit of printable structures
+  * [Integer] Add `Integer.gcd/2`
+  * [Kernel] Add `left not in right` to check that the left side is not in the enumerable on the right
+  * [Kernel] Use the new `debug_info` chunk in OTP 20. This provides a mechanism for tools to retrieve the Elixir AST from beam files
+  * [Kernel] `defoverridable/1` accepts a module name as argument and marks all callbacks as overridable
+  * [Kernel] Allow non-quoted Unicode atoms and variables according to Unicode Annex #31 (see Unicode Syntax document)
+  * [Kernel] Warn when a `:__struct__` key is used when building/updating structs
+  * [Kernel] Cache the AST on definitions. This speeds up the compilation time from 10% to 15% measured across different projects
+  * [Kernel] Improve compiler error message on invalid patterns and guards
+  * [Keyword] Add `replace/3` and `replace!/3` for replacing an existing key
+  * [List] `List.starts_with?/2`
+  * [Macro] Introduce `Macro.generate_arguments/2`
+  * [Map] Optimize `Map.merge/3` by choosing merging direction
+  * [Map] Add `replace/3` and `replace!/3` for replacing an existing key
+  * [Map] Raise `BadMapError` in `Map.equal?/2` when either of the two arguments is not a map
+  * [MapSet] Reduce `MapSet` size when serialized to approximately half
+  * [Process] Add `Process.cancel_timer/2`
+  * [Protocol] Show available implementations on `Protocol.UndefinedError` if the protocol has been consolidated
+  * [Registry] Support ETS guard conditions in `Registry.match/3`
+  * [Registry] Support `parallel: true` in `Registry.dispatch/3`
+  * [Registry] Introduce `Registry.unregister_match/4`
+  * [Stream] Add `Stream.chunk_every/2` and `Stream.chunk_every/4` with a more explicit API than `Stream.chunk/2` and `Stream.chunk/4`
+  * [String] Optimise binary pattern matching in `String.split/1` and `String.trim_*/1`
+  * [Supervisor] Add `Supervisor.init/2` and `Supervisor.child_spec/2`
+  * [Supervisor] Allow `module` and `{module, arg}` to be given to `Supervisor.start_link/2` and invoke `module.child_spec(arg)` on each argument
+  * [Task] Support `:on_timeout` in `Task.async_stream` to control how tasks are terminated
+  * [Task] Add `ordered: false` support to `Task.async_stream`
+
+#### ExUnit
+
+  * [ExUnit] Show code snippet from test source file in case of test errors
+  * [ExUnit] Use `Exception.blame/3` when formatting test errors
+  * [ExUnit] Make `assert_raise/2` fail if the underlying exception has a broken `message/1` implementation
+  * [ExUnit] Add `start_supervised/2` and `stop_supervised/1` to ExUnit. Processes started by this function are automatically shut down when the test exits
+
+#### IEx
+
+  * [IEx.Autocomplete] Support autocompletion of variable names
+  * [IEx.Autocomplete] Support autocompletion of functions imported using `import Mod, only: [...]`
+  * [IEx.Evaluator] Use `Exception.blame/3` when showing errors in the terminal
+  * [IEx.Helpers] Add `exports/1` IEx helper to list all exports in a module
+  * [IEx.Helpers] Add `break!/2`, `break!/4`, `breaks/0`, `continue/0`, `open/0`, `remove_breaks/0`, `remove_breaks/1`, `reset_break/1`, `reset_break/3` and `whereami/1` for code debugging
+  * [IEx.Helpers] No longer emit warnings for IEx commands without parentheses
+  * [IEx.Helpers] Add `runtime_info/0` for printing runtime system information
+  * [IEx.Helpers] Add `open/1` to open the source of a given module/function in your editor
+  * [IEx.Info] Implement `IEx.Info` protocol for calendar types
+
+#### Logger
+
+  * [Logger] Add `metadata: :all` configuration to log all metadata
+
+#### Mix
+
+  * [mix compile.elixir] Add `--all-warnings` option to Elixir compiler that shows all warnings from the previous compilation (instead of just of the files being compiled)
+  * [mix escript.build] Strip debug information from escripts by default and add option `:strip_beam` which defaults to true
+  * [mix loadpaths] Ensure `--no-deps-check` do not trigger SCM callbacks (such as `git`)
+  * [mix local.hex] Add `--if-missing` flag to `local.hex` mix task
+  * [mix profile.cprof] Add `Mix.Tasks.Profile.Cprof` for count-based profiling
+  * [mix new] New styling for generated applications
+
+### 2. Bug fixes
+
+#### Elixir
+
+  * [Calendar] Ensure `Calendar.ISO` raises a readable error when reaching up the year 10000 restriction
+  * [Calendar] Return `{:error, :invalid_time}` for wrong precision instead of crashing when parsing ISO dates
+  * [Enumerable] Raise `Protocol.UndefinedError` on bad functions in Enumerable implementation
+  * [File] Ensure recursive file operations raise on paths with null bytes (*security issue reported by Griffin Byatt*)
+  * [File] Support `:ram`/`:raw` files in `File.copy/2`
+  * [Inspect] Do not use colors when inspecting error messages
+  * [Kernel] Support guards on anonymous functions of zero arity
+  * [Kernel] Fix compilation of maps used as maps keys inside matches
+  * [Kernel] Ensure `do` clause in `with` is tail call optimizable
+  * [Module] `on_definition/6` callback receives body wrapped in a keyword list, such as `[do: body]`. This solves a bug where it was impossible to distinguish between a bodyless clause and a function that returns `nil`.
+  * [Path] Ensure recursive path operations raise on paths with null bytes (*security issue reported by Griffin Byatt*)
+  * [Protocol] Do not lose source compile info on protocol consolidation
+  * [Record] Properly escape quoted expressions passed to `defrecord`
+  * [Regex] Fix `inspect/2` for regexes with `/` terminator in them
+  * [Registry] Ensure `Registry.match/4` works with `:_` as key
+  * [Stream] Fix stream cycle over empty enumerable
+  * [String] Consider Unicode non-characters valid according to the specification in `String.valid?/1`
+  * [StringIO] Fix encoding and performance issues in `StringIO.get_until`
+  * [System] Raise on paths with null bytes in `System.cmd/2` and in `System.find_executable/1` (*security issue reported by Griffin Byatt*)
+  * [System] Raise on ill-formed environment variables (*security issue reported by Griffin Byatt*)
+
+#### ExUnit
+
+  * [ExUnit] Properly account failed tests when `setup_all` fails
+  * [ExUnit] Having two or more `describe` blocks with the same name will now raise an error.
+
+#### IEx
+
+  * [IEx] Skip autocompletion of module names that are invalid without being quoted
+  * [IEx] Skip autocompletion of functions with default arguments with `@doc false`
+  * [IEx] Do not start oldshell alongside IEx
+
+#### Mix
+
+  * [mix compile.elixir] Store multiple sources in case of module conflicts. This solves an issue where `_build` would get corrupted when compiling Elixir projects with module conflicts
+  * [mix compile.erlang] Do not silently discard Erlang compile errors
+  * [mix compile.erlang] Properly track `-compile` module attribute when specified as a list
+  * [mix compile.protocols] Ensure protocol implementations do not "disappear" when switching between applications in umbrella projects by having separate consolidation paths per project
+  * [mix compile.protocols] Do not raise when consolidating a protocol that was converted into a module
+
+### 3. Soft deprecations (no warnings emitted)
+
+#### Elixir
+
+  * [Kernel] `not left in right` is soft-deprecated in favor of `left not in right`
+
+### 4. Deprecations
+
+#### Elixir
+
+  * `Atom.to_char_list/1`, `Float.to_char_list/1`, `Integer.to_char_list/1`, `Integer.to_char_list/2`, `Kernel.to_char_list/1`, `List.Chars.to_char_list/1`, `String.to_char_list/1` have been deprecated in favor of their `to_charlist` version. This aligns with the naming conventions in both Erlang and Elixir
+  * [Enum] Deprecate `Enum.filter_map/3` in favor of `Enum.filter/2` + `Enum.map/2` or for-comprehensions
+  * [GenEvent] Deprecate `GenEvent` and provide alternatives in its docs
+  * [Kernel] Using `()` to mean `nil` is deprecated
+  * [Kernel] `:as_char_lists value` in `Inspect.Opts.t/0` type, in favor of `:as_charlists`
+  * [Kernel] `:char_lists` key in `Inspect.Opts.t/0` type, in favor of `:charlists`
+  * [Module] Using Erlang parse transforms via `@compile {:parse_transform, _}` is deprecated
+  * [Stream] Deprecate `Stream.filter_map/3` in favor of `Stream.filter/2` + `Stream.map/2`
+  * [String] `String.ljust/3` and `String.rjust/3` are deprecated in favor of `String.pad_leading/3` and `String.pad_trailing/3` with a binary padding
+  * [String] `String.strip/1` and `String.strip/2` are deprecated in favor of `String.trim/1` and `String.trim/2`
+  * [String] `String.lstrip/1` and `String.rstrip/1` are deprecated in favor of `String.trim_leading/1` and `String.trim_trailing/1`
+  * [String] `String.lstrip/2` and `String.rstrip/2` are deprecated in favor of `String.trim_leading/2` and `String.trim_trailing/2` with a binary as second argument
+  * [Typespec] `char_list/0` type is deprecated in favor of `charlist/0`
+
+#### EEx
+
+  * [EEx] Deprecate `<%= ` in "middle" and "end" expressions, e.g.: `<%= else %>` and `<%= end %>`
+
+## v1.4
+
+The CHANGELOG for v1.4 releases can be found [in the v1.4 branch](https://github.com/elixir-lang/elixir/blob/v1.4/CHANGELOG.md).

ISSUE_TEMPLATE.md

@@ -1,14 +1,13 @@
 ### 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: https://groups.google.com/group/elixir-lang-core
+* 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
-* Please disclose security vulnerabilities privately at elixir-security@googlegroups.com
 * Finally, be nice and have fun!
 
 ### Environment
 
-* Elixir & Erlang/OTP versions (elixir --version): 
+* Elixir & Erlang versions (elixir --version): 
 * Operating system: 
 
 ### Current behavior
@@ -17,4 +16,3 @@ Include code samples, errors and stacktraces if appropriate.
 
 ### Expected behavior
 
-A short description on how you expect the code to behave.

LICENSE

@@ -1,176 +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
 
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-      direction or management of such entity, whether by contract or
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+  Unless required by applicable law or agreed to in writing, software
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Makefile

@@ -1,11 +1,10 @@
+REBAR ?= "$(CURDIR)/rebar"
 PREFIX ?= /usr/local
 SHARE_PREFIX ?= $(PREFIX)/share
-MAN_PREFIX ?= $(SHARE_PREFIX)/man
-CANONICAL := v1.8/ # master/ or vMAJOR.MINOR/
-ELIXIRC := bin/elixirc --verbose --ignore-module-conflict --warnings-as-errors
-ERLC := erlc -I lib/elixir/include +warnings_as_errors
+CANONICAL := v1.5/
+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
@@ -17,24 +16,28 @@ 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 clean_residual_files install_man clean_man docs Docs.zip Precompiled.zip zips
 .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 >= 20)])' -s erlang halt | grep -q '^true'; \
+	$(Q) erl -noshell -eval '{V,_} = string:to_integer(erlang:system_info(otp_release)), io:fwrite("~s", [is_integer(V) and (V >= 18)])' -s erlang halt | grep -q '^true'; \
 		if [ $$? != 0 ]; then \
-		  echo "At least Erlang/OTP 20.0 is required to build Elixir"; \
+		  echo "At least Erlang 18.0 is required to build Elixir"; \
 		  exit 1; \
-		fi
+		fi;
 endef
 
 define APP_TEMPLATE
 $(1): lib/$(1)/ebin/Elixir.$(2).beam lib/$(1)/ebin/$(1).app
 
 lib/$(1)/ebin/$(1).app: lib/$(1)/mix.exs
-	$(Q) cd lib/$(1) && ../../bin/elixir -e 'Mix.start(:permanent, [])' -r mix.exs -e 'Mix.Task.run("compile.app", ~w[--compile-path ebin])'
+	$(Q) mkdir -p lib/$(1)/_build/shared/lib/$(1)
+	$(Q) cp -R lib/$(1)/ebin lib/$(1)/_build/shared/lib/$(1)/
+	$(Q) cd lib/$(1) && ../../bin/elixir -e 'Mix.start(:permanent, [])' -r mix.exs -e 'Mix.Task.run("compile.app")'
+	$(Q) cp lib/$(1)/_build/shared/lib/$(1)/ebin/$(1).app lib/$(1)/ebin/$(1).app
+	$(Q) rm -rf lib/$(1)/_build
 
 lib/$(1)/ebin/Elixir.$(2).beam: $(wildcard lib/$(1)/lib/*.ex) $(wildcard lib/$(1)/lib/*/*.ex) $(wildcard lib/$(1)/lib/*/*/*.ex)
 	@ echo "==> $(1) (compile)"
@@ -42,31 +45,32 @@ lib/$(1)/ebin/Elixir.$(2).beam: $(wildcard lib/$(1)/lib/*.ex) $(wildcard lib/$(1
 	$(Q) cd lib/$(1) && ../../$$(ELIXIRC) "lib/**/*.ex" -o ebin
 
 test_$(1): compile $(1)
-	@ echo "==> $(1) (ex_unit)"
+	@ echo "==> $(1) (exunit)"
 	$(Q) cd lib/$(1) && ../../bin/elixir -r "test/test_helper.exs" -pr "test/**/*_test.exs";
 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 -f 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
+# then mix and then compile EEx fully
 elixir: stdlib lib/eex/ebin/Elixir.EEx.beam mix ex_unit logger eex iex
 
 stdlib: $(KERNEL) VERSION
@@ -79,11 +83,8 @@ $(KERNEL): lib/elixir/lib/*.ex lib/elixir/lib/*/*.ex lib/elixir/lib/*/*/*.ex
 	$(Q) cd lib/elixir && ../../$(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 -f lib/elixir/ebin/elixir.app
+	$(Q) cd lib/elixir && $(REBAR) compile
 
 unicode: $(UNICODE)
 $(UNICODE): lib/elixir/unicode/*
@@ -114,9 +115,10 @@ install: compile
 	$(MAKE) install_man
 
 clean:
+	cd lib/elixir && $(REBAR) clean
 	rm -rf ebin
 	rm -rf lib/*/ebin
-	rm -rf $(PARSER)
+	rm -f lib/elixir/src/elixir.app.src
 	$(Q) $(MAKE) clean_residual_files
 
 clean_elixir:
@@ -138,14 +140,14 @@ clean_residual_files:
 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 https://elixir-lang.org/docs.html -f "$(DOCS_FORMAT)" $(4)
+COMPILE_DOCS = bin/elixir ../ex_doc/bin/ex_doc "$(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)
 
 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/Behaviours.md" -e "lib/elixir/pages/Deprecations.md" -e "lib/elixir/pages/Guards.md" -e "lib/elixir/pages/Naming Conventions.md" -e "lib/elixir/pages/Operators.md" -e "lib/elixir/pages/Syntax Reference.md" -e "lib/elixir/pages/Typespecs.md" -e "lib/elixir/pages/Unicode Syntax.md" -e "lib/elixir/pages/Writing Documentation.md")
 
 docs_eex: compile ../ex_doc/bin/ex_doc
 	@ echo "==> ex_doc (eex)"
@@ -185,22 +187,14 @@ Docs.zip: docs
 
 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
+	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 ""
 
 #==> Test tasks
 
-test: test_formatted test_erlang test_elixir
+test: test_erlang test_elixir
 
 test_windows: test test_taskkill
 
@@ -212,9 +206,6 @@ 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;
@@ -227,7 +218,7 @@ $(TEST_EBIN)/%.beam: $(TEST_ERL)/%.erl
 test_elixir: test_stdlib test_ex_unit test_logger test_mix test_eex test_iex
 
 test_stdlib: compile
-	@ echo "==> elixir (ex_unit)"
+	@ echo "==> elixir (exunit)"
 	$(Q) exec epmd & exit
 	$(Q) if [ "$(OS)" = "Windows_NT" ]; then \
 		cd lib/elixir && cmd //C call ../../bin/elixir.bat -r "test/elixir/test_helper.exs" -pr "test/elixir/**/*_test.exs"; \
@@ -251,7 +242,7 @@ build_plt: clean_plt $(PLT)
 
 dialyze: compile $(PLT)
 	@ echo "==> Dialyzing Elixir..."
-	$(Q) dialyzer -pa lib/elixir/ebin --plt $(PLT) $(DIALYZER_OPTS) lib/*/ebin
+	$(Q) dialyzer --plt $(PLT) $(DIALYZER_OPTS) lib/*/ebin
 
 #==> Man page tasks
 
@@ -259,13 +250,13 @@ 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
 
 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
 
@@ -276,9 +267,9 @@ clean_man:
 	rm -f man/iex.1.bak
 
 install_man: build_man
-	$(Q) mkdir -p $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/elixir.1  $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/elixirc.1 $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/iex.1     $(DESTDIR)$(MAN_PREFIX)/man1
-	$(Q) $(INSTALL_DATA) man/mix.1     $(DESTDIR)$(MAN_PREFIX)/man1
+	$(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
 	$(MAKE) clean_man

NOTICE

@@ -1,7 +1,9 @@
 LEGAL NOTICE INFORMATION
 ------------------------
 
-All the files in this distribution are copyright to the terms below.
+All the files in this distribution are copyright (c) 2012 Plataformatec
+covered under Elixir's license (see the file LICENSE) except the cases
+below.
 
 == lib/elixir/src/elixir_parser.erl (generated by build scripts)
 
@@ -18,19 +20,3 @@ 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.
-
-== All other files
-
-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.

README.md

@@ -2,16 +2,13 @@
 =========
 [![Travis build](https://secure.travis-ci.org/elixir-lang/elixir.svg?branch=master
 "Build Status")](https://travis-ci.org/elixir-lang/elixir)
+[![Windows build](https://ci.appveyor.com/api/projects/status/macwuxq7aiiv61g1?svg=true)](https://ci.appveyor.com/project/josevalim/elixir)
 
-Elixir is a dynamic, functional language designed for building scalable
-and maintainable applications.
+
+Elixir is a dynamic, functional language designed for building scalable and maintainable applications.
 
 For more about Elixir, installation and documentation,
-[check Elixir's website](https://elixir-lang.org/).
-
-## Announcements
-
-New releases are announced in the [announcements mailing list](https://groups.google.com/group/elixir-lang-ann). All security releases [will be tagged with `[security]`](https://groups.google.com/forum/#!searchin/elixir-lang-ann/%5Bsecurity%5D%7Csort:date).
+[check Elixir's website](http://elixir-lang.org/).
 
 ## Compiling from source
 
@@ -34,11 +31,11 @@ If Elixir fails to build (specifically when pulling in a new version via
 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 20.0 or later). You can check your Erlang/OTP version
+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 20 [erts-9.0] [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.
@@ -46,33 +43,14 @@ 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].
+for reporting a new issue. Please disclose security vulnerabilities
+privately at elixir-security@googlegroups.com.
 
 ## 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:
+We welcome 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
 
@@ -89,9 +67,10 @@ in applications inside the `lib` folder:
 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`.
+library, you can run only that portion through `make test_stdlib`, as
+`test_elixir` also runs tests for the other projects (EEx, ExUnit, etc.).
 
-If you are changing just one file, you can choose to compile and run tests only
+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:
 
@@ -106,30 +85,44 @@ To recompile (including Erlang modules):
 make compile
 ```
 
-After your changes are done, please remember to run `mix format` to guarantee
-all files are properly formatted and then run the full suite with
-`make test`.
-
-If your contribution fails during the bootstrapping of the language,
-you can rebuild the language from scratch with:
+If your contribution fails the build during the bootstrapping of the language,
+you can reproduce it locally by deleting all of Elixir beam files and compiling
+again:
 
 ```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).
+Or to rebuild everything from scratch without running tests:
+
+```sh
+make clean compile
+```
+
 More tasks can be found by reading the [Makefile](./Makefile).
 
+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 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)
+* [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)
+
+We usually keep a list of enhancements and bugs [in the issue tracker][2].
+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. Finally, remember all interactions in our official
+spaces follow our [Code of Conduct][7].
 
 ### Reviewing changes
 
@@ -137,22 +130,15 @@ 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 repository. In case any changes are necessary, the team will leave
+appropriate comments requesting changes to the code.
 
 The Elixir team may optionally assign someone to review a pull request.
-If someone is assigned, they must explicitly approve the code before
+In case 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.
+When review is completed, your pull request will be squashed and merged
+into the repository.
 
 ## Building documentation
 
@@ -166,25 +152,25 @@ cd ex_doc && ../elixir/bin/mix do deps.get, compile
 cd ../elixir && make docs
 ```
 
-This will produce documentation sets for `elixir`, `mix`, etc. under
+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).
 
 ## Development links
 
-  * [Elixir Getting Started guide][1]
+  * [Elixir Website][1]
   * [Elixir Documentation][6]
   * [Elixir Core Mailing list (development)][3]
   * [Issues tracker][2]
   * [Code of Conduct][7]
   * **[#elixir-lang][4]** on [Freenode][5] IRC
 
-  [1]: https://elixir-lang.org/getting-started/introduction.html
+  [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]: https://elixir-lang.org/docs.html
+  [6]: http://elixir-lang.org/docs.html
   [7]: CODE_OF_CONDUCT.md
 
 ## License
@@ -193,4 +179,5 @@ the `doc` directory. If you are planning to contribute documentation,
 
 Elixir source code is released under Apache 2 License.
 
-Check [NOTICE](NOTICE) and [LICENSE](LICENSE) files for more information.
+Check [NOTICE](NOTICE) and [LICENSE](LICENSE) files for more
+information.

RELEASE.md

@@ -1,45 +1,35 @@
 # 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. If a new `vMAJOR.MINOR`, replace "master" with "vVERSION" in the "Deprecations" page and commit
 
-5. Commit changes above with title "Release vVERSION" and generate a new tag
+5. If a new `vMAJOR.MINOR`, create a new branch "vMAJOR.MINOR" and set `CANONICAL=` in Makefile
 
-6. Run `make clean test` to ensure all tests pass from scratch and the CI is green
+6. Commit changes above with title "Release vVERSION" and generate new tag
 
-7. Recompile an existing project (for example, Ecto) to ensure manifests can be upgraded
+7. Run `make clean test` to ensure all tests pass from scratch and the CI is green
 
-8. Push branch and the new tag
+8. Recompile an existing project (for example, Ecto) to ensure manifests can be upgraded
 
-9. Publish new zips with `make zips`, upload `Precompiled.zip` and `Docs.zip` to GitHub Releases, and include SHAs+CHANGELOG
+9. Push branch and the new tag
 
-10. Add the release to `elixir.csv` (all releases) and `_data/elixir-versions.yml` (except for RCs) files in `elixir-lang/elixir-lang.github.com`
+10. Publish new zips with `make zips`, upload `Precompiled.zip` and `Docs.zip` to GitHub Releases
 
-11. Send an e-mail to elixir-lang-ann@googlegroups.com with title "Elixir vVERSION released". The body should be a link to the Release page on GitHub and the checksums. If it is a security release, prefix the title with the `[security]` tag
+11. Add the release to `elixir.csv` and `_data/elixir-versions.yml` files in `elixir-lang/elixir-lang.github.com`
 
-## Creating a new vMAJOR.MINOR branch
+12. After a new `vMAJOR.MINOR`, move back to master, bump versions, start new CHANGELOG, add `-dev` back and commit "Start vMAJOR.MINOR+1"
 
-### In the new branch
+## Places where version is mentioned
 
-1. Set `CANONICAL=` in /Makefile
-
-2. Update tables in "Compatibility and Deprecations"
-
-3. Commit "Prepare vMAJOR.MINOR for release"
-
-### Back in master
-
-1. Bump /VERSION file
-
-2. Start new /CHANGELOG.md
-
-3. Update tables in "Compatibility and Deprecations"
-
-4. Commit "Start vMAJOR.MINOR+1"
+* VERSION
+* CHANGELOG.md
+* src/elixir.app.src (not lib/elixir/src/elixir.app.src)

VERSION

@@ -1 +1 @@
-1.8.2
+1.5.3

bin/elixir

@@ -117,7 +117,11 @@ 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 $ERL -extra "$@"

bin/elixir.bat

@@ -50,7 +50,7 @@ set originPath=%~dp0
 rem Optional parameters before the "-extra" parameter
 set beforeExtra=
 
-rem Option which determines whether or not to use werl vs erl
+rem Flag which determines whether or not to use werl vs erl
 set useWerl=0
 
 rem Designates which mode / Elixir component to run as
@@ -88,7 +88,7 @@ if """"=="%par:--sname=%"               (set parsErlang=%parsErlang% -sname %1 &
 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:--erl=%"                 (set beforeExtra=%beforeExtra% %~1 && shift)
 goto:startloop
 
 rem ******* assume all pre-params are parsed ********************

lib/eex/lib/eex.ex

@@ -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
@@ -84,7 +83,7 @@ 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:
@@ -113,13 +112,13 @@ 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)
+      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
@@ -150,15 +149,15 @@ 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)
+      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
@@ -167,7 +166,7 @@ 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()
+  @spec compile_string(String.t, keyword) :: Macro.t | no_return
   def compile_string(source, options \\ []) when is_binary(source) and is_list(options) do
     EEx.Compiler.compile(source, options)
   end
@@ -176,9 +175,9 @@ 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()
+  @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)
+    options = Keyword.merge options, [file: filename, line: 1]
     compile_string(File.read!(filename), options)
   end
 
@@ -187,11 +186,11 @@ 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
+  @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
     compiled = compile_string(source, options)
@@ -210,10 +209,10 @@ defmodule EEx do
       EEx.eval_file "sample.eex", [bar: "baz"] #=> "foo baz"
 
   """
-  @spec eval_file(String.t(), keyword, keyword) :: any
+  @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)
+    options  = Keyword.put options, :file, filename
     compiled = compile_file(filename, options)
     do_eval(compiled, bindings, options)
   end

lib/eex/lib/eex/compiler.ex

@@ -9,25 +9,17 @@ 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()
+  @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
-
     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
-        }
-
+        state = %{engine: opts[:engine] || @default_engine,
+                  file: file, line: line, quoted: [], start_line: nil}
         init = state.engine.init(opts)
         generate_buffer(tokens, init, [], state)
-
       {:error, line, message} ->
         raise EEx.SyntaxError, line: line, file: file, message: message
     end
@@ -42,78 +34,53 @@ defmodule EEx.Compiler do
   end
 
   defp generate_buffer([{:expr, line, mark, chars} | rest], buffer, scope, state) do
-    expr = Code.string_to_quoted!(chars, line: line, file: state.file)
+    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)
   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
-      })
-
+      generate_buffer(rest, state.engine.handle_begin(buffer), [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)
   end
 
   defp generate_buffer([{:middle_expr, line, '', chars} | rest], 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(rest, state.engine.handle_begin(buffer), [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)
+  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
     {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}
   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)
+    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
+    raise EEx.SyntaxError, message: "unexpected end of expression <%#{chars}%>",
+                           file: state.file, line: line
   end
 
   defp generate_buffer([], buffer, [], state) do
@@ -121,10 +88,8 @@ 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
@@ -133,30 +98,22 @@ defmodule EEx.Compiler 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}
+    {current ++ placeholder ++ new_lines ++ chars,
+     %{state | quoted: [{key, state.engine.handle_end(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} | rest] = tokens, start, contents) do
     if only_spaces?(text) do
       {contents ++ text ++ chars, line, rest}
     else
       {contents, start, tokens}
     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}
   end
@@ -168,7 +125,7 @@ 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 +138,7 @@ 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

lib/eex/lib/eex/engine.ex

@@ -2,71 +2,46 @@ defmodule EEx.Engine do
   @moduledoc ~S"""
   Basic EEx engine that ships with Elixir.
 
-  An engine needs to implement all callbacks below.
+  An engine needs to implement six functions:
 
-  An engine may also `use EEx.Engine` to get the default behaviour
-  but this is not advised. In such cases, if any of the callbacks
-  are overridden, they must call `super()` to delegate to the
-  underlying `EEx.Engine`.
+    * `init(opts)` - called at the beginning of every text
+      and it must return the initial state.
+
+    * `handle_body(state)` - receives the state of the document
+      and it must return a quoted expression.
+
+    * `handle_text(state, text)` - it receives the state,
+      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
+
+      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: `""` and `"="`.
+
+      Read `handle_expr/3` below for more information about the markers
+      implemented by default by this engine.
+
+  `EEx.Engine` can be used directly if one desires to use the
+  default implementations for the functions above.
   """
 
   @type state :: term
 
-  @doc """
-  Called at the beginning of every template.
-
-  It must return the initial state.
-  """
   @callback init(opts :: keyword) :: state
-
-  @doc """
-  Called at the end of every template.
-
-  It must return Elixir's quoted expressions for the template.
-  """
-  @callback handle_body(state) :: Macro.t()
-
-  @doc """
-  Called for the text/static parts of a template.
-
-  It must return the updated state.
-  """
-  @callback handle_text(state, text :: String.t()) :: state
-
-  @doc """
-  Called for the dynamic/code parts of a template.
-
-  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 an
-  appropriate implementation raises `EEx.SyntaxError`.
-
-  It must return the updated state.
-  """
-  @callback handle_expr(state, marker :: String.t(), expr :: Macro.t()) :: state
-
-  @doc """
-  Invoked at the beginning of every nesting.
-
-  It must return a new state that is used only inside the nesting.
-  Once the nesting terminates, the current `state` is resumed.
-  """
+  @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
-
-  @doc """
-  Invokes at the end of a nesting.
-
-  It must return Elixir's quoted expressions for the nesting.
-  """
-  @callback handle_end(state) :: Macro.t()
+  @callback handle_end(state) :: Macro.t
 
   @doc false
   defmacro __using__(_) do
@@ -77,24 +52,24 @@ defmodule EEx.Engine do
         EEx.Engine.init(opts)
       end
 
-      def handle_body(state) do
-        EEx.Engine.handle_body(state)
+      def handle_body(quoted) do
+        EEx.Engine.handle_body(quoted)
       end
 
-      def handle_begin(state) do
-        EEx.Engine.handle_begin(state)
+      def handle_begin(quoted) do
+        EEx.Engine.handle_begin(quoted)
       end
 
-      def handle_end(state) do
-        EEx.Engine.handle_end(state)
+      def handle_end(quoted) do
+        EEx.Engine.handle_end(quoted)
       end
 
-      def handle_text(state, text) do
-        EEx.Engine.handle_text(state, text)
+      def handle_text(buffer, text) do
+        EEx.Engine.handle_text(buffer, text)
       end
 
-      def handle_expr(state, marker, expr) do
-        EEx.Engine.handle_expr(state, marker, expr)
+      def handle_expr(buffer, marker, expr) do
+        EEx.Engine.handle_expr(buffer, marker, expr)
       end
 
       defoverridable EEx.Engine
@@ -110,110 +85,92 @@ defmodule EEx.Engine do
   This can be added to any custom engine by invoking
   `handle_assign/1` with `Macro.prewalk/2`:
 
-      def handle_expr(state, token, expr) do
+      def handle_expr(buffer, token, expr) do
         expr = Macro.prewalk(expr, &EEx.Engine.handle_assign/1)
-        super(state, token, expr)
+        EEx.Engine.handle_expr(buffer, token, expr)
       end
 
   """
-  @spec handle_assign(Macro.t()) :: Macro.t()
+  @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
+  @spec fetch_assign!(Access.t, Access.key) :: term | nil
   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.warn "assign @#{key} not available in EEx template. " <>
+                "Please ensure all assigns are given as options. " <>
+                "Available assigns: #{inspect keys}"
         nil
     end
   end
 
-  @doc false
+  @doc """
+  Returns an empty string as initial buffer.
+  """
   def init(_opts) do
-    %{
-      binary: [],
-      dynamic: [],
-      vars_count: 0
-    }
+    ""
   end
 
-  @doc false
-  def handle_begin(state) do
-    check_state!(state)
-    %{state | binary: [], dynamic: []}
+  @doc """
+  Returns an empty string as the new buffer.
+  """
+  def handle_begin(_previous) do
+    ""
   end
 
-  @doc false
+  @doc """
+  End of the new buffer.
+  """
   def handle_end(quoted) do
-    handle_body(quoted)
+    quoted
   end
 
-  @doc false
-  def handle_body(state) do
-    check_state!(state)
-    %{binary: binary, dynamic: dynamic} = state
-    binary = {:<<>>, [], Enum.reverse(binary)}
-    dynamic = [binary | dynamic]
-    {:__block__, [], Enum.reverse(dynamic)}
+  @doc """
+  The default implementation simply returns the given expression.
+  """
+  def handle_body(quoted) do
+    quoted
   end
 
-  @doc false
-  def handle_text(state, text) do
-    %{binary: binary} = state
-    %{state | binary: [text | binary]}
+  @doc """
+  The default implementation simply concatenates text to the buffer.
+  """
+  def handle_text(buffer, text) do
+    quote do: unquote(buffer) <> unquote(text)
   end
 
-  @doc false
-  def handle_expr(state, "=", ast) do
-    %{binary: binary, dynamic: dynamic, vars_count: vars_count} = state
-    var = Macro.var(:"arg#{vars_count}", __MODULE__)
+  @doc """
+  Implements expressions according to the markers.
 
-    ast =
-      quote do
-        unquote(var) = String.Chars.to_string(unquote(ast))
-      end
+      <% Elixir expression - inline with output %>
+      <%= Elixir expression - replace with result %>
 
-    segment =
-      quote do
-        unquote(var) :: binary
-      end
-
-    %{state | dynamic: [ast | dynamic], binary: [segment | binary], vars_count: vars_count + 1}
+  All other markers are not implemented by this engine.
+  """
+  def handle_expr(buffer, "=", expr) do
+    quote do
+      tmp1 = unquote(buffer)
+      tmp1 <> String.Chars.to_string(unquote(expr))
+    end
   end
 
-  def handle_expr(state, "", ast) do
-    %{dynamic: dynamic} = state
-    %{state | dynamic: [ast | dynamic]}
-  end
-
-  def handle_expr(_state, marker, _ast) when marker in ["/", "|"] do
-    raise EEx.SyntaxError,
-          "unsupported EEx syntax <%#{marker} %> (the syntax is valid but not supported by the current EEx engine)"
-  end
-
-  defp check_state!(%{binary: _, dynamic: _, vars_count: _}), do: :ok
-
-  defp check_state!(state) do
-    raise "unexpected EEx.Engine state: #{inspect(state)}. " <>
-            "This typically means a bug or an outdated EEx.Engine or tool"
+  def handle_expr(buffer, "", expr) do
+    quote do
+      tmp2 = unquote(buffer)
+      unquote(expr)
+      tmp2
+    end
   end
 end

lib/eex/lib/eex/tokenizer.ex

@@ -1,12 +1,10 @@
 defmodule EEx.Tokenizer do
   @moduledoc false
 
-  @type content :: IO.chardata()
+  @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}
+  @type token :: {:text, content} |
+                 {:expr | :start_expr | :middle_expr | :end_expr, line, '=' | '', content}
 
   @doc """
   Tokenizes the given charlist or binary.
@@ -21,7 +19,7 @@ defmodule EEx.Tokenizer do
 
   Or `{:error, line, error}` in case of errors.
   """
-  @spec tokenize(binary | charlist, line, keyword) :: {:ok, [token]} | {:error, line, String.t()}
+  @spec tokenize(binary | charlist, line, keyword) :: {:ok, [token]} | {:error, line, String.t}
   def tokenize(bin, line, opts \\ [])
 
   def tokenize(bin, line, opts)
@@ -35,17 +33,15 @@ defmodule EEx.Tokenizer do
   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 +49,22 @@ 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)
+    tokenize t, line, opts, [h | buffer], acc
   end
 
   defp tokenize([], _line, _opts, buffer, acc) do
@@ -79,8 +73,8 @@ 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
@@ -94,11 +88,11 @@ defmodule EEx.Tokenizer do
   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])
+    expr t, line, [h | buffer]
   end
 
   defp expr([], line, _buffer) do
@@ -129,8 +123,8 @@ 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 +132,27 @@ 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
@@ -190,12 +183,10 @@ defmodule EEx.Tokenizer do
   # 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

lib/eex/mix.exs

@@ -1,10 +1,10 @@
-defmodule EEx.MixProject do
+defmodule EEx.Mixfile do
   use Mix.Project
 
   def project do
     [
       app: :eex,
-      version: System.version(),
+      version: System.version,
       build_per_environment: false
     ]
   end

lib/eex/test/eex/smart_engine_test.exs

@@ -1,41 +1,37 @@
-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
 
   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})
+    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)
-
+    stderr = ExUnit.CaptureIO.capture_io(:stderr, fn ->
+      assert_eval "", "<%= @foo %>", assigns: %{}
+    end)
     assert stderr =~ "assign @foo not available in EEx template"
   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
     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)

lib/eex/test/eex/tokenizer_test.exs

@@ -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

lib/eex/test/eex_test.exs

@@ -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
@@ -52,7 +55,7 @@ defmodule EExTest do
 
   describe "evaluates" do
     test "simple string" do
-      assert_eval("foo bar", "foo bar")
+      assert_eval "foo bar", "foo bar"
     end
 
     test "Unicode" do
@@ -60,14 +63,13 @@ defmodule EExTest do
         • <%= "•" %> •
         <%= "Jößé Vâlìm" %> Jößé Vâlìm
       """
-
-      assert_eval("  • • •\n  Jößé Vâlìm Jößé Vâlìm\n", template)
+      assert_eval "  • • •\n  Jößé Vâlìm Jößé Vâlìm\n", template
     end
 
     test "trim mode" do
       string = "<%= 123 %> \n456\n  <%= 789 %>"
       expected = "123456\n789"
-      assert_eval(expected, string, [], trim: true)
+      assert_eval expected, string, [], trim: true
     end
 
     test "trim mode with middle expression" do
@@ -79,141 +81,103 @@ defmodule EExTest do
         that
       <% end %>
       """
-
       expected = "  that\n"
-      assert_eval(expected, string, [], trim: true)
+      assert_eval expected, string, [], trim: true
     end
 
     test "embedded code" do
-      assert_eval("foo bar", "foo <%= :bar %>")
+      assert_eval "foo bar", "foo <%= :bar %>"
     end
 
     test "embedded code with binding" do
-      assert EEx.eval_string("foo <%= bar %>", bar: 1) == "foo 1"
+      assert EEx.eval_string("foo <%= bar %>", [bar: 1]) == "foo 1"
     end
 
     test "embedded code with do end when true" do
-      assert_eval("foo bar", "foo <%= if true do %>bar<% end %>")
+      assert_eval "foo bar", "foo <%= if true do %>bar<% end %>"
     end
 
     test "embedded code with do end when false" do
-      assert_eval("foo ", "foo <%= if false do %>bar<% end %>")
+      assert_eval "foo ", "foo <%= if false do %>bar<% end %>"
     end
 
     test "embedded code with do end and expression" do
-      assert_eval("foo bar", "foo <%= if true do %><%= :bar %><% end %>")
+      assert_eval "foo bar", "foo <%= if true do %><%= :bar %><% 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 %>"
-      )
-
+      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 middle expression" do
-      assert_eval("foo bar", "foo <%= if true do %>bar<% else %>baz<% end %>")
+      assert_eval "foo bar", "foo <%= if true do %>bar<% else %>baz<% end %>"
     end
 
     test "embedded code with evaluated middle expression" do
-      assert_eval("foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>")
+      assert_eval "foo baz", "foo <%= if false do %>bar<% else %>baz<% end %>"
     end
 
     test "embedded code with nested do end" do
-      assert_eval("foo bar", "foo <%= if true do %><%= if true do %>bar<% end %><% end %>")
+      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 %>"
-      )
+      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) ) %>"
-      )
+      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 %>")
+      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], \",\" %>")
+      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 %>")
+      assert_eval "foo bar %>", "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 %>")
+        EEx.compile_string "foo <%= bar"
       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 %>")
+      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 %>")
+      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
 
     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 %>")
+        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 %>\"]
+        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
+        EEx.compile_string "foo <%= if true do %>true<% else %>false<%= end %>"
+      end) =~ ~s[unexpected beginning of EEx tag \"<%=\" on end of expression \"<%= end %>\"]
     end
   end
 
@@ -229,7 +193,7 @@ defmodule EExTest do
       <%= __ENV__.line %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "respects line numbers inside nested expressions" do
@@ -249,7 +213,7 @@ defmodule EExTest do
       <%= __ENV__.line %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "respects line numbers inside start expression" do
@@ -269,7 +233,7 @@ defmodule EExTest do
       <%= __ENV__.line %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "respects line numbers inside middle expression with ->" do
@@ -291,7 +255,7 @@ defmodule EExTest do
       <%= __ENV__.line %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "respects line number inside middle expressions with keywords" do
@@ -313,11 +277,11 @@ defmodule EExTest do
       <%= __ENV__.line %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "respects files" do
-      assert_eval("sample.ex", "<%= __ENV__.file %>", [], file: "sample.ex")
+      assert_eval "sample.ex", "<%= __ENV__.file %>", [], file: "sample.ex"
     end
   end
 
@@ -339,7 +303,7 @@ defmodule EExTest do
       <% end %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "inside cond" do
@@ -359,7 +323,7 @@ defmodule EExTest do
       <% end %>
       """
 
-      assert_eval(expected, string)
+      assert_eval expected, string
     end
 
     test "inside cond with do end" do
@@ -374,7 +338,7 @@ defmodule EExTest do
       <% end %>
       """
 
-      assert_eval("\n\n  Good\n \n", string)
+      assert_eval "\n\n  Good\n \n", string
     end
   end
 
@@ -388,7 +352,7 @@ defmodule EExTest do
       <%= 789 %>
       """
 
-      assert_eval("123\n\n789\n", string)
+      assert_eval "123\n\n789\n", string
     end
 
     test "inside comprehensions" do
@@ -397,8 +361,7 @@ defmodule EExTest do
       <% end %>
       <%= all || :done %>
       """
-
-      assert_eval("\ndone\n", string, packages: nil, all: nil)
+      assert_eval "\ndone\n", string, packages: nil, all: nil
     end
   end
 
@@ -406,19 +369,17 @@ defmodule EExTest 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)
+      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)
+      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 ->
+      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
@@ -426,31 +387,48 @@ defmodule EExTest do
 
     test "sets external resource attribute" do
       assert EExTest.Compiled.__info__(:attributes)[:external_resource] ==
-               [Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")]
+             [Path.join(__DIR__, "fixtures/eex_template_with_bindings.eex")]
     end
   end
 
   describe "precompiled" do
+
     test "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))
+      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 "from file does not affect backtrace" do
-      file = to_charlist(Path.relative_to_cwd(__ENV__.file))
+      assert EExTest.Compiled.before_compile ==
+        {8,
+          {EExTest.Compiled,
+            :before_compile,
+            0,
+            [file: to_charlist(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_charlist(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]}}
+      assert EExTest.Compiled.unknown ==
+        {29,
+          {EExTest.Compiled,
+            :unknown,
+            0,
+            [file: 'unknown', line: 28]
+         }
+       }
     end
   end
 
@@ -477,49 +455,24 @@ defmodule EExTest 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)})"
     end
-
-    def handle_expr(buffer, mark, expr) do
-      EEx.Engine.handle_expr(buffer, mark, expr)
-    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)
+      assert_eval "BODY(INIT:TEXT(foo))", "foo", [], 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
+      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
   end
 
   defp assert_eval(expected, actual, binding \\ [], opts \\ []) do
-    opts = Keyword.merge([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

lib/eex/test/test_helper.exs

@@ -1 +1 @@
-ExUnit.start(trace: "--trace" in System.argv())
+ExUnit.start [trace: "--trace" in System.argv]

lib/elixir/docs.exs

@@ -1,99 +0,0 @@
-# Returns config for Elixir docs
-[
-  extras: Path.wildcard("lib/elixir/pages/*.md"),
-  groups_for_functions: [
-    Guards: & &1[:guard] == true
-  ],
-  skip_undefined_reference_warnings_on: ["compatibility-and-deprecations"],
-  groups_for_modules: [
-    # [Kernel, Kernel.SpecialForms],
-
-    "Basic Types": [
-      Atom,
-      Base,
-      Bitwise,
-      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
-    ],
-    "Calendar": [
-      Calendar,
-      Calendar.ISO,
-      Calendar.TimeZoneDatabase,
-      Calendar.UTCOnlyTimeZoneDatabase
-    ],
-    "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
-    ]
-  ]
-]

lib/elixir/generate_app.escript

@@ -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]).

lib/elixir/lib/access.ex

@@ -1,53 +1,27 @@
 defmodule Access do
   @moduledoc """
-  Key-based access to data structures.
+  Key-based access to data structures using the `data[key]` 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.
+  Besides the cases above, this module provides convenience
+  functions for accessing other structures, like `at/1` for
+  lists and `elem/1` for tuples. Those functions can be used
+  by the nested update functions in `Kernel`, such as
+  `Kernel.get_in/2`, `Kernel.put_in/3`, `Kernel.update_in/3`,
+  `Kernel.get_and_update_in/3` and friends.
 
-  ## Key-value constructs
+  ## Dynamic lookups
 
-  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]
@@ -57,95 +31,110 @@ defmodule Access do
       iex> star_ratings[1.5]
       "★☆"
 
+  Note that the dynamic lookup syntax (`term[key]`) roughly translates to
+  `Access.get(term, key, nil)`.
+
+  `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 for key-value
+  data structures. The implementation should be added to the
+  module that defines the struct being accessed. `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.
+  ## Static lookups
 
-  ### Dot-based syntax
+  The `Access` syntax (`data[key]`) cannot be used to access fields in
+  structs, since structs do not implement the `Access` behaviour by
+  default. It is also a design decision: the dynamic access lookup
+  is meant to be used for dynamic key-value structures, like maps
+  and keywords, and not by static ones like structs (where fields are
+  known and not dynamic).
 
-  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.
-
-  Imagine a struct named `User` with a `:name` field. The following would raise:
+  Therefore Elixir provides a static lookup for struct fields and for atom
+  fields in maps. Imagine a struct named `User` with a `:name` field.
+  The following would raise:
 
       user = %User{name: "John"}
       user[:name]
       # ** (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 to access fields:
 
       user.name
       #=> "John"
 
+  The same `user.name` syntax can also be used by `Kernel.put_in/2`
+  for updating structs fields:
+
+      put_in user.name, "Mary"
+      #=> %User{name: "Mary"}
+
   Differently from `user[:name]`, `user.name` is not extensible via
   a behaviour and is restricted only to structs and atom keys in maps.
 
-  ### Summing up
+  As mentioned above, this works for atom keys in maps as well. Refer to the
+  `Map` module for more information on this.
 
-  The bracket-based syntax, `user[:name]`, is used by dynamic structures,
-  is extensible and returns nil on missing keys.
+  Summing up:
 
-  The dot-based syntax, `user.name`, is used exclusively to access atom
-  keys in maps and structs, and it raises on missing keys.
+    * `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
 
-  ## Nested data structures
+  ## Accessors
 
-  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`.
+  While Elixir provides built-in syntax only for traversing dynamic
+  and static key-value structures, this module provides convenience
+  functions for traversing other structures, like tuples and lists,
+  to be used alongside `Kernel.put_in/2` in others.
 
-  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:
+  For instance, given a user map with `: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}
+      ...>   %{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}
-        ]
-      }
+      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.
+
+  ## Implementing the Access behaviour for custom data structures
+
+  In order to be able to use the `Access` behaviour with custom data structures
+  (which have to be structs), such structures have to implement the `Access`
+  behaviour. For example, for a `User` struct, this would have to be done:
+
+      defmodule User do
+        defstruct [:name, :email]
+
+        @behaviour Access
+        # Implementation of the Access callbacks...
+      end
+
   """
 
   @type container :: keyword | struct | map
@@ -156,15 +145,15 @@ defmodule Access do
   @type value :: any
 
   @type get_fun(data, get_value) ::
-          (:get, data, (term -> term) ->
-             {get_value, new_data :: container})
+        (:get, data, (term -> term) ->
+        {get_value, new_data :: container})
 
   @type get_and_update_fun(data, get_value) ::
-          (:get_and_update, data, (term -> term) ->
-             {get_value, new_data :: container} | :pop)
+        (: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)
+        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`.
@@ -185,6 +174,28 @@ defmodule Access do
   """
   @callback fetch(term :: t, key) :: {:ok, value} | :error
 
+  @doc """
+  Invoked in order to access the value stored under `key` in the given term `term`,
+  defaulting to `default` if not present.
+
+  This function should return the value under `key` in `term` if there's
+  such key, otherwise `default`.
+
+  For most data structures, this can be implemented using `fetch/2` internally;
+  for example:
+
+      def get(structure, key, default) do
+        case fetch(structure, key) do
+          {:ok, value} -> value
+          :error       -> default
+        end
+      end
+
+  See the `Map.get/3` and `Keyword.get/3` implementations for examples of
+  how to implement this callback.
+  """
+  @callback get(term :: t, key, default :: value) :: value
+
   @doc """
   Invoked in order to access the value under `key` and update it at the same time.
 
@@ -194,12 +205,9 @@ defmodule Access do
 
   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`.
+  - `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`
@@ -208,8 +216,8 @@ defmodule Access do
   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
+  @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.
@@ -225,19 +233,17 @@ defmodule Access do
   """
   @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
+      stacktrace = System.stacktrace
+      e =
+        case stacktrace do
           [unquote(top) | _] ->
-            reason = "#{inspect(unquote(module))} does not implement the Access behaviour"
-            %{unquote(exception) | reason: reason}
-
+            %{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
 
@@ -247,25 +253,16 @@ defmodule Access do
 
   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
-
   """
   @spec fetch(container, term) :: {:ok, term} | :error
   @spec fetch(nil_container, any) :: :error
   def fetch(container, key)
 
-  def fetch(%module{} = container, key) do
-    module.fetch(container, key)
+  def fetch(%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
@@ -284,7 +281,7 @@ defmodule Access do
 
   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
@@ -297,32 +294,17 @@ defmodule Access do
 
   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
-
   """
   @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
+  def get(%{__struct__: struct} = container, key, default) do
     try do
-      module.fetch(container, key)
+      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], _}
     else
       {:ok, value} -> value
       :error -> default
@@ -345,7 +327,7 @@ defmodule Access do
 
   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)
+      "the Access calls for keywords expect the key to be an atom, got: " <> inspect(key)
   end
 
   def get(nil, _key, default) do
@@ -366,19 +348,15 @@ defmodule Access do
   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`.
   """
-  @spec get_and_update(data, key, (value -> {get_value, value} | :pop)) :: {get_value, data}
-        when get_value: var, data: container
+  @spec get_and_update(data, key, (value -> {get_value, value} | :pop)) ::
+        {get_value, data} when get_value: var, data: container
   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
@@ -390,7 +368,8 @@ 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"
+    raise ArgumentError,
+      "could not put/update key #{inspect key} on a nil value"
   end
 
   @doc """
@@ -420,11 +399,11 @@ defmodule Access do
 
   """
   @spec pop(data, key) :: {value, data} when data: container
-  def pop(%module{} = container, key) do
-    module.pop(container, key)
+  def pop(%{__struct__: struct} = container, key) do
+    struct.pop(container, key)
   rescue
-    exception in UndefinedFunctionError ->
-      raise_undefined_behaviour(exception, module, {^module, :pop, [^container, ^key], _})
+    e in UndefinedFunctionError ->
+      raise_undefined_behaviour e, struct, {^struct, :pop, [^container, ^key], _}
   end
 
   def pop(map, key) when is_map(map) do
@@ -436,7 +415,8 @@ defmodule Access do
   end
 
   def pop(nil, key) do
-    raise ArgumentError, "could not pop key #{inspect(key)} on a nil value"
+    raise ArgumentError,
+      "could not pop key #{inspect key} on a nil value"
   end
 
   ## Accessors
@@ -450,8 +430,8 @@ defmodule Access do
   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"
+      iex> get_in(%{}, [Access.key(:user, %{}), Access.key(:name)])
+      nil
 
   Such is also useful when using update functions, allowing us to introduce
   values as we traverse the data structure for updates:
@@ -464,8 +444,8 @@ defmodule Access do
       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)}
+      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)])
@@ -485,10 +465,8 @@ defmodule Access 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)}
@@ -502,15 +480,15 @@ defmodule Access do
   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.
+  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)}
+      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)])
@@ -529,17 +507,14 @@ defmodule Access 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)}"
+        raise "Access.key!/1 expected a map/struct, got: #{inspect data}"
     end
   end
 
@@ -551,16 +526,13 @@ defmodule Access do
 
   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)}
+      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)])
@@ -573,23 +545,20 @@ defmodule Access do
 
   """
   @spec elem(non_neg_integer) :: access_fun(data :: tuple, get_value :: term)
-  def elem(index) when is_integer(index) and index >= 0 do
+  def elem(index) when is_integer(index) 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)}"
+        raise "Access.elem/1 expected a tuple, got: #{inspect data}"
     end
   end
 
@@ -604,8 +573,8 @@ defmodule Access do
       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)}
+      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])
@@ -615,8 +584,8 @@ defmodule Access do
   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}
+      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]}
 
@@ -640,7 +609,7 @@ defmodule Access do
   end
 
   defp all(_op, data, _next) do
-    raise "Access.all/0 expected a list, got: #{inspect(data)}"
+    raise "Access.all/0 expected a list, got: #{inspect data}"
   end
 
   defp all([head | rest], next, gets, updates) do
@@ -665,8 +634,8 @@ defmodule Access do
       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)}
+      iex> get_and_update_in(list, [Access.at(0), :name], fn
+      ...>   prev -> {prev, String.upcase(prev)}
       ...> end)
       {"john", [%{name: "JOHN"}, %{name: "mary"}]}
 
@@ -684,8 +653,8 @@ defmodule Access do
       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)}
+      iex> get_and_update_in(list, [Access.at(10), :name], fn
+      ...>   prev -> {prev, String.upcase(prev)}
       ...> end)
       {nil, [%{name: "john"}, %{name: "mary"}]}
 
@@ -702,7 +671,7 @@ defmodule Access do
   """
   @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
+    fn(op, data, next) -> at(op, data, index, next) end
   end
 
   defp at(:get, data, index, next) when is_list(data) do
@@ -714,7 +683,7 @@ defmodule Access do
   end
 
   defp at(_op, data, _index, _next) do
-    raise "Access.at/1 expected a list, got: #{inspect(data)}"
+    raise "Access.at/1 expected a list, got: #{inspect data}"
   end
 
   defp get_and_update_at([head | rest], 0, next, updates) do
@@ -731,86 +700,4 @@ defmodule Access do
   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)}
-  end
 end

lib/elixir/lib/agent.ex

@@ -11,42 +11,44 @@ defmodule Agent do
 
   ## Examples
 
-  For example, the following agent implements a counter:
+  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:
 
-      defmodule Counter do
+      defmodule Mix.TasksServer do
         use Agent
 
-        def start_link(initial_value) do
-          Agent.start_link(fn -> initial_value end, name: __MODULE__)
+        def start_link do
+          Agent.start_link(fn -> MapSet.new end, name: __MODULE__)
         end
 
-        def value do
-          Agent.get(__MODULE__, & &1)
+        @doc "Checks if the task has already executed"
+        def executed?(task, project) do
+          item = {task, project}
+          Agent.get(__MODULE__, fn set ->
+            item in set
+          end)
         end
 
-        def increment do
-          Agent.update(__MODULE__, &(&1 + 1))
+        @doc "Marks a task as executed"
+        def put_task(task, project) do
+          item = {task, project}
+          Agent.update(__MODULE__, &MapSet.put(&1, item))
+        end
+
+        @doc "Resets the executed tasks and returns the previous list of tasks"
+        def take_all() do
+          Agent.get_and_update(__MODULE__, fn set ->
+            {Enum.into(set, []), MapSet.new}
+          end)
         end
       end
 
-  Usage would be:
-
-      Counter.start_link(0)
-
-      Counter.value     #=> 0
-      Counter.increment #=> :ok
-      Counter.increment #=> :ok
-      Counter.value     #=> 2
-
-  Thanks to the agent server process, the counter can be safely incremented
-  concurrently.
-
-  Agents provide a segregation between the client and server APIs (similar to
-  `GenServer`s). In particular, the functions passed as arguments to the calls to
-  `Agent` functions are invoked 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.
+  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.
 
   Consider these two examples:
 
@@ -57,7 +59,7 @@ defmodule Agent do
 
       # Compute in the agent/client
       def get_something(agent) do
-        Agent.get(agent, & &1) |> do_something_expensive()
+        Agent.get(agent, &(&1)) |> do_something_expensive()
       end
 
   The first function blocks the agent. The second function copies all the state
@@ -71,61 +73,20 @@ defmodule Agent do
   than in the server can lead to race conditions if multiple clients are trying
   to update the same state to different values.
 
-  ## How to supervise
+  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:
 
-  An `Agent` is most commonly started under a supervision tree.
-  When we invoke `use Agent`, it automatically defines a `child_spec/1`
-  function that allows us to start the agent directly under a supervisor.
-  To start an agent under a supervisor with an initial counter of 0,
-  one may do:
-
-      children = [
-        {Counter, 0}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  While one could also simply pass the `Counter` as a child to the supervisor,
-  such as:
-
-      children = [
-        Counter # Same as {Counter, []}
-      ]
-
-      Supervisor.start_link(children, strategy: :one_for_all)
-
-  The definition above wouldn't work for this particular example,
-  as it would attempt to start the counter with an initial value
-  of an empty list. However, this may be a viable option in your
-  own agents. A common approach is to use a keyword list, as that
-  would allow setting the initial value and giving a name to the
-  counter process, for example:
-
-      def start_link(opts) do
-        {initial_value, opts} = Keyword.pop(opts, :initial_value, 0)
-        Agent.start_link(fn -> initial_value end, opts)
-      end
-
-  and then you can use `Counter`, `{Counter, name: :my_counter}` or
-  even `{Counter, initial_value: 0, name: :my_counter}` as a child
-  specification.
-
-  `use Agent` also accepts a list of options which configures the
-  child specification and therefore how it runs under a supervisor.
-  The generated `child_spec/1` can be customized with the following options:
-
-    * `:id` - the child specification identifier, defaults to the current module
+    * `:id` - the child specification id, defauts 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, either immediately or by giving it time to shut down
+    * `:shutdown` - how to shut down the child
 
   For example:
 
       use Agent, restart: :transient, shutdown: 10_000
 
-  See the "Child specification" section in the `Supervisor` module for more
-  detailed information. The `@doc` annotation immediately preceding
-  `use Agent` will be attached to the generated `child_spec/1` function.
+  See the `Supervisor` docs for more information.
 
   ## Name registration
 
@@ -178,12 +139,7 @@ defmodule Agent do
   @typedoc "The agent state"
   @type state :: term
 
-  @doc """
-  Returns a specification to start an agent under a supervisor.
-
-  See the "Child specification" section in the `Supervisor` module for more detailed information.
-  """
-  @doc since: "1.5.0"
+  @doc false
   def child_spec(arg) do
     %{
       id: Agent,
@@ -194,21 +150,17 @@ defmodule Agent do
   @doc false
   defmacro __using__(opts) do
     quote location: :keep, bind_quoted: [opts: opts] do
-      if Module.get_attribute(__MODULE__, :doc) == nil do
-        @doc """
-        Returns a specification to start this module under a supervisor.
-
-        See `Supervisor`.
-        """
-      end
+      spec = [
+        id: opts[:id] || __MODULE__,
+        start: Macro.escape(opts[:start]) || quote(do: {__MODULE__, :start_link, [arg]}),
+        restart: opts[:restart] || :permanent,
+        shutdown: opts[:shutdown] || 5000,
+        type: :worker
+      ]
 
+      @doc false
       def child_spec(arg) do
-        default = %{
-          id: __MODULE__,
-          start: {__MODULE__, :start_link, [arg]}
-        }
-
-        Supervisor.child_spec(default, unquote(Macro.escape(opts)))
+        %{unquote_splicing(spec)}
       end
 
       defoverridable child_spec: 1
@@ -220,9 +172,9 @@ defmodule Agent do
 
   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 in the server
-  process, and should return the initial agent state. Note that `start_link/2`
-  does not return until the given function has returned.
+  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
+  until the given function has returned.
 
   ## Options
 
@@ -259,7 +211,7 @@ defmodule Agent do
       %RuntimeError{message: "oops"}
 
   """
-  @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
@@ -271,7 +223,7 @@ defmodule Agent do
   instead of an anonymous function; `fun` in `module` will be called with the
   given arguments `args` to initialize the state.
   """
-  @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
@@ -284,11 +236,11 @@ defmodule Agent do
   ## Examples
 
       iex> {:ok, pid} = Agent.start(fn -> 42 end)
-      iex> Agent.get(pid, fn state -> state 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
@@ -298,7 +250,7 @@ defmodule Agent do
 
   See `start_link/4` for more information.
   """
-  @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

lib/elixir/lib/agent/server.ex

@@ -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
 

lib/elixir/lib/application.ex

@@ -2,152 +2,16 @@ 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*.
-
-  ## The application resource file
-
-  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'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.
-
-  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`.
-
-  ## 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`:
-
-      def application do
-        [env: [redis_host: "localhost"]]
-      end
-
-  and the generated application resource file is going to have it included.
-
-  The environment is available after loading the application, which is a process
-  explained later:
-
-      Application.load(:APP_NAME)
-      #=> :ok
-
-      Application.get_env(:APP_NAME, :redis_host)
-      #=> "localhost"
-
-  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.
-
-  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 overridden via the `-config` option of
-  `erl`, as well as command-line options, 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:
-
-      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:
-
-      defmodule MyApp do
-        use Application
-
-        def start(_type, _args) do
-          children = []
-          Supervisor.start_link(children, strategy: :one_for_one)
-        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.
-
-  The `type` argument passed to `c: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.
-
-  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.
-
-  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` options 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
+  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. In Elixir, the Mix build tool is responsible for compiling your
+  source code and generating your application `.app` file. You can learn more
+  about the generation of `.app` files by typing `mix help compile.app`.
 
   Once your application is compiled, running your system is a matter of starting
   your current application and its dependencies. Differently from other languages,
@@ -155,57 +19,17 @@ defmodule Application do
   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.
+  Starting an application is done via the "application module callback", which
+  is a module that defines the `start/2` function. The `start/2` function should
+  then start a supervisor, which is often called as the top-level supervisor, since
+  it sits at the root of a potentially long supervision tree. When the system is
+  shutting down, all applications shut down their top-level supervisor, which
+  terminates children in the opposite order they are started.
 
-  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.
-
-  By default, a SIGTERM from the operating system will automatically translate to
-  `System.stop/0`. You can also have 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
+  We have mentioned the Mix build tool is responsible for compiling applications,
+  but it is also capable of running applications. For example, `mix test`
+  automatically starts your application dependencies and your application itself
+  before your test runs. `mix run --no-halt` also 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)
@@ -220,14 +44,100 @@ defmodule Application do
   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
+  Shutting down a live system cleanly can be done by calling `System.stop/1`.
+  It will shut down all applications in the opposite order they are started.
+  Each application will then shutdown its top-level supervisor, if one is
+  available, which then shuts down its children.
 
-  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).
+  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.
+
+  Applications also provide an "application environment", which is how
+  applications are configured. The application environment can either be set
+  statically, via a configuration file, or dynamically via `put_env/3` and
+  friends.
+
+  Over the next sections, we will cover the "application environment" and
+  the "application module callback" in more detail.
+
+  ## Application environment
+
+  Once an application is started, OTP provides an application environment
+  that can be used to configure the application.
+
+  Assuming you are inside a Mix project, you can edit the `application/0`
+  function in the `mix.exs` file to the following:
+
+      def application do
+        [env: [hello: :world]]
+      end
+
+  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:
+
+      Application.get_env(:APP_NAME, :hello)
+      #=> :world
+
+  Applications and dependencies in Mix projects are typically configured
+  via the `config/config.exs` file. For example, someone using your
+  application can configure the `:hello` key as follows:
+
+      config :APP_NAME, hello: :brand_new_world
+
+  It is also possible to configure applications dynamically via `put_env/3`.
+
+  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).
+
+  ## Application module callback
+
+  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
+
+  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
+          MyApp.Supervisor.start_link()
+        end
+      end
+
+  `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 `start/2` is usually `:normal` unless in a
+  distributed setup where application takeovers and failovers are configured.
+  Distributed applications is beyond the scope of this documentation. For those
+  interested on the topic, please access the OTP documentation:
+
+    * [`:application` module](http://www.erlang.org/doc/man/application.html)
+    * [Applications – OTP Design Principles](http://www.erlang.org/doc/design_principles/applications.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.
+
+  An application without a supervision tree doesn't define an application
+  module callback in the application definition in `mix.exs` file. Even though
+  there is no module with application callbacks such as `start/2` and
+  `stop/1`, the application can be started and stopped the same way as an
+  application with a supervision tree.
   """
 
   @doc """
@@ -265,30 +175,20 @@ defmodule Application do
   callback.
   """
   @callback start(start_type, start_args :: term) ::
-              {:ok, pid}
-              | {:ok, pid, state}
-              | {:error, reason :: term}
+    {:ok, pid} |
+    {:ok, pid, state} |
+    {:error, reason :: term}
 
   @doc """
-  Called before stopping the application.
+  Called when an application is stopped.
 
-  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
+  This function is called when an application has stopped, i.e., when 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
+  `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.
+  `state` is the return value of the `start/2` callback or the return value of
+  the `prep_stop/1` function if the application module defines such a function.
 
   `use Application` defines a default implementation of this function which does
   nothing and just returns `:ok`.
@@ -296,7 +196,7 @@ defmodule Application do
   @callback stop(state) :: term
 
   @doc """
-  Starts an application in synchronous phases.
+  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
@@ -304,20 +204,10 @@ defmodule Application do
   in the order they are listed in.
   """
   @callback start_phase(phase :: term, start_type, phase_args :: term) ::
-              :ok | {:error, reason :: term}
+    :ok |
+    {:error, reason :: term}
 
-  @doc """
-  Callback invoked after code upgrade, if the application environment
-  has changed.
-
-  `changed` is a keyword list of keys and their changed values in the
-  application environment. `new` is a keyword list with all new keys
-  and their values. `removed` is a list with all removed keys.
-  """
-  @callback config_change(changed, new, removed) :: :ok
-            when changed: keyword, new: keyword, removed: [atom]
-
-  @optional_callbacks start_phase: 3, prep_stop: 1, config_change: 3
+  @optional_callbacks start_phase: 3
 
   @doc false
   defmacro __using__(_) do
@@ -337,38 +227,26 @@ defmodule Application do
   @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.
   """
   @spec spec(app) :: [{key, value}] | nil
-  def spec(app) when is_atom(app) 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
 
@@ -380,7 +258,7 @@ defmodule Application do
   will raise. Returns `nil` if the application is not loaded.
   """
   @spec spec(app, key) :: value | nil
-  def spec(app, key) when is_atom(app) and key in @application_keys do
+  def spec(app, key) when key in @application_keys do
     case :application.get_key(app, key) do
       {:ok, value} -> value
       :undefined -> nil
@@ -406,7 +284,7 @@ defmodule Application do
   Returns all key-value pairs for `app`.
   """
   @spec get_all_env(app) :: [{key, value}]
-  def get_all_env(app) when is_atom(app) do
+  def get_all_env(app) do
     :application.get_all_env(app)
   end
 
@@ -415,44 +293,9 @@ 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) when is_atom(app) do
+  def get_env(app, key, default \\ nil) do
     :application.get_env(app, key, default)
   end
 
@@ -462,7 +305,7 @@ defmodule Application do
   If the configuration parameter does not exist, the function returns `:error`.
   """
   @spec fetch_env(app, key) :: {:ok, value} | :error
-  def fetch_env(app, key) when is_atom(app) do
+  def fetch_env(app, key) do
     case :application.get_env(app, key) do
       {:ok, value} -> {:ok, value}
       :undefined -> :error
@@ -474,30 +317,14 @@ defmodule Application do
 
   If the configuration parameter does not exist, raises `ArgumentError`.
   """
-  @spec fetch_env!(app, key) :: value
-  def fetch_env!(app, key) when is_atom(app) 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
 
@@ -513,13 +340,13 @@ defmodule Application do
   environment values specified in the `.app` file will override the ones
   previously set.
 
-  The `:persistent` option can be set to `true` when there is a need to guarantee
+  The persistent option can be set to `true` when there is a need to guarantee
   parameters set with this function will not be overridden by the ones defined
   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
-  def put_env(app, key, value, opts \\ []) when is_atom(app) do
+  @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
 
@@ -528,8 +355,8 @@ defmodule Application do
 
   See `put_env/4` for a description of the options.
   """
-  @spec delete_env(app, key, timeout: timeout, persistent: boolean) :: :ok
-  def delete_env(app, key, opts \\ []) when is_atom(app) do
+  @spec delete_env(app, key, [timeout: timeout, persistent: boolean]) :: :ok
+  def delete_env(app, key, opts \\ []) do
     :application.unset_env(app, key, opts)
   end
 
@@ -543,7 +370,7 @@ 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
@@ -555,7 +382,7 @@ 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
@@ -594,7 +421,7 @@ 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
@@ -605,7 +432,7 @@ defmodule Application do
   When stopped, the application is still loaded.
   """
   @spec stop(app) :: :ok | {:error, term}
-  def stop(app) when is_atom(app) do
+  def stop(app) do
     :application.stop(app)
   end
 
@@ -658,48 +485,29 @@ defmodule Application do
   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).
   """
-  @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)
-
-  def app_dir(app, path) when is_atom(app) and is_binary(path) do
+  @spec app_dir(app, String.t | [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_atom(app) and is_list(path) do
+  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
@@ -707,9 +515,9 @@ 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 """
@@ -717,7 +525,7 @@ 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)
@@ -736,8 +544,8 @@ defmodule Application do
 
   # {: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)
+    Exception.format_mfa(mod, :start, args) <> " returned an error: " <>
+      Exception.format_exit(reason)
   end
 
   # error or exit(reason) call, use exit reason as reason.
@@ -747,7 +555,8 @@ defmodule Application do
 
   # 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)
+    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

lib/elixir/lib/atom.ex

@@ -16,7 +16,7 @@ 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
@@ -38,8 +38,8 @@ defmodule Atom do
   end
 
   # TODO: Remove by 2.0
+  # (hard-deprecated in elixir_dispatch)
   @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

lib/elixir/lib/base.ex

@@ -92,10 +92,10 @@ defmodule Base do
 
   """
 
-  b16_alphabet = '0123456789ABCDEF'
-  b64_alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
+  b16_alphabet    = '0123456789ABCDEF'
+  b64_alphabet    = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
   b64url_alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_'
-  b32_alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
+  b32_alphabet    = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'
   b32hex_alphabet = '0123456789ABCDEFGHIJKLMNOPQRSTUV'
 
   defmacrop encode_pair(alphabet, case, value) do
@@ -108,7 +108,6 @@ defmodule Base do
 
   defp encode_pair_clauses(alphabet, case) when case in [:sensitive, :upper] do
     shift = shift(alphabet)
-
     alphabet
     |> Enum.with_index()
     |> encode_clauses(shift)
@@ -116,9 +115,8 @@ defmodule Base do
 
   defp encode_pair_clauses(alphabet, :lower) do
     shift = shift(alphabet)
-
     alphabet
-    |> Stream.map(fn c -> if c in ?A..?Z, do: c - ?A + ?a, else: c end)
+    |> Stream.map(fn c -> (if c in ?A..?Z, do: c - ?A + ?a, else: c) end)
     |> Enum.with_index()
     |> encode_clauses(shift)
   end
@@ -131,11 +129,10 @@ defmodule Base do
   end
 
   defp encode_clauses(alphabet, shift) do
-    for {encoding1, value1} <- alphabet,
-        {encoding2, value2} <- alphabet do
+    for {encoding1, value1} <- alphabet, {encoding2, value2} <- alphabet do
       encoding = bsl(encoding1, 8) + encoding2
       value = bsl(value1, shift) + value2
-      [clause] = quote(do: (unquote(value) -> unquote(encoding)))
+      [clause] = quote do: (unquote(value) -> unquote(encoding))
       clause
     end
   end
@@ -153,7 +150,6 @@ defmodule Base do
       alphabet
       |> Enum.with_index()
       |> decode_clauses()
-
     clauses ++ bad_digit_clause()
   end
 
@@ -162,8 +158,8 @@ defmodule Base do
       alphabet
       |> Stream.with_index()
       |> Enum.split_with(fn {encoding, _} -> encoding in ?A..?Z end)
-
-    lowers = Enum.map(uppers, fn {encoding, value} -> {encoding - ?A + ?a, value} end)
+    lowers =
+      Enum.map(uppers, fn {encoding, value} -> {encoding - ?A + ?a, value} end)
 
     if length(uppers) > length(rest) do
       decode_mixed_clauses(lowers, rest)
@@ -174,35 +170,29 @@ defmodule Base do
 
   defp decode_char_clauses(alphabet, :mixed) when length(alphabet) == 16 do
     alphabet = Enum.with_index(alphabet)
-
     lowers =
       alphabet
       |> Stream.filter(fn {encoding, _} -> encoding in ?A..?Z end)
       |> Enum.map(fn {encoding, value} -> {encoding - ?A + ?a, value} end)
-
     decode_mixed_clauses(alphabet, lowers)
   end
 
   defp decode_char_clauses(alphabet, :mixed) when length(alphabet) == 32 do
-    clauses =
-      alphabet
-      |> Stream.with_index()
-      |> Enum.flat_map(fn {encoding, value} = pair ->
-        if encoding in ?A..?Z do
-          [pair, {encoding - ?A + ?a, value}]
-        else
-          [pair]
-        end
-      end)
-      |> decode_clauses()
-
-    clauses ++ bad_digit_clause()
+    alphabet
+    |> Stream.with_index()
+    |> Enum.flat_map(fn {encoding, value} = pair ->
+         if encoding in ?A..?Z do
+           [pair, {encoding - ?A + ?a, value}]
+         else
+           [pair]
+         end
+       end)
+    |> decode_clauses()
   end
 
   defp decode_mixed_clauses(first, second) do
     first_clauses = decode_clauses(first)
     second_clauses = decode_clauses(second) ++ bad_digit_clause()
-
     join_clause =
       quote do
         encoding ->
@@ -210,13 +200,12 @@ defmodule Base do
             unquote(second_clauses)
           end
       end
-
     first_clauses ++ join_clause
   end
 
   defp decode_clauses(alphabet) do
     for {encoding, value} <- alphabet do
-      [clause] = quote(do: (unquote(encoding) -> unquote(value)))
+      [clause] = quote do: (unquote(encoding) -> unquote(value))
       clause
     end
   end
@@ -225,13 +214,14 @@ defmodule Base do
     quote do
       c ->
         raise ArgumentError,
-              "non-alphabet digit found: #{inspect(<<c>>, binaries: :as_strings)} (byte #{c})"
+              "non-alphabet digit found: #{inspect <<c>>, binaries: :as_strings} (byte #{c})"
     end
   end
 
-  defp maybe_pad(body, "", _, _), do: body
-  defp maybe_pad(body, tail, false, _), do: body <> tail
-
+  defp maybe_pad(body, "", _, _),
+    do: body
+  defp maybe_pad(body, tail, false, _),
+    do: body <> tail
   defp maybe_pad(body, tail, _, group_size) do
     case group_size - rem(byte_size(tail), group_size) do
       ^group_size -> body <> tail
@@ -514,7 +504,7 @@ defmodule Base do
 
   """
   @spec url_decode64!(binary, keyword) :: binary
-  def url_decode64!(string, opts \\ []) when is_binary(string) do
+  def url_decode64!(string, opts \\ []) when is_binary(string)  do
     pad? = Keyword.get(opts, :padding, true)
     string |> remove_ignored(opts[:ignore]) |> do_decode64url(pad?)
   end
@@ -779,7 +769,6 @@ defmodule Base do
   end
 
   defp remove_ignored(string, nil), do: string
-
   defp remove_ignored(string, :whitespace) do
     for <<char::8 <- string>>, char not in '\s\t\r\n', into: <<>>, do: <<char::8>>
   end
@@ -796,75 +785,39 @@ defmodule Base do
 
   for {case, fun} <- enc16 do
     defp do_encode16(unquote(case), data) do
-      split = 8 * div(byte_size(data), 8)
+      split =  8 * div(byte_size(data), 8)
       <<main::size(split)-binary, rest::binary>> = data
-
       main =
         for <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8 <- main>>, into: <<>> do
-          <<
-            unquote(fun)(c1)::16,
-            unquote(fun)(c2)::16,
-            unquote(fun)(c3)::16,
-            unquote(fun)(c4)::16,
-            unquote(fun)(c5)::16,
-            unquote(fun)(c6)::16,
-            unquote(fun)(c7)::16,
-            unquote(fun)(c8)::16
-          >>
+          <<unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16, unquote(fun)(c4)::16,
+            unquote(fun)(c5)::16, unquote(fun)(c6)::16,
+            unquote(fun)(c7)::16, unquote(fun)(c8)::16>>
         end
-
       case rest do
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8>> ->
-          <<
-            main::binary,
-            unquote(fun)(c1)::16,
-            unquote(fun)(c2)::16,
-            unquote(fun)(c3)::16,
-            unquote(fun)(c4)::16,
-            unquote(fun)(c5)::16,
-            unquote(fun)(c6)::16,
-            unquote(fun)(c7)::16
-          >>
-
+          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16, unquote(fun)(c4)::16,
+            unquote(fun)(c5)::16, unquote(fun)(c6)::16,
+            unquote(fun)(c7)::16>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8>> ->
-          <<
-            main::binary,
-            unquote(fun)(c1)::16,
-            unquote(fun)(c2)::16,
-            unquote(fun)(c3)::16,
-            unquote(fun)(c4)::16,
-            unquote(fun)(c5)::16,
-            unquote(fun)(c6)::16
-          >>
-
+          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16, unquote(fun)(c4)::16,
+            unquote(fun)(c5)::16, unquote(fun)(c6)::16>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8>> ->
-          <<
-            main::binary,
-            unquote(fun)(c1)::16,
-            unquote(fun)(c2)::16,
-            unquote(fun)(c3)::16,
-            unquote(fun)(c4)::16,
-            unquote(fun)(c5)::16
-          >>
-
+          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16, unquote(fun)(c4)::16,
+            unquote(fun)(c5)::16>>
         <<c1::8, c2::8, c3::8, c4::8>> ->
-          <<
-            main::binary,
-            unquote(fun)(c1)::16,
-            unquote(fun)(c2)::16,
-            unquote(fun)(c3)::16,
-            unquote(fun)(c4)::16
-          >>
-
+          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16, unquote(fun)(c4)::16>>
         <<c1::8, c2::8, c3::8>> ->
-          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16, unquote(fun)(c3)::16>>
-
+          <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16,
+            unquote(fun)(c3)::16>>
         <<c1::8, c2::8>> ->
           <<main::binary, unquote(fun)(c1)::16, unquote(fun)(c2)::16>>
-
         <<c1::8>> ->
           <<main::binary, unquote(fun)(c1)::16>>
-
         <<>> ->
           main
       end
@@ -883,50 +836,27 @@ defmodule Base do
 
   for {case, fun} <- dec16 do
     defp do_decode16(unquote(case), string) do
-      split = 8 * div(byte_size(string), 8)
+      split =  8 * div(byte_size(string), 8)
       <<main::size(split)-binary, rest::binary>> = string
-
       main =
         for <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8 <- main>>, into: <<>> do
-          <<
-            unquote(fun)(c1)::4,
-            unquote(fun)(c2)::4,
-            unquote(fun)(c3)::4,
-            unquote(fun)(c4)::4,
-            unquote(fun)(c5)::4,
-            unquote(fun)(c6)::4,
-            unquote(fun)(c7)::4,
-            unquote(fun)(c8)::4
-          >>
+          <<unquote(fun)(c1)::4, unquote(fun)(c2)::4,
+            unquote(fun)(c3)::4, unquote(fun)(c4)::4,
+            unquote(fun)(c5)::4, unquote(fun)(c6)::4,
+            unquote(fun)(c7)::4, unquote(fun)(c8)::4>>
         end
-
       case rest do
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::4,
-            unquote(fun)(c2)::4,
-            unquote(fun)(c3)::4,
-            unquote(fun)(c4)::4,
-            unquote(fun)(c5)::4,
-            unquote(fun)(c6)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::4, unquote(fun)(c2)::4,
+            unquote(fun)(c3)::4, unquote(fun)(c4)::4,
+            unquote(fun)(c5)::4, unquote(fun)(c6)::4>>
         <<c1::8, c2::8, c3::8, c4::8>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::4,
-            unquote(fun)(c2)::4,
-            unquote(fun)(c3)::4,
-            unquote(fun)(c4)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::4, unquote(fun)(c2)::4,
+            unquote(fun)(c3)::4, unquote(fun)(c4)::4>>
         <<c1::8, c2::8>> ->
           <<main::bits, unquote(fun)(c1)::4, unquote(fun)(c2)::4>>
-
         <<_::8>> ->
           raise ArgumentError, "odd-length string"
-
         <<>> ->
           main
       end
@@ -949,47 +879,29 @@ defmodule Base do
     end
 
     defp unquote(do_encode)(<<>>, _), do: <<>>
-
     defp unquote(do_encode)(data, pad?) do
-      split = 6 * div(byte_size(data), 6)
+      split =  6 * div(byte_size(data), 6)
       <<main::size(split)-binary, rest::binary>> = data
-
-      main =
-        for <<c1::12, c2::12, c3::12, c4::12 <- main>>, into: <<>> do
-          <<
-            unquote(pair)(c1)::16,
-            unquote(pair)(c2)::16,
-            unquote(pair)(c3)::16,
-            unquote(pair)(c4)::16
-          >>
-        end
-
-      tail =
-        case rest do
-          <<c1::12, c2::12, c3::12, c::4>> ->
-            <<
-              unquote(pair)(c1)::16,
-              unquote(pair)(c2)::16,
-              unquote(pair)(c3)::16,
-              unquote(char)(bsl(c, 2))::8
-            >>
-
-          <<c1::12, c2::12, c3::8>> ->
-            <<unquote(pair)(c1)::16, unquote(pair)(c2)::16, unquote(pair)(bsl(c3, 4))::16>>
-
-          <<c1::12, c2::12>> ->
-            <<unquote(pair)(c1)::16, unquote(pair)(c2)::16>>
-
-          <<c1::12, c2::4>> ->
-            <<unquote(pair)(c1)::16, unquote(char)(bsl(c2, 2))::8>>
-
-          <<c1::8>> ->
-            <<unquote(pair)(bsl(c1, 4))::16>>
-
-          <<>> ->
-            <<>>
-        end
-
+      main = for <<c1::12, c2::12, c3::12, c4::12 <- main>>, into: <<>> do
+        <<unquote(pair)(c1)::16, unquote(pair)(c2)::16,
+          unquote(pair)(c3)::16, unquote(pair)(c4)::16>>
+      end
+      tail = case rest do
+        <<c1::12, c2::12, c3::12, c::4>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16, unquote(pair)(c3)::16,
+            unquote(char)(bsl(c, 2))::8>>
+        <<c1::12, c2::12, c3::8>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16,
+            unquote(pair)(bsl(c3, 4))::16>>
+        <<c1::12, c2::12>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16>>
+        <<c1::12, c2::4>> ->
+          <<unquote(pair)(c1)::16, unquote(char)(bsl(c2, 2))::8>>
+        <<c1::8>> ->
+          <<unquote(pair)(bsl(c1, 4))::16>>
+        <<>> ->
+          <<>>
+      end
       maybe_pad(main, tail, pad?, 4)
     end
   end
@@ -1003,106 +915,49 @@ defmodule Base do
     end
 
     defp unquote(do_decode)(<<>>, _), do: <<>>
-
     defp unquote(do_decode)(string, pad?) do
       segs = div(byte_size(string) + 7, 8) - 1
       <<main::size(segs)-binary-unit(64), rest::binary>> = string
-
       main =
         for <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8 <- main>>, into: <<>> do
-          <<
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            unquote(fun)(c6)::6,
-            unquote(fun)(c7)::6,
-            unquote(fun)(c8)::6
-          >>
+          <<unquote(fun)(c1)::6, unquote(fun)(c2)::6, unquote(fun)(c3)::6,
+            unquote(fun)(c4)::6, unquote(fun)(c5)::6, unquote(fun)(c6)::6,
+            unquote(fun)(c7)::6, unquote(fun)(c8)::6>>
         end
-
       case rest do
         <<c1::8, c2::8, ?=, ?=>> ->
           <<main::bits, unquote(fun)(c1)::6, bsr(unquote(fun)(c2), 4)::2>>
-
         <<c1::8, c2::8, c3::8, ?=>> ->
-          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6, bsr(unquote(fun)(c3), 2)::4>>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            bsr(unquote(fun)(c3), 2)::4>>
         <<c1::8, c2::8, c3::8, c4::8>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, ?=, ?=>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            bsr(unquote(fun)(c6), 4)::2
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6, unquote(fun)(c5)::6,
+            bsr(unquote(fun)(c6), 4)::2>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, ?=>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            unquote(fun)(c6)::6,
-            bsr(unquote(fun)(c7), 2)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6, unquote(fun)(c5)::6,
+            unquote(fun)(c6)::6, bsr(unquote(fun)(c7), 2)::4>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            unquote(fun)(c6)::6,
-            unquote(fun)(c7)::6,
-            unquote(fun)(c8)::6
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6, unquote(fun)(c5)::6,
+            unquote(fun)(c6)::6, unquote(fun)(c7)::6, unquote(fun)(c8)::6>>
         <<c1::8, c2::8>> when not pad? ->
           <<main::bits, unquote(fun)(c1)::6, bsr(unquote(fun)(c2), 4)::2>>
-
         <<c1::8, c2::8, c3::8>> when not pad? ->
-          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6, bsr(unquote(fun)(c3), 2)::4>>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            bsr(unquote(fun)(c3), 2)::4>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8>> when not pad? ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            bsr(unquote(fun)(c6), 4)::2
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6, unquote(fun)(c5)::6,
+            bsr(unquote(fun)(c6), 4)::2>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8>> when not pad? ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::6,
-            unquote(fun)(c2)::6,
-            unquote(fun)(c3)::6,
-            unquote(fun)(c4)::6,
-            unquote(fun)(c5)::6,
-            unquote(fun)(c6)::6,
-            bsr(unquote(fun)(c7), 2)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::6, unquote(fun)(c2)::6,
+            unquote(fun)(c3)::6, unquote(fun)(c4)::6, unquote(fun)(c5)::6,
+            unquote(fun)(c6)::6, bsr(unquote(fun)(c7), 2)::4>>
         _ ->
           raise ArgumentError, "incorrect padding"
       end
@@ -1126,44 +981,28 @@ defmodule Base do
     end
 
     defp unquote(do_encode)(_, <<>>, _), do: <<>>
-
     defp unquote(do_encode)(unquote(case), data, pad?) do
-      split = 5 * div(byte_size(data), 5)
+      split =  5 * div(byte_size(data), 5)
       <<main::size(split)-binary, rest::binary>> = data
-
       main =
         for <<c1::10, c2::10, c3::10, c4::10 <- main>>, into: <<>> do
-          <<
-            unquote(pair)(c1)::16,
-            unquote(pair)(c2)::16,
-            unquote(pair)(c3)::16,
-            unquote(pair)(c4)::16
-          >>
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16,
+            unquote(pair)(c3)::16, unquote(pair)(c4)::16>>
         end
-
-      tail =
-        case rest do
-          <<c1::10, c2::10, c3::10, c4::2>> ->
-            <<
-              unquote(pair)(c1)::16,
-              unquote(pair)(c2)::16,
-              unquote(pair)(c3)::16,
-              unquote(char)(bsl(c4, 3))::8
-            >>
-
-          <<c1::10, c2::10, c3::4>> ->
-            <<unquote(pair)(c1)::16, unquote(pair)(c2)::16, unquote(char)(bsl(c3, 1))::8>>
-
-          <<c1::10, c2::6>> ->
-            <<unquote(pair)(c1)::16, unquote(pair)(bsl(c2, 4))::16>>
-
-          <<c1::8>> ->
-            <<unquote(pair)(bsl(c1, 2))::16>>
-
-          <<>> ->
-            <<>>
-        end
-
+      tail = case rest do
+        <<c1::10, c2::10, c3::10, c4::2>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16,
+            unquote(pair)(c3)::16, unquote(char)(bsl(c4, 3))::8>>
+        <<c1::10, c2::10, c3::4>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(c2)::16,
+            unquote(char)(bsl(c3, 1))::8>>
+        <<c1::10, c2::6>> ->
+          <<unquote(pair)(c1)::16, unquote(pair)(bsl(c2, 4))::16>>
+        <<c1::8>> ->
+          <<unquote(pair)(bsl(c1, 2))::16>>
+        <<>> ->
+          <<>>
+      end
       maybe_pad(main, tail, pad?, 8)
     end
   end
@@ -1182,103 +1021,47 @@ defmodule Base do
     defp unquote(do_decode)(unquote(case), string, pad?) do
       segs = div(byte_size(string) + 7, 8) - 1
       <<main::size(segs)-binary-unit(64), rest::binary>> = string
-
       main =
         for <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8 <- main>>, into: <<>> do
-          <<
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            unquote(fun)(c5)::5,
-            unquote(fun)(c6)::5,
-            unquote(fun)(c7)::5,
-            unquote(fun)(c8)::5
-          >>
+          <<unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            unquote(fun)(c5)::5, unquote(fun)(c6)::5,
+            unquote(fun)(c7)::5, unquote(fun)(c8)::5>>
         end
-
       case rest do
         <<c1::8, c2::8, ?=, ?=, ?=, ?=, ?=, ?=>> ->
           <<main::bits, unquote(fun)(c1)::5, bsr(unquote(fun)(c2), 2)::3>>
-
         <<c1::8, c2::8, c3::8, c4::8, ?=, ?=, ?=, ?=>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            bsr(unquote(fun)(c4), 4)::1
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, bsr(unquote(fun)(c4), 4)::1>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, ?=, ?=, ?=>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            bsr(unquote(fun)(c5), 1)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            bsr(unquote(fun)(c5), 1)::4>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, ?=>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            unquote(fun)(c5)::5,
-            unquote(fun)(c6)::5,
-            bsr(unquote(fun)(c7), 3)::2
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            unquote(fun)(c5)::5, unquote(fun)(c6)::5,
+            bsr(unquote(fun)(c7), 3)::2>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8, c8::8>> ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            unquote(fun)(c5)::5,
-            unquote(fun)(c6)::5,
-            unquote(fun)(c7)::5,
-            unquote(fun)(c8)::5
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            unquote(fun)(c5)::5, unquote(fun)(c6)::5,
+            unquote(fun)(c7)::5, unquote(fun)(c8)::5>>
         <<c1::8, c2::8>> when not pad? ->
           <<main::bits, unquote(fun)(c1)::5, bsr(unquote(fun)(c2), 2)::3>>
-
         <<c1::8, c2::8, c3::8, c4::8>> when not pad? ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            bsr(unquote(fun)(c4), 4)::1
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, bsr(unquote(fun)(c4), 4)::1>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8>> when not pad? ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            bsr(unquote(fun)(c5), 1)::4
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            bsr(unquote(fun)(c5), 1)::4>>
         <<c1::8, c2::8, c3::8, c4::8, c5::8, c6::8, c7::8>> when not pad? ->
-          <<
-            main::bits,
-            unquote(fun)(c1)::5,
-            unquote(fun)(c2)::5,
-            unquote(fun)(c3)::5,
-            unquote(fun)(c4)::5,
-            unquote(fun)(c5)::5,
-            unquote(fun)(c6)::5,
-            bsr(unquote(fun)(c7), 3)::2
-          >>
-
+          <<main::bits, unquote(fun)(c1)::5, unquote(fun)(c2)::5,
+            unquote(fun)(c3)::5, unquote(fun)(c4)::5,
+            unquote(fun)(c5)::5, unquote(fun)(c6)::5,
+            bsr(unquote(fun)(c7), 3)::2>>
         _ ->
           raise ArgumentError, "incorrect padding"
       end

lib/elixir/lib/behaviour.ex

@@ -1,19 +1,15 @@
 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 `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.
   """
 
-  @moduledoc deprecated: "Use @callback and @macrocallback attributes instead"
-
   @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
 
@@ -90,9 +82,8 @@ defmodule Behaviour 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"
-
+        "use the @callback and @macrocallback module attributes. See the " <>
+        "documentation for Module for more information on these attributes"
       IO.warn(warning)
 
       @doc false
@@ -101,20 +92,14 @@ defmodule Behaviour do
       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

lib/elixir/lib/bitwise.ex

@@ -6,9 +6,9 @@ defmodule Bitwise do
   operators. For example:
 
       iex> use Bitwise
-      iex> bnot(1) # named
+      iex> bnot 1   # named
       -2
-      iex> 1 &&& 1 # operator
+      iex> 1 &&& 1  # operator
       1
 
   If you prefer to use only operators or skip them, you can
@@ -29,10 +29,7 @@ defmodule Bitwise do
   All bitwise 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 +37,14 @@ 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)
@@ -66,9 +60,8 @@ defmodule Bitwise do
       1
 
   """
-  @doc guard: true
   defmacro bnot(expr) do
-    quote(do: :erlang.bnot(unquote(expr)))
+    quote do: :erlang.bnot(unquote(expr))
   end
 
   @doc """
@@ -80,9 +73,8 @@ defmodule Bitwise do
       1
 
   """
-  @doc guard: true
   defmacro ~~~expr do
-    quote(do: :erlang.bnot(unquote(expr)))
+    quote do: :erlang.bnot(unquote(expr))
   end
 
   @doc """
@@ -92,9 +84,8 @@ defmodule Bitwise do
       1
 
   """
-  @doc guard: true
   defmacro band(left, right) do
-    quote(do: :erlang.band(unquote(left), unquote(right)))
+    quote do: :erlang.band(unquote(left), unquote(right))
   end
 
   @doc """
@@ -104,9 +95,8 @@ defmodule Bitwise do
       1
 
   """
-  @doc guard: true
   defmacro left &&& right do
-    quote(do: :erlang.band(unquote(left), unquote(right)))
+    quote do: :erlang.band(unquote(left), unquote(right))
   end
 
   @doc """
@@ -116,9 +106,8 @@ defmodule Bitwise do
       11
 
   """
-  @doc guard: true
   defmacro bor(left, right) do
-    quote(do: :erlang.bor(unquote(left), unquote(right)))
+    quote do: :erlang.bor(unquote(left), unquote(right))
   end
 
   @doc """
@@ -128,9 +117,8 @@ defmodule Bitwise do
       11
 
   """
-  @doc guard: true
   defmacro left ||| right do
-    quote(do: :erlang.bor(unquote(left), unquote(right)))
+    quote do: :erlang.bor(unquote(left), unquote(right))
   end
 
   @doc """
@@ -140,9 +128,8 @@ defmodule Bitwise do
       10
 
   """
-  @doc guard: true
   defmacro bxor(left, right) do
-    quote(do: :erlang.bxor(unquote(left), unquote(right)))
+    quote do: :erlang.bxor(unquote(left), unquote(right))
   end
 
   @doc """
@@ -152,9 +139,8 @@ defmodule Bitwise do
       10
 
   """
-  @doc guard: true
   defmacro left ^^^ right do
-    quote(do: :erlang.bxor(unquote(left), unquote(right)))
+    quote do: :erlang.bxor(unquote(left), unquote(right))
   end
 
   @doc """
@@ -170,9 +156,8 @@ defmodule Bitwise do
       -1
 
   """
-  @doc guard: true
   defmacro bsl(left, right) do
-    quote(do: :erlang.bsl(unquote(left), unquote(right)))
+    quote do: :erlang.bsl(unquote(left), unquote(right))
   end
 
   @doc """
@@ -188,9 +173,8 @@ defmodule Bitwise do
       -1
 
   """
-  @doc guard: true
   defmacro left <<< right do
-    quote(do: :erlang.bsl(unquote(left), unquote(right)))
+    quote do: :erlang.bsl(unquote(left), unquote(right))
   end
 
   @doc """
@@ -206,9 +190,8 @@ defmodule Bitwise do
       -4
 
   """
-  @doc guard: true
   defmacro bsr(left, right) do
-    quote(do: :erlang.bsr(unquote(left), unquote(right)))
+    quote do: :erlang.bsr(unquote(left), unquote(right))
   end
 
   @doc """
@@ -224,8 +207,7 @@ defmodule Bitwise do
       -4
 
   """
-  @doc guard: true
   defmacro left >>> right do
-    quote(do: :erlang.bsr(unquote(left), unquote(right)))
+    quote do: :erlang.bsr(unquote(left), unquote(right))
   end
 end

lib/elixir/lib/calendar.ex

@@ -17,15 +17,11 @@ defmodule Calendar do
   """
 
   @type year :: integer
-  @type month :: pos_integer
-  @type day :: pos_integer
-  @type week :: pos_integer
-  @type day_of_week :: non_neg_integer
-  @type era :: non_neg_integer
-
-  @type hour :: non_neg_integer
-  @type minute :: non_neg_integer
-  @type second :: non_neg_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.
@@ -39,9 +35,14 @@ defmodule Calendar do
   @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+00:00T00:00.000000 in ISO 8601 notation (also
-  known as midnight 1 January BC 1 of the proleptic Gregorian calendar).
+  This is the amount 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}
 
@@ -58,10 +59,10 @@ defmodule Calendar do
   @type calendar :: module
 
   @typedoc "The time zone ID according to the IANA tz database (e.g. Europe/Zurich)"
-  @type time_zone :: String.t()
+  @type time_zone :: String.t
 
   @typedoc "The time zone abbreviation (e.g. CET or CEST or BST etc.)"
-  @type zone_abbr :: String.t()
+  @type zone_abbr :: String.t
 
   @typedoc "The time zone UTC offset in seconds"
   @type utc_offset :: integer
@@ -73,65 +74,16 @@ defmodule Calendar do
   @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
-        }
+  @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
-        }
+  @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
-        }
-
-  @typedoc """
-  Specifies the time zone database for calendar operations.
-
-  Many functions in the `DateTime` module require a time zone database.
-  By default, it uses the default time zone database returned by
-  `Calendar.get_time_zone_database/0`, which defaults to
-  `Calendar.UTCOnlyTimeZoneDatabase` which only handles "Etc/UTC"
-  datetimes and returns `{:error, :utc_only_time_zone_database}`
-  for any other time zone.
-
-  Other time zone databases (including ones provided by packages)
-  can be configure as default either via configuration:
-
-      config :elixir, :time_zone_database, CustomTimeZoneDatabase
-
-  or by calling `Calendar.put_time_zone_database/1`.
-
-  See `Calendar.TimeZoneDatabase` for more information on custom
-  time zone databases.
-  """
-  @type time_zone_database :: module()
+  @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.
@@ -139,12 +91,7 @@ defmodule Calendar do
   @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.
+  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
@@ -155,80 +102,46 @@ defmodule Calendar do
   @doc """
   Calculates the day of the week from the given `year`, `month`, and `day`.
   """
-  @callback day_of_week(year, month, day) :: day_of_week()
-
-  @doc """
-  Calculates the day of the year from the given `year`, `month`, and `day`.
-  """
-  @callback day_of_year(year, month, day) :: non_neg_integer()
-
-  @doc """
-  Calculates the quarter of the year from the given `year`, `month`, and `day`.
-  """
-  @callback quarter_of_year(year, month, day) :: non_neg_integer()
-
-  @doc """
-  Calculates the year and era from the given `year`.
-  """
-  @callback year_of_era(year) :: {year, era}
-
-  @doc """
-  Calculates the day and era from the given `year`, `month`, and `day`.
-  """
-  @callback day_of_era(year, month, day) :: {non_neg_integer(), era}
+  @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()
+  @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()
+  @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()
+  @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()
+  @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.
+  Converts the given datetime (with time zone) into the `t:iso_days` format.
   """
-  @callback naive_datetime_to_iso_days(year, month, day, hour, minute, second, microsecond) ::
-              iso_days
+  @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.
+  Converts `t:iso_days` to the Calendar's datetime format.
   """
-  @callback naive_datetime_from_iso_days(iso_days) ::
-              {year, month, day, hour, minute, second, microsecond}
+  @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.
+  Converts the given time to the `t:day_fraction` format.
   """
   @callback time_to_day_fraction(hour, minute, second, microsecond) :: day_fraction
 
   @doc """
-  Converts `t:day_fraction/0` to the Calendar's time format.
+  Converts `t:day_fraction` to the Calendar's time format.
   """
   @callback time_from_day_fraction(day_fraction) :: {hour, minute, second, microsecond}
 
@@ -275,46 +188,9 @@ defmodule Calendar do
   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
+  @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}
-
-  @doc """
-  Sets the current time zone database.
-  """
-  @doc since: "1.8.0"
-  @spec put_time_zone_database(time_zone_database()) :: :ok
-  def put_time_zone_database(database) do
-    Application.put_env(:elixir, :time_zone_database, database)
-  end
-
-  @doc """
-  Gets the current time zone database.
-  """
-  @doc since: "1.8.0"
-  @spec get_time_zone_database() :: time_zone_database()
-  def get_time_zone_database() do
-    Application.get_env(:elixir, :time_zone_database, Calendar.UTCOnlyTimeZoneDatabase)
+    calendar1.day_rollover_relative_to_midnight_utc() == calendar2.day_rollover_relative_to_midnight_utc()
   end
 end

lib/elixir/lib/calendar/date.ex

@@ -3,8 +3,8 @@ defmodule Date do
   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` (see `Kernel.sigil_D/2`) sigil:
+  New dates can be built with the `new/3` function or using the `~D`
+  sigil:
 
       iex> ~D[2000-01-01]
       ~D[2000-01-01]
@@ -25,19 +25,19 @@ defmodule Date do
 
   Developers should avoid creating the Date structs directly
   and instead rely on the functions provided by this module as well
-  as the ones in third-party calendar libraries.
+  as the ones in 3rd party calendar libraries.
 
   ## Comparing dates
 
-  Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
+  Comparisons in Elixir using `==`, `>`, `<` 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
+  or retrieving the amount of days betweens instants. For example, if there
+  is an interest in computing the amount of days from the Unix epoch
   (1970-01-01):
 
       iex> Date.diff(~D[2010-04-17], ~D[1970-01-01])
@@ -53,12 +53,8 @@ defmodule Date do
   @enforce_keys [:year, :month, :day]
   defstruct [:year, :month, :day, calendar: Calendar.ISO]
 
-  @type t :: %__MODULE__{
-          year: Calendar.year(),
-          month: Calendar.month(),
-          day: Calendar.day(),
-          calendar: Calendar.calendar()
-        }
+  @type t :: %Date{year: Calendar.year, month: Calendar.month,
+                   day: Calendar.day, calendar: Calendar.calendar}
 
   @doc """
   Returns a range of dates.
@@ -74,6 +70,9 @@ defmodule Date do
       iex> Date.range(~D[1999-01-01], ~D[2000-01-01])
       #DateRange<~D[1999-01-01], ~D[2000-01-01]>
 
+      iex> Date.range(~N[2000-01-01 09:00:00], ~D[1999-01-01])
+      #DateRange<~N[2000-01-01 09:00:00], ~D[1999-01-01]>
+
   A range of dates implements the `Enumerable` protocol, which means
   functions in the `Enum` module can be used to work with
   ranges:
@@ -85,11 +84,10 @@ defmodule Date do
       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
+
+  @spec range(Calendar.date, Calendar.date) :: Date.Range.t
+  def range(%{calendar: calendar} = first, %{calendar: calendar} = last) do
     {first_days, _} = to_iso_days(first)
     {last_days, _} = to_iso_days(last)
 
@@ -97,11 +95,12 @@ defmodule Date do
       first: first,
       last: last,
       first_in_iso_days: first_days,
-      last_in_iso_days: last_days
+      last_in_iso_days: last_days,
     }
   end
 
-  def range(%Date{}, %Date{}) do
+  def range(%{calendar: _, year: _, month: _, day: _},
+            %{calendar: _, year: _, month: _, day: _}) do
     raise ArgumentError, "both dates must have matching calendars"
   end
 
@@ -115,23 +114,22 @@ defmodule Date do
       true
 
   """
-  @doc since: "1.4.0"
-  @spec utc_today(Calendar.calendar()) :: t
+  @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)
+    {: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()
+    |> DateTime.utc_now
+    |> DateTime.to_date
   end
 
   @doc """
-  Returns `true` if the year in the given `date` is a leap year.
+  Returns true if the year in the given `date` is a leap year.
 
   ## Examples
 
@@ -147,8 +145,7 @@ defmodule Date do
       true
 
   """
-  @doc since: "1.4.0"
-  @spec leap_year?(Calendar.date()) :: boolean()
+  @spec leap_year?(Calendar.date) :: boolean()
   def leap_year?(date)
 
   def leap_year?(%{calendar: calendar, year: year}) do
@@ -168,31 +165,13 @@ defmodule Date do
       29
 
   """
-  @doc since: "1.4.0"
-  @spec days_in_month(Calendar.date()) :: Calendar.day()
+  @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.
 
@@ -214,8 +193,7 @@ defmodule Date do
       {:error, :invalid_date}
 
   """
-  @spec new(Calendar.year(), Calendar.month(), Calendar.day(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
+  @spec new(Calendar.year, Calendar.month, Calendar.day) :: {: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}}
@@ -233,11 +211,9 @@ defmodule Date do
       "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()
+  @spec to_string(Calendar.date) :: String.t
   def to_string(date)
 
   def to_string(%{calendar: calendar, year: year, month: month, day: day}) do
@@ -248,8 +224,6 @@ defmodule Date do
   Parses the extended "Dates" format described by
   [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
 
-  The year parsed by this function is limited to four digits.
-
   ## Examples
 
       iex> Date.from_iso8601("2015-01-23")
@@ -262,34 +236,24 @@ defmodule Date do
       {:error, :invalid_date}
 
   """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
+  @spec from_iso8601(String.t) :: {: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
+  def from_iso8601(<<year::4-bytes, ?-, month::2-bytes, ?-, day::2-bytes>>, calendar) do
+    with {year, ""} <- Integer.parse(year),
+         {month, ""} <- Integer.parse(month),
+         {day, ""} <- Integer.parse(day) do
+      with {:ok, date} <- new(year, month, day, Calendar.ISO),
+           do: convert(date, calendar)
     else
       _ -> {:error, :invalid_format}
     end
   end
 
+  def from_iso8601(<<_::binary>>, _calendar) do
+    {:error, :invalid_format}
+  end
+
   @doc """
   Parses the extended "Dates" format described by
   [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
@@ -302,16 +266,14 @@ defmodule Date do
       ~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
+  @spec from_iso8601!(String.t) :: 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)}"
+        raise ArgumentError, "cannot parse #{inspect string} as date, reason: #{inspect reason}"
     end
   end
 
@@ -338,20 +300,12 @@ defmodule Date do
       "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
+  @spec to_iso8601(Calendar.date, :extended | :basic) :: String.t
+  def to_iso8601(date, format \\ :extended) when format in [:basic, :extended] do
+    %{year: year, month: month, day: day} = convert!(date, Calendar.ISO)
     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.
 
@@ -368,7 +322,7 @@ defmodule Date do
       {2000, 1, 1}
 
   """
-  @spec to_erl(Calendar.date()) :: :calendar.date()
+  @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}
@@ -389,11 +343,12 @@ defmodule Date do
       {:error, :invalid_date}
 
   """
-  @spec from_erl(:calendar.date(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
+  @spec from_erl(:calendar.date) :: {: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)
+    with {:ok, date} <- new(year, month, day, Calendar.ISO),
+         do: convert(date, calendar)
   end
 
   @doc """
@@ -407,15 +362,13 @@ defmodule Date do
       ** (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
+  @spec from_erl!(:calendar.date) :: t
+  def from_erl!(tuple) do
+    case from_erl(tuple) do
       {:ok, value} ->
         value
-
       {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(tuple)} to date, reason: #{inspect(reason)}"
+        raise ArgumentError, "cannot convert #{inspect tuple} to date, reason: #{inspect reason}"
     end
   end
 
@@ -442,19 +395,15 @@ defmodule Date do
       :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
-
+  @spec compare(Calendar.date, Calendar.date) :: :lt | :eq | :gt
+  def compare(%{calendar: calendar, year: year1, month: month1, day: day1},
+              %{calendar: calendar, year: year2, month: month2, day: day2}) do
     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
@@ -464,16 +413,16 @@ defmodule Date do
       end
     else
       raise ArgumentError, """
-      cannot compare #{inspect(date1)} with #{inspect(date2)}.
+      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) to resolve this ambiguity
+      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`.
+  Converts the given `date` from it's calendar to the given `calendar`.
 
   Returns `{:ok, date}` if the calendars are compatible,
   or `{:error, :incompatible_calendars}` if they are not.
@@ -490,20 +439,16 @@ defmodule Date do
       {: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}
+  @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}
@@ -524,24 +469,20 @@ defmodule Date do
       %Date{calendar: Calendar.Holocene, year: 12000, month: 1, day: 1}
 
   """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.date(), Calendar.calendar()) :: t
+  @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)}"
+        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
+  The days are counted as gregorian days. The date is returned in the same
   calendar as it was given in.
 
   ## Examples
@@ -550,34 +491,21 @@ defmodule Date do
       ~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.ISO} = date, days) do
-    %{year: year, month: month, day: day} = date
-
-    {year, month, day} =
-      Calendar.ISO.date_to_iso_days(year, month, day)
-      |> Kernel.+(days)
-      |> Calendar.ISO.date_from_iso_days()
-
-    %Date{calendar: Calendar.ISO, year: year, month: month, day: day}
-  end
-
+  @spec add(Calendar.date, integer()) :: t
   def add(%{calendar: calendar} = date, days) do
-    {base_days, fraction} = to_iso_days(date)
-    from_iso_days({base_days + days, fraction}, calendar)
+    {iso_days_days, fraction} = to_iso_days(date)
+    from_iso_days({iso_days_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`
+  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.
 
@@ -587,20 +515,16 @@ defmodule Date do
       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)
+  @spec diff(Calendar.date, Calendar.date) :: integer
+  def diff(%{calendar: Calendar.ISO, year: year1, month: month1, day: day1},
+           %{calendar: Calendar.ISO, year: year2, month: month2, day: day2}) do
+    Calendar.ISO.date_to_iso_days_days(year1, month1, day1) -
+      Calendar.ISO.date_to_iso_days_days(year2, month2, day2)
   end
 
   def diff(%{calendar: calendar1} = date1, %{calendar: calendar2} = date2) do
@@ -609,24 +533,21 @@ defmodule Date do
       {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"
+      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}}
+    {Calendar.ISO.date_to_iso_days_days(year, month, day), {0, 86400000000}}
   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)
+    {year, month, day} = Calendar.ISO.date_from_iso_days_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}
@@ -647,118 +568,15 @@ defmodule Date do
       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()) :: Calendar.day()
+  @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
 
-  @doc """
-  Calculates the day of the year of a given `date`.
-
-  Returns the day of the year as an integer. For the ISO 8601
-  calendar (the default), it is an integer from 1 to 366.
-
-  ## Examples
-
-      iex> Date.day_of_year(~D[2016-01-01])
-      1
-      iex> Date.day_of_year(~D[2016-11-01])
-      306
-      iex> Date.day_of_year(~D[-0015-10-30])
-      303
-      iex> Date.day_of_year(~D[2004-12-31])
-      366
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_year(Calendar.date()) :: Calendar.day()
-  def day_of_year(date)
-
-  def day_of_year(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.day_of_year(year, month, day)
-  end
-
-  @doc """
-  Calculates the quarter of the year of a given `date`.
-
-  Returns the day of the year as an integer. For the ISO 8601
-  calendar (the default), it is an integer from 1 to 4.
-
-  ## Examples
-
-      iex> Date.quarter_of_year(~D[2016-10-31])
-      4
-      iex> Date.quarter_of_year(~D[2016-01-01])
-      1
-      iex> Date.quarter_of_year(~N[2016-04-01 01:23:45])
-      2
-      iex> Date.quarter_of_year(~D[-0015-09-30])
-      3
-
-  """
-  @doc since: "1.8.0"
-  @spec quarter_of_year(Calendar.date()) :: non_neg_integer()
-  def quarter_of_year(date)
-
-  def quarter_of_year(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.quarter_of_year(year, month, day)
-  end
-
-  @doc """
-  Calculates the year-of-era and era for a given
-  calendar year.
-
-  Returns a tuple `{year, era}` representing the
-  year within the era and the era number.
-
-  ## Examples
-
-      iex> Date.year_of_era(~D[0001-01-01])
-      {1, 1}
-      iex> Date.year_of_era(~D[0000-12-31])
-      {1, 0}
-      iex> Date.year_of_era(~D[-0001-01-01])
-      {2, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec year_of_era(Calendar.date()) :: {Calendar.year(), non_neg_integer()}
-  def year_of_era(date)
-
-  def year_of_era(%{calendar: calendar, year: year}) do
-    calendar.year_of_era(year)
-  end
-
-  @doc """
-  Calculates the day-of-era and era for a given
-  calendar `date`.
-
-  Returns a tuple `{day, era}` representing the
-  day within the era and the era number.
-
-  ## Examples
-
-    iex> Date.day_of_era(~D[0001-01-01])
-    {1, 1}
-    iex> Date.day_of_era(~D[0000-12-31])
-    {1, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_era(Calendar.date()) :: {Calendar.day(), non_neg_integer()}
-  def day_of_era(date)
-
-  def day_of_era(%{calendar: calendar, year: year, month: month, day: day}) do
-    calendar.day_of_era(year, month, day)
-  end
-
   ## Helpers
 
   defimpl String.Chars do

lib/elixir/lib/calendar/date_range.ex

@@ -12,29 +12,17 @@ defmodule Date.Range do
   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()
+  @type t :: %__MODULE__{first: Date.t, last: Date.t,
+                         first_in_iso_days: Calendar.days,
+                         last_in_iso_days: Calendar.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
+    def member?(%{first: %{calendar: calendar, year: first_year, month: first_month, day: first_day},
+                  last: %{calendar: calendar, year: last_year, month: last_month, day: last_day},
+                  first_in_iso_days: first_in_iso_days, last_in_iso_days: last_in_iso_days},
+                %Date{calendar: calendar, year: year, month: month, day: day}) do
       first = {first_year, first_month, first_day}
       last = {last_year, last_month, last_day}
       date = {year, month, day}
@@ -50,45 +38,13 @@ defmodule Date.Range do
       {:ok, false}
     end
 
-    def count(%{first_in_iso_days: first, last_in_iso_days: last}) do
-      {:ok, abs(first - last) + 1}
+    def count(%Date.Range{first_in_iso_days: first_in_iso_days, last_in_iso_days: last_in_iso_days}) do
+      {:ok, abs(first_in_iso_days - last_in_iso_days) + 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?)
+    def reduce(%Date.Range{first_in_iso_days: first_in_iso_days, last_in_iso_days: last_in_iso_days,
+                           first: %{calendar: calendar}}, acc, fun) do
+      reduce(first_in_iso_days, last_in_iso_days, acc, fun, calendar, first_in_iso_days <= last_in_iso_days)
     end
 
     defp reduce(_x, _y, {:halt, acc}, _fun, _calendar, _up?) do
@@ -100,26 +56,24 @@ defmodule Date.Range do
     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?)
+      reduce(x + 1, y, fun.(date_from_iso_days_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?)
+      reduce(x - 1, y, fun.(date_from_iso_days_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)
+    defp date_from_iso_days_days(days, Calendar.ISO) do
+      {year, month, day} = Calendar.ISO.date_from_iso_days_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}})
-
+    defp date_from_iso_days_days(days, calendar) do
+      {year, month, day, _, _, _, _} = calendar.naive_datetime_from_iso_days({days, {0, 86400000000}})
       %Date{year: year, month: month, day: day, calendar: calendar}
     end
   end

lib/elixir/lib/calendar/iso.ex

@@ -1,6 +1,6 @@
 defmodule Calendar.ISO do
   @moduledoc """
-  A calendar implementation that follows to ISO 8601.
+  A calendar implementation that follows to ISO8601.
 
   This calendar implements the proleptic Gregorian calendar and
   is therefore compatible with the calendar used in most countries
@@ -8,75 +8,29 @@ defmodule Calendar.ISO do
   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
+  Note that while ISO8601 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
+  @unix_epoch 62167219200
+  @unix_start 1_000_000 * -@unix_epoch
+  @unix_end 315569519999999999 - @unix_epoch * 1_000_000
+  @unix_range_microseconds @unix_start..@unix_end
 
-  @type year :: -9999..9999
+  @type year :: 0..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
+  @seconds_per_day 24 * 60 * 60 # Note that this does _not_ handle leap seconds.
   @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
-
-  # The ISO epoch starts, in this implementation,
-  # with ~D[0000-01-01]. Era "1" starts
-  # on ~D[0001-01-01] which is 366 days later.
-  @iso_epoch 366
-
-  @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.
+  Returns the `t:Calendar.iso_days` format of the specified date.
 
   ## Examples
 
@@ -86,53 +40,34 @@ defmodule Calendar.ISO do
       {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()
+  @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)}
+    {date_to_iso_days_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.
+  Converts the `t:Calendar.iso_days` 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}})
+      iex> Calendar.ISO.naive_datetime_from_iso_days({730485, {0, 86400}})
       {2000, 1, 1, 0, 0, 0, {0, 6}}
-      iex> Calendar.ISO.naive_datetime_from_iso_days({730_485, {43200, 86400}})
+      iex> Calendar.ISO.naive_datetime_from_iso_days({730485, {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
+  @spec naive_datetime_from_iso_days(Calendar.iso_days) ::
+        {Calendar.year, Calendar.month, Calendar.day,
+         Calendar.hour, Calendar.minute, Calendar.second, Calendar.microsecond}
   def naive_datetime_from_iso_days({days, day_fraction}) do
-    {year, month, day} = date_from_iso_days(days)
+    {year, month, day} = date_from_iso_days_days(days)
     {hour, minute, second, microsecond} = time_from_day_fraction(day_fraction)
     {year, month, day, hour, minute, second, microsecond}
   end
@@ -148,21 +83,14 @@ defmodule Calendar.ISO do
       {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()
+  @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}
+    {0, 86400000000}
   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}
+    {combined_seconds * @microseconds_per_second + microsecond, @seconds_per_day * @microseconds_per_second}
   end
 
   @doc """
@@ -170,73 +98,44 @@ defmodule Calendar.ISO do
 
   ## Examples
 
-      iex> Calendar.ISO.time_from_day_fraction({1, 2})
+      iex> Calendar.ISO.time_from_day_fraction({1,2})
       {12, 0, 0, {0, 6}}
-      iex> Calendar.ISO.time_from_day_fraction({13, 24})
+      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({0, _}) do
-    {0, 0, 0, {0, 6}}
-  end
-
+  @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 = divide_by_parts_per_day(parts_in_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)
-
+    total_microseconds = div(parts_in_day * @seconds_per_day * @microseconds_per_second, 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
 
-  defp divide_by_parts_per_day(parts_in_day, @parts_per_day), do: parts_in_day
-
-  defp divide_by_parts_per_day(parts_in_day, parts_per_day),
-    do: div(parts_in_day * @parts_per_day, parts_per_day)
-
   # Converts year, month, day to count of days since 0000-01-01.
   @doc false
-  def date_to_iso_days(0, 1, 1) do
+  def date_to_iso_days_days(0, 1, 1) do
     0
   end
-
-  def date_to_iso_days(1970, 1, 1) do
-    719_528
+  def date_to_iso_days_days(1970, 1, 1) do
+    719528
   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
+  def date_to_iso_days_days(year, month, day) when year <= 9999 do
+    :calendar.date_to_gregorian_days(year, month, day)
   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}
+  def date_from_iso_days_days(days) when days <= 3652424 do
+    :calendar.gregorian_days_to_date(days)
   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
+    mod = int1 - (div * int2)
+    {div, mod}
   end
 
   @doc """
@@ -256,37 +155,17 @@ defmodule Calendar.ISO do
       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.
 
@@ -300,14 +179,11 @@ defmodule Calendar.ISO do
       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)
+  def leap_year?(year) when is_integer(year) and year >= 0 do
+    rem(year, 4) === 0 and (rem(year, 100) > 0 or rem(year, 400) === 0)
   end
 
   @doc """
@@ -319,168 +195,29 @@ defmodule Calendar.ISO do
 
       iex> Calendar.ISO.day_of_week(2016, 10, 31)
       1
-      iex> Calendar.ISO.day_of_week(2016, 11, 1)
+      iex> Calendar.ISO.day_of_week(2016, 11, 01)
       2
-      iex> Calendar.ISO.day_of_week(2016, 11, 2)
+      iex> Calendar.ISO.day_of_week(2016, 11, 02)
       3
-      iex> Calendar.ISO.day_of_week(2016, 11, 3)
+      iex> Calendar.ISO.day_of_week(2016, 11, 03)
       4
-      iex> Calendar.ISO.day_of_week(2016, 11, 4)
+      iex> Calendar.ISO.day_of_week(2016, 11, 04)
       5
-      iex> Calendar.ISO.day_of_week(2016, 11, 5)
+      iex> Calendar.ISO.day_of_week(2016, 11, 05)
       6
-      iex> Calendar.ISO.day_of_week(2016, 11, 6)
+      iex> Calendar.ISO.day_of_week(2016, 11, 06)
       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
-    iso_days_to_day_of_week(date_to_iso_days(year, month, day))
-  end
-
-  defp iso_days_to_day_of_week(iso_days) do
-    Integer.mod(iso_days + 5, 7) + 1
-  end
-
-  @doc """
-  Calculates the day of the year from the given `year`, `month`, and `day`.
-
-  It is an integer from 1 to 366.
-
-  ## Examples
-
-      iex> Calendar.ISO.day_of_year(2016, 1, 31)
-      31
-      iex> Calendar.ISO.day_of_year(-99, 2, 1)
-      32
-      iex> Calendar.ISO.day_of_year(2018, 2, 28)
-      59
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_year(year, month, day) :: 1..366
-  @impl true
-  def day_of_year(year, month, day)
-      when is_integer(year) and is_integer(month) and is_integer(day) do
-    true = day <= days_in_month(year, month)
-    days_before_month(month) + leap_day_offset(year, month) + day
-  end
-
-  @doc """
-  Calculates the quarter of the year from the given `year`, `month`, and `day`.
-
-  It is an integer from 1 to 4.
-
-  ## Examples
-
-      iex> Calendar.ISO.quarter_of_year(2016, 1, 31)
-      1
-      iex> Calendar.ISO.quarter_of_year(2016, 4, 3)
-      2
-      iex> Calendar.ISO.quarter_of_year(-99, 9, 31)
-      3
-      iex> Calendar.ISO.quarter_of_year(2018, 12, 28)
-      4
-
-  """
-  @doc since: "1.8.0"
-  @spec quarter_of_year(year, month, day) :: 1..4
-  @impl true
-  def quarter_of_year(year, month, day)
-      when is_integer(year) and is_integer(month) and is_integer(day) do
-    div(month - 1, 3) + 1
-  end
-
-  @doc """
-  Calculates the year and era from the given `year`.
-
-  The ISO calendar has two eras: the current era which
-  starts in year 1 and is defined as era "1". And a
-  second era for those years less than 1 defined as
-  era "0".
-
-  ## Examples
-
-      iex> Calendar.ISO.year_of_era(1)
-      {1, 1}
-      iex> Calendar.ISO.year_of_era(2018)
-      {2018, 1}
-      iex> Calendar.ISO.year_of_era(0)
-      {1, 0}
-      iex> Calendar.ISO.year_of_era(-1)
-      {2, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec year_of_era(year) :: {year, era :: 0..1}
-  @impl true
-  def year_of_era(year) when is_integer(year) and year > 0 do
-    {year, 1}
-  end
-
-  def year_of_era(year) when is_integer(year) and year < 1 do
-    {abs(year) + 1, 0}
-  end
-
-  @doc """
-  Calculates the day and era from the given `year`, `month`, and `day`.
-
-  ## Examples
-
-      iex> Calendar.ISO.day_of_era(0, 1, 1)
-      {366, 0}
-      iex> Calendar.ISO.day_of_era(1, 1, 1)
-      {1, 1}
-      iex> Calendar.ISO.day_of_era(0, 12, 31)
-      {1, 0}
-      iex> Calendar.ISO.day_of_era(0, 12, 30)
-      {2, 0}
-      iex> Calendar.ISO.day_of_era(-1, 12, 31)
-      {367, 0}
-
-  """
-  @doc since: "1.8.0"
-  @spec day_of_era(year, month, day) :: {day :: pos_integer(), era :: 0..1}
-  @impl true
-  def day_of_era(year, month, day)
-      when is_integer(year) and is_integer(month) and is_integer(day) and year > 0 do
-    day = date_to_iso_days(year, month, day) - @iso_epoch + 1
-    {day, 1}
-  end
-
-  def day_of_era(year, month, day)
-      when is_integer(year) and is_integer(month) and is_integer(day) and year < 1 do
-    day = abs(date_to_iso_days(year, month, day) - @iso_epoch)
-    {day, 0}
+    :calendar.day_of_the_week(year, month, day)
   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, microsecond, format \\ :extended)
 
   def time_to_string(hour, minute, second, {_, 0}, format) do
     time_to_string_format(hour, minute, second, format)
@@ -501,170 +238,49 @@ defmodule Calendar.ISO do
 
   @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, :extended), do: date_to_string(year, month, day)
   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> time_zone = "Europe/Berlin"
-      iex> Calendar.ISO.datetime_to_string(2017, 8, 1, 1, 2, 3, {4, 5}, time_zone, "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}, time_zone, "CDT", 3600, 3600)
-      "2017-08-01 01:02:03.00000+02:00 CDT Europe/Berlin"
-
-      iex> time_zone = "America/Los_Angeles"
-      iex> Calendar.ISO.datetime_to_string(2015, 2, 28, 1, 2, 3, {4, 5}, time_zone, "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}, time_zone, "PDT", -28800, 3600)
-      "2015-02-28 01:02:03.00000-07:00 PDT America/Los_Angeles"
-
+  Convers the datetime (with time zone) into a string.
   """
-  @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) <>
-      " " <>
+  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))
+    year <= 9999 and :calendar.valid_date(year, month, day)
   end
 
-  @doc """
-  Determines if the date given is valid according to the proleptic Gregorian calendar.
-
-  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.
-  Leap seconds are not supported as well by the built-in Calendar.ISO.
-
-  ## Examples
-
-      iex> Calendar.ISO.valid_time?(10, 50, 25, {3006, 6})
-      true
-      iex> Calendar.ISO.valid_time?(23, 59, 60, {0, 0})
-      false
-      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.second(), 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..59 and microsecond in 0..999_999 and
-      precision in 0..6
+    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_midnight_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)
@@ -687,13 +303,9 @@ defmodule Calendar.ISO do
   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", max(count - byte_size(num), 0)) <> num
-  end
-
   defp zero_pad(val, count) do
-    "-" <> zero_pad(-val, count)
+    num = Integer.to_string(val)
+    :binary.copy("0", count - byte_size(num)) <> num
   end
 
   ## Helpers
@@ -701,12 +313,11 @@ defmodule Calendar.ISO do
   @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)
+      {date, time} = :calendar.gregorian_seconds_to_datetime(seconds)
       {:ok, date, time, {microseconds, precision}}
     else
       {:error, :invalid_unix_time}
@@ -714,13 +325,14 @@ defmodule Calendar.ISO do
   end
 
   defp precision_for_unit(unit) do
-    subsecond = div(System.convert_time_unit(1, :second, unit), 10)
+    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(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)
 
@@ -735,37 +347,14 @@ defmodule Calendar.ISO do
   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)
+  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" <>
+  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
@@ -775,11 +364,9 @@ defmodule Calendar.ISO 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
@@ -795,34 +382,35 @@ defmodule Calendar.ISO do
 
   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}
+  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(""),
+    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
+  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}
+      {((hour * 60) + min) * 60 * sign, rest}
     else
       _ -> :error
     end
@@ -830,8 +418,8 @@ defmodule Calendar.ISO do
 
   @doc false
   def iso_days_to_unit({days, {parts, ppd}}, unit) do
-    day_microseconds = days * @parts_per_day
-    microseconds = divide_by_parts_per_day(parts, ppd)
+    day_microseconds = days * @seconds_per_day * @microseconds_per_second
+    microseconds = div(parts * @seconds_per_day * @microseconds_per_second, ppd)
     System.convert_time_unit(day_microseconds + microseconds, :microsecond, unit)
   end
 
@@ -839,7 +427,6 @@ defmodule Calendar.ISO do
   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
@@ -852,145 +439,10 @@ defmodule Calendar.ISO do
   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

lib/elixir/lib/calendar/naive_datetime.ex

@@ -4,8 +4,7 @@ defmodule NaiveDateTime do
 
   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` (see `Kernel.sigil_N/2`) sigil:
+  built with the `new/2` and `new/7` functions or using the `~N` sigil:
 
       iex> ~N[2000-01-01 23:00:07]
       ~N[2000-01-01 23:00:07]
@@ -28,27 +27,32 @@ defmodule NaiveDateTime do
   `NaiveDateTime` is not validated against a time zone, such errors
   would go unnoticed.
 
+  The functions on 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 third-party calendar libraries.
+  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
+  Comparisons in Elixir using `==`, `>`, `<` 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
+  date times or retrieving the amount of seconds betweens instants.
+  For example, if there is an interest in computing the amount 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)
+      iex> NaiveDateTime.add(~N[1970-01-01 00:00:00], 1271512800)
       ~N[2010-04-17 14:00:00]
 
   Those functions are optimized to deal with common epochs, such
@@ -56,27 +60,11 @@ defmodule NaiveDateTime do
   """
 
   @enforce_keys [:year, :month, :day, :hour, :minute, :second]
-  defstruct [
-    :year,
-    :month,
-    :day,
-    :hour,
-    :minute,
-    :second,
-    microsecond: {0, 0},
-    calendar: Calendar.ISO
-  ]
+  defstruct [:year, :month, :day, :hour, :minute, :second, 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()
-        }
+  @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.
@@ -91,30 +79,21 @@ defmodule NaiveDateTime do
       true
 
   """
-  @doc since: "1.4.0"
-  @spec utc_now(Calendar.calendar()) :: t
+  @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
-    }
+      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()
+    |> DateTime.utc_now
+    |> DateTime.to_naive
   end
 
   @doc """
@@ -141,58 +120,25 @@ defmodule NaiveDateTime do
       {: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, 60, 999_999)
+      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
+  @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) do
+    with {:ok, date} <- Date.new(year, month, day, calendar),
+         {:ok, time} <- Time.new(hour, minute, second, microsecond, calendar),
+         do: new(date, time)
   end
 
   @doc """
@@ -204,32 +150,22 @@ defmodule NaiveDateTime do
       {:ok, ~N[2010-01-13 23:00:07.005]}
 
   """
-  @spec new(Date.t(), Time.t()) :: {:ok, t}
+  @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}
+  def new(%Date{calendar: calendar, year: year, month: month, day: day},
+          %Time{calendar: calendar, hour: hour, minute: minute, second: second, microsecond: microsecond}) do
+    {:ok, %NaiveDateTime{calendar: calendar, year: year, month: month, day: day,
+                         hour: hour, minute: minute, second: second, microsecond: microsecond}}
   end
 
   @doc """
   Adds a specified amount of time to a `NaiveDateTime`.
 
-  Accepts an `amount_to_add` in any `unit` available from `t:System.time_unit/0`.
-  Negative values will move backwards in time.
+  Accepts an `integer` in any `unit` available from `t:System.time_unit/0`.
+  Negative values will be move backwards in time.
+
+  This operation is only possible if both calendars are convertible to `Calendar.ISO`.
 
   ## Examples
 
@@ -251,36 +187,21 @@ defmodule NaiveDateTime do
 
       # 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]
+      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)
+      iex> NaiveDateTime.add(~N[0000-01-01 00:00:00], 63579428950)
       ~N[2014-10-02 00:29:10]
 
-  Passing a `Datetime` automatically converts it to `NaiveDateTime`,
-  discarding 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.add(dt, 21, :second)
-      ~N[2000-02-29 23:00:28]
-
   """
-  @doc since: "1.4.0"
-  @spec add(Calendar.naive_datetime(), integer, System.time_unit()) :: t
-  def add(
-        %{microsecond: {_, precision}, calendar: calendar} = naive_datetime,
-        amount_to_add,
-        unit \\ :second
-      )
-      when is_integer(amount_to_add) do
+  @spec add(t, integer, System.time_unit) :: t
+  def add(%NaiveDateTime{microsecond: {_, precision}, calendar: calendar} = naive_datetime,
+          integer, unit \\ :second) when is_integer(integer) do
     ppd = System.convert_time_unit(86400, :second, unit)
-
     naive_datetime
     |> to_iso_days()
-    |> Calendar.ISO.add_day_fraction_to_iso_days(amount_to_add, ppd)
+    |> Calendar.ISO.add_day_fraction_to_iso_days(integer, ppd)
     |> from_iso_days(calendar, precision)
   end
 
@@ -302,26 +223,18 @@ defmodule NaiveDateTime do
       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(Calendar.naive_datetime(), Calendar.naive_datetime(), System.time_unit()) :: integer
-  def diff(
-        %{calendar: calendar1} = naive_datetime1,
-        %{calendar: calendar2} = naive_datetime2,
-        unit \\ :second
-      ) do
-    if not Calendar.compatible_calendars?(calendar1, calendar2) 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"
+  @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)
@@ -329,56 +242,6 @@ defmodule NaiveDateTime do
     units1 - units2
   end
 
-  @doc """
-  Returns the given naive datetime with the microsecond field truncated to the
-  given precision (`:microsecond`, `:millisecond` or `:second`).
-
-  The given naive datetime is returned unchanged if it already has lower precision
-  than the given precision.
-
-  ## 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
-
-  def truncate(
-        %{
-          calendar: calendar,
-          year: year,
-          month: month,
-          day: day,
-          hour: hour,
-          minute: minute,
-          second: second,
-          microsecond: microsecond
-        },
-        precision
-      ) do
-    %NaiveDateTime{
-      calendar: calendar,
-      year: year,
-      month: month,
-      day: day,
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: Calendar.truncate(microsecond, precision)
-    }
-  end
-
   @doc """
   Converts a `NaiveDateTime` into a `Date`.
 
@@ -391,24 +254,11 @@ defmodule NaiveDateTime do
       ~D[2002-01-13]
 
   """
-  @spec to_date(Calendar.naive_datetime()) :: Date.t()
+  @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
 
-  def to_date(%{
-        year: year,
-        month: month,
-        day: day,
-        calendar: calendar,
-        hour: _,
-        minute: _,
-        second: _,
-        microsecond: _
-      }) do
-    %Date{year: year, month: month, day: day, calendar: calendar}
-  end
-
   @doc """
   Converts a `NaiveDateTime` into `Time`.
 
@@ -421,42 +271,9 @@ defmodule NaiveDateTime do
       ~T[23:00:07]
 
   """
-  @spec to_time(Calendar.naive_datetime()) :: 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
-
-  def to_time(%{
-        year: _,
-        month: _,
-        day: _,
-        calendar: calendar,
-        hour: hour,
-        minute: minute,
-        second: second,
-        microsecond: microsecond
-      }) do
-    %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    }
+  @spec to_time(t) :: Time.t
+  def to_time(%NaiveDateTime{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: calendar}) do
+    %Time{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: calendar}
   end
 
   @doc """
@@ -468,8 +285,6 @@ defmodule NaiveDateTime do
       "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:
@@ -481,18 +296,11 @@ defmodule NaiveDateTime do
       "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
+  @spec to_string(Calendar.naive_datetime) :: String.t
+  def to_string(naive_datetime)
 
+  def to_string(%{calendar: calendar, year: year, month: month, day: day,
+                  hour: hour, minute: minute, second: second, microsecond: microsecond}) do
     calendar.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
   end
 
@@ -500,17 +308,17 @@ defmodule NaiveDateTime do
   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
+  Timezone 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.
 
-  The year parsed by this function is limited to four digits and,
-  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.
-  Note leap seconds are not supported by the built-in Calendar.ISO.
+  Time representations with reduced accuracy are not supported.
+
+  Note that while ISO8601 allows datetimes to specify 24:00:00 as the
+  zero hour of the next day, this notation is not supported by Elixir.
 
   ## Examples
 
@@ -555,39 +363,30 @@ defmodule NaiveDateTime do
       {:error, :invalid_format}
 
   """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
+  @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),
+  def from_iso8601(<<year::4-bytes, ?-, month::2-bytes, ?-, day::2-bytes, sep,
+                     hour::2-bytes, ?:, min::2-bytes, ?:, sec::2-bytes, rest::binary>>, calendar) when sep in [?\s, ?T] do
+    with {year, ""} <- Integer.parse(year),
+         {month, ""} <- Integer.parse(month),
+         {day, ""} <- Integer.parse(day),
+         {hour, ""} <- Integer.parse(hour),
+         {min, ""} <- Integer.parse(min),
+         {sec, ""} <- Integer.parse(sec),
          {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, iso_naive_dt} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO) do
-        convert(iso_naive_dt, calendar)
-      end
+      with {:ok, utc_date} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO),
+           do: convert(utc_date, calendar)
     else
       _ -> {:error, :invalid_format}
     end
   end
 
+  def from_iso8601(<<_::binary>>, _calendar) do
+    {:error, :invalid_format}
+  end
+
   @doc """
   Parses the extended "Date and time of day" format described by
   [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
@@ -604,15 +403,13 @@ defmodule NaiveDateTime do
       ** (ArgumentError) cannot parse "2015-01-23P23:50:07" as naive datetime, reason: :invalid_format
 
   """
-  @spec from_iso8601!(String.t(), Calendar.calendar()) :: t
+  @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)}"
+        raise ArgumentError, "cannot parse #{inspect string} as naive datetime, reason: #{inspect reason}"
     end
   end
 
@@ -637,7 +434,7 @@ defmodule NaiveDateTime do
       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
+  This function can also be used to convert a DateTime to ISO8601 without
   the time zone information:
 
       iex> dt = %DateTime{year: 2000, month: 2, day: 29, zone_abbr: "CET",
@@ -647,39 +444,26 @@ defmodule NaiveDateTime do
       "2000-02-29T23:00:07"
 
   """
-  @spec to_iso8601(Calendar.naive_datetime(), :basic | :extended) :: String.t()
+  @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
-    )
+  def to_iso8601(%{year: year, month: month, day: day,
+                   hour: hour, minute: minute, second: second, microsecond: microsecond, calendar:
+    Calendar.ISO}, format) when format in [:basic, :extended] do
+    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
+  def to_iso8601(%{year: _, month: _, day: _,
+                   hour: _, minute: _, second: _, microsecond: _, calendar: _} = naive_datetime, format) when format in [:basic, :extended] do
     naive_datetime
     |> convert!(Calendar.ISO)
     |> to_iso8601(format)
   end
 
+  def to_iso8601(_date, format) do
+    raise ArgumentError, "NaiveDateTime.to_iso8601/2 expects format to be :extended or :basic, got: #{inspect format}"
+  end
+
   @doc """
   Converts a `NaiveDateTime` struct to an Erlang datetime tuple.
 
@@ -704,11 +488,14 @@ defmodule NaiveDateTime do
       {{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)
+  @spec to_erl(t) :: :calendar.datetime
+  def to_erl(naive_datetime)
 
+  @spec to_erl(Calendar.time) :: :calendar.time
+  def to_erl(%{calendar: _, year: _, month: _, day: _,
+               hour: _, minute: _, second: _} = 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
 
@@ -725,20 +512,19 @@ defmodule NaiveDateTime do
       {: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}})
+      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}
+  @spec from_erl(:calendar.datetime, Calendar.microsecond) :: {: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, iso_naive_dt} <- new(year, month, day, hour, minute, second, microsecond),
-         do: convert(iso_naive_dt, calendar)
+    with {:ok, utc_date} <- new(year, month, day, hour, minute, second, microsecond),
+         do: convert(utc_date, calendar)
   end
 
-  @doc """
+   @doc """
   Converts an Erlang datetime tuple to a `NaiveDateTime` struct.
 
   Raises if the datetime is invalid.
@@ -754,15 +540,13 @@ defmodule NaiveDateTime do
       ** (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
-  def from_erl!(tuple, microsecond \\ {0, 0}, calendar \\ Calendar.ISO) do
-    case from_erl(tuple, microsecond, calendar) do
+  @spec from_erl!(:calendar.datetime, Calendar.microsecond) :: t | no_return
+  def from_erl!(tuple, microsecond \\ {0, 0}) do
+    case from_erl(tuple, microsecond) do
       {:ok, value} ->
         value
-
       {:error, reason} ->
-        raise ArgumentError,
-              "cannot convert #{inspect(tuple)} to naive datetime, reason: #{inspect(reason)}"
+        raise ArgumentError, "cannot convert #{inspect tuple} to naive datetime, reason: #{inspect reason}"
     end
   end
 
@@ -794,8 +578,7 @@ defmodule NaiveDateTime do
       :lt
 
   """
-  @doc since: "1.4.0"
-  @spec compare(Calendar.naive_datetime(), Calendar.naive_datetime()) :: :lt | :eq | :gt
+  @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
@@ -805,7 +588,7 @@ defmodule NaiveDateTime do
       end
     else
       raise ArgumentError, """
-      cannot compare #{inspect(naive_datetime1)} with #{inspect(naive_datetime2)}.
+      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
@@ -831,36 +614,11 @@ defmodule NaiveDateTime do
                            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}
+  @spec convert(Calendar.naive_datetime, Calendar.calendar) :: {:ok, t} | {:error, :incompatible_calendars}
+  def convert(%{calendar: calendar, year: year, month: month, day: day,
+                hour: hour, minute: minute, second: second, microsecond: microsecond}, calendar) do
+    {:ok, %NaiveDateTime{calendar: calendar, year: year, month: month, day: day,
+                         hour: hour, minute: minute, second: second, microsecond: microsecond}}
   end
 
   def convert(%{calendar: ndt_calendar, microsecond: {_, precision}} = naive_datetime, calendar) do
@@ -869,7 +627,6 @@ defmodule NaiveDateTime do
         naive_datetime
         |> to_iso_days
         |> from_iso_days(calendar, precision)
-
       {:ok, result_naive_datetime}
     else
       {:error, :incompatible_calendars}
@@ -893,85 +650,41 @@ defmodule NaiveDateTime do
                      hour: 13, minute: 30, second: 15, microsecond: {0, 0}}
 
   """
-  @doc since: "1.5.0"
-  @spec convert!(Calendar.naive_datetime(), Calendar.calendar()) :: t
+  @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"
+        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
+  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}
-    }
+    %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
-
+    def to_string(%{calendar: calendar, year: year, month: month, day: day,
+                    hour: hour, minute: minute, second: second, microsecond: microsecond}) do
       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)
-
+    def inspect(%{calendar: Calendar.ISO, year: year, month: month, day: day,
+                  hour: hour, minute: minute, second: second, microsecond: microsecond}, _) do
+      formatted = Calendar.ISO.naive_datetime_to_string(year, month, day, hour, minute, second, microsecond)
       "~N[" <> formatted <> "]"
     end
 

lib/elixir/lib/calendar/time.ex

@@ -3,8 +3,8 @@ defmodule Time do
   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` (see `Kernel.sigil_T/2`) sigil:
+  New times can be built with the `new/4` function or using the `~T`
+  sigil:
 
       iex> ~T[23:00:07.001]
       ~T[23:00:07.001]
@@ -25,11 +25,11 @@ defmodule Time do
 
   Developers should avoid creating the Time structs directly
   and instead rely on the functions provided by this module as well
-  as the ones in third-party calendar libraries.
+  as the ones in 3rd party calendar libraries.
 
   ## Comparing times
 
-  Comparisons in Elixir using `==/2`, `>/2`, `</2` and similar are structural
+  Comparisons in Elixir using `==`, `>`, `<` and similar are structural
   and based on the `Time` struct fields. For proper comparison between
   times, use the `compare/2` function.
   """
@@ -37,15 +37,8 @@ defmodule Time do
   @enforce_keys [:hour, :minute, :second]
   defstruct [:hour, :minute, :second, microsecond: {0, 0}, calendar: Calendar.ISO]
 
-  @type t :: %__MODULE__{
-          hour: Calendar.hour(),
-          minute: Calendar.minute(),
-          second: Calendar.second(),
-          microsecond: Calendar.microsecond(),
-          calendar: Calendar.calendar()
-        }
-
-  @parts_per_day 86_400_000_000
+  @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.
@@ -57,20 +50,10 @@ defmodule Time do
       true
 
   """
-  @doc since: "1.4.0"
-  @spec utc_now(Calendar.calendar()) :: t
+  @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
-    }
-
+    {:ok, _, {hour, minute, second}, microsecond} = Calendar.ISO.from_unix(:os.system_time, :native)
+    iso_time = %Time{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: Calendar.ISO}
     convert!(iso_time, calendar)
   end
 
@@ -80,10 +63,9 @@ defmodule Time do
   Expects all values to be integers. Returns `{:ok, time}` if each
   entry fits its appropriate range, returns `{:error, reason}` otherwise.
 
-  Microseconds can also be given with a precision, which must be an
-  integer between 0 and 6.
-
-  The built-in calendar does not support leap seconds.
+  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
 
@@ -91,12 +73,18 @@ defmodule Time do
       {: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, 60, 999_999)
+      iex> Time.new(23, 59, 61, 999_999)
       {:error, :invalid_time}
       iex> Time.new(23, 59, 59, 1_000_000)
       {:error, :invalid_time}
@@ -106,13 +94,8 @@ defmodule Time do
       {:error, :invalid_time}
 
   """
-  @spec new(
-          Calendar.hour(),
-          Calendar.minute(),
-          Calendar.second(),
-          Calendar.microsecond() | integer,
-          Calendar.calendar()
-        ) :: {:ok, t} | {:error, atom}
+  @spec new(Calendar.hour, Calendar.minute, Calendar.second, Calendar.microsecond, 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
@@ -121,19 +104,10 @@ defmodule Time do
 
   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
+           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}
-
+        {:ok, %Time{hour: hour, minute: minute, second: second, microsecond: {microsecond, precision}, calendar: calendar}}
       false ->
         {:error, :invalid_time}
     end
@@ -157,16 +131,10 @@ defmodule Time do
       "23:00:00.123456"
 
   """
-  @spec to_string(Calendar.time()) :: String.t()
+  @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
+  def to_string(%{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: calendar}) do
     calendar.time_to_string(hour, minute, second, microsecond)
   end
 
@@ -174,7 +142,7 @@ defmodule Time do
   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
+  Timezone 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
@@ -182,9 +150,8 @@ defmodule Time do
 
   Time representations with reduced accuracy are not supported.
 
-  Note that while ISO 8601 allows times to specify 24:00:00 as the
+  Note that while ISO8601 allows times to specify 24:00:00 as the
   zero hour of the next day, this notation is not supported by Elixir.
-  Leap seconds are not supported as well by the built-in Calendar.ISO.
 
   ## Examples
 
@@ -212,34 +179,30 @@ defmodule Time do
       {:error, :invalid_time}
 
   """
-  @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
+  @spec from_iso8601(String.t) :: {:ok, t} | {:error, atom}
   def from_iso8601(string, calendar \\ Calendar.ISO)
 
-  def from_iso8601(<<?T, rest::binary>>, calendar) do
-    raw_from_iso8601(rest, calendar)
+  def from_iso8601(<<?T, h, rest::binary>>, calendar) when h in ?0..?9 do
+    from_iso8601(<<h, rest::binary>>, 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),
+  def from_iso8601(<<hour::2-bytes, ?:, min::2-bytes, ?:, sec::2-bytes, rest::binary>>, calendar) do
+    with {hour, ""} <- Integer.parse(hour),
+         {min, ""} <- Integer.parse(min),
+         {sec, ""} <- Integer.parse(sec),
          {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
+      with {:ok, utc_time} <- new(hour, min, sec, microsec, Calendar.ISO),
+           do: convert(utc_time, calendar)
     else
       _ -> {:error, :invalid_format}
     end
   end
 
+  def from_iso8601(<<_::binary>>, _calendar) do
+    {:error, :invalid_format}
+  end
+
   @doc """
   Parses the extended "Local time" format described by
   [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).
@@ -254,16 +217,14 @@ defmodule Time do
       ~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
+  @spec from_iso8601!(String.t) :: t
+  def from_iso8601!(string) do
+    case from_iso8601(string) do
       {:ok, value} ->
         value
-
       {:error, reason} ->
-        raise ArgumentError, "cannot parse #{inspect(string)} as time, reason: #{inspect(reason)}"
+        raise ArgumentError, "cannot parse #{inspect string} as time, reason: #{inspect reason}"
     end
   end
 
@@ -290,26 +251,12 @@ defmodule Time do
       "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
-
+  @spec to_iso8601(Calendar.time, :extended | :basic) :: String.t
+  def to_iso8601(time, format \\ :extended) when format in [:extended, :basic] do
+    %{hour: hour, minute: minute, second: second, microsecond: microsecond} = convert!(time, Calendar.ISO)
     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.
 
@@ -325,7 +272,7 @@ defmodule Time do
       {23, 30, 15}
 
   """
-  @spec to_erl(Calendar.time()) :: :calendar.time()
+  @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}
@@ -342,8 +289,7 @@ defmodule Time do
       {:error, :invalid_time}
 
   """
-  @spec from_erl(:calendar.time(), Calendar.microsecond(), Calendar.calendar()) ::
-          {:ok, t} | {:error, atom}
+  @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
@@ -364,73 +310,16 @@ defmodule Time do
       ** (ArgumentError) cannot convert {24, 30, 15} to time, reason: :invalid_time
 
   """
-  @spec from_erl!(:calendar.time(), Calendar.microsecond(), Calendar.calendar()) :: t
+  @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)}"
+        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)
-    total = time_to_microseconds(time) + number
-    parts = Integer.mod(total, @parts_per_day)
-    {hour, minute, second, microsecond} = calendar.time_from_day_fraction({parts, @parts_per_day})
-
-    %Time{
-      hour: hour,
-      minute: minute,
-      second: second,
-      microsecond: microsecond,
-      calendar: calendar
-    }
-  end
-
-  defp time_to_microseconds(%{
-         calendar: Calendar.ISO,
-         hour: 0,
-         minute: 0,
-         second: 0,
-         microsecond: {0, _}
-       }) do
-    0
-  end
-
-  defp time_to_microseconds(time) do
-    iso_days = {0, to_day_fraction(time)}
-    Calendar.ISO.iso_days_to_unit(iso_days, :microsecond)
-  end
-
   @doc """
   Compares two time structs.
 
@@ -458,12 +347,9 @@ defmodule Time do
       :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
-
+  @spec compare(Calendar.time, Calendar.time) :: :lt | :eq | :gt
+  def compare(%{calendar: calendar, hour: hour1, minute: minute1, second: second1, microsecond: {microsecond1, _}},
+              %{calendar: calendar, hour: hour2, minute: minute2, second: second2, microsecond: {microsecond2, _}}) do
     case {{hour1, minute1, second1, microsecond1}, {hour2, minute2, second2, microsecond2}} do
       {first, second} when first > second -> :gt
       {first, second} when first < second -> :lt
@@ -498,46 +384,18 @@ defmodule Time do
       {: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}
+  @spec convert(Calendar.time, Calendar.calendar) :: {:ok, t} | {:error, atom}
+  def convert(%{calendar: calendar, hour: hour, minute: minute, second: second, microsecond: microsecond}, calendar) do
+    {:ok, %Time{calendar: calendar, hour: hour, minute: minute, second: second, microsecond: microsecond}}
   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}
+      |> calendar.time_from_day_fraction
+    {:ok, %Time{calendar: calendar, hour: hour, minute: minute, second: second,
+                microsecond: {microsecond, precision}}}
   end
 
   @doc """
@@ -554,22 +412,18 @@ defmodule Time do
       %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
+  @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)}"
+        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,
+  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
@@ -596,7 +450,7 @@ defmodule Time do
 
       # 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])
+      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)
@@ -605,103 +459,28 @@ defmodule Time do
       -2_000_000
 
   """
-  @doc since: "1.5.0"
-  @spec diff(Calendar.time(), Calendar.time(), System.time_unit()) :: integer
-  def diff(time1, time2, unit \\ :second)
-
-  def diff(
-        %{
-          calendar: Calendar.ISO,
-          hour: hour1,
-          minute: minute1,
-          second: second1,
-          microsecond: {microsecond1, @parts_per_day}
-        },
-        %{
-          calendar: Calendar.ISO,
-          hour: hour2,
-          minute: minute2,
-          second: second2,
-          microsecond: {microsecond2, @parts_per_day}
-        },
-        unit
-      ) do
-    total =
-      (hour1 - hour2) * 3_600_000_000 + (minute1 - minute2) * 60_000_000 +
-        (second1 - second2) * 1_000_000 + (microsecond1 - microsecond2)
-
-    System.convert_time_unit(total, :microsecond, unit)
-  end
-
-  def diff(time1, time2, unit) do
+  @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`).
-
-  The given time is returned unchanged if it already has lower precision than
-  the given precision.
-
-  ## 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
+  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
-
+    def to_string(%{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: calendar}) do
       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
-
+    def inspect(%{hour: hour, minute: minute, second: second, microsecond: microsecond, calendar: Calendar.ISO}, _) do
       "~T[" <> Calendar.ISO.time_to_string(hour, minute, second, microsecond) <> "]"
     end
 

lib/elixir/lib/calendar/time_zone_database.ex

@@ -1,96 +0,0 @@
-defmodule Calendar.TimeZoneDatabase do
-  @moduledoc """
-  This module defines a behaviour for providing time zone data.
-
-  IANA provides time zone data that includes data about different
-  UTC offsets and standard offsets for time zones.
-  """
-
-  @typedoc """
-  A period where a certain combination of UTC offset, standard offset and zone
-  abbreviation is in effect.
-
-  For instance one period could be the summer of 2018 in "Europe/London" where summer time /
-  daylight saving time is in effect and lasts from spring to autumn. At autumn the `std_offset`
-  changes along with the `zone_abbr` so a different period is needed during winter.
-  """
-  @type time_zone_period :: %{
-          optional(any) => any,
-          utc_offset: Calendar.utc_offset(),
-          std_offset: Calendar.std_offset(),
-          zone_abbr: Calendar.zone_abbr()
-        }
-
-  @typedoc """
-  Limit for when a certain time zone period begins or ends.
-
-  A beginning is inclusive. An ending is exclusive. Eg. if a period is from
-  2015-03-29 01:00:00 and until 2015-10-25 01:00:00, the period includes and
-  begins from the begining of 2015-03-29 01:00:00 and lasts until just before
-  2015-10-25 01:00:00.
-
-  A beginning or end for certain periods are infinite. For instance the latest
-  period for time zones without DST or plans to change. However for the purpose
-  of this behaviour they are only used for gaps in wall time where the needed
-  period limits are at a certain time.
-  """
-  @type time_zone_period_limit :: Calendar.naive_datetime()
-
-  @doc """
-  Time zone period for a point in time in UTC for a specific time zone.
-
-  Takes a time zone name and a point in time for UTC and returns a
-  `time_zone_period` for that point in time.
-  """
-  @doc since: "1.8.0"
-  @callback time_zone_period_from_utc_iso_days(Calendar.iso_days(), Calendar.time_zone()) ::
-              {:ok, time_zone_period}
-              | {:error, :time_zone_not_found | :utc_only_time_zone_database}
-
-  @doc """
-  Possible time zone periods for a certain time zone and wall clock date and time.
-
-  When the provided `datetime` is ambiguous a tuple with `:ambiguous` and two possible
-  periods. The periods in the list are sorted with the first element being the one that begins first.
-
-  When the provided `datetime` is in a gap - for instance during the "spring forward" when going
-  from winter time to summer time, a tuple with `:gap` and two periods with limits are returned
-  in a nested tuple. The first nested two-tuple is the period before the gap and a naive datetime
-  with a limit for when the period ends (wall time). The second nested two-tuple is the period
-  just after the gap and a datetime (wall time) for when the period begins just after the gap.
-
-  If there is only a single possible period for the provided `datetime`, the a tuple with `:single`
-  and the `time_zone_period` is returned.
-  """
-  @doc since: "1.8.0"
-  @callback time_zone_periods_from_wall_datetime(Calendar.naive_datetime(), Calendar.time_zone()) ::
-              {:ok, time_zone_period}
-              | {:ambiguous, time_zone_period, time_zone_period}
-              | {:gap, {time_zone_period, time_zone_period_limit},
-                 {time_zone_period, time_zone_period_limit}}
-              | {:error, :time_zone_not_found | :utc_only_time_zone_database}
-end
-
-defmodule Calendar.UTCOnlyTimeZoneDatabase do
-  @moduledoc """
-  Built-in time zone database that works only in Etc/UTC.
-
-  For all other time zones, it returns `{:error, :utc_only_time_zone_database}`.
-  """
-
-  @behaviour Calendar.TimeZoneDatabase
-
-  @impl true
-  def time_zone_period_from_utc_iso_days(_, "Etc/UTC"),
-    do: {:ok, %{std_offset: 0, utc_offset: 0, zone_abbr: "UTC"}}
-
-  def time_zone_period_from_utc_iso_days(_, _),
-    do: {:error, :utc_only_time_zone_database}
-
-  @impl true
-  def time_zone_periods_from_wall_datetime(_, "Etc/UTC"),
-    do: {:ok, %{std_offset: 0, utc_offset: 0, zone_abbr: "UTC"}}
-
-  def time_zone_periods_from_wall_datetime(_, _),
-    do: {:error, :utc_only_time_zone_database}
-end

lib/elixir/lib/code/identifier.ex

@@ -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.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

lib/elixir/lib/code/typespec.ex

@@ -1,416 +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
-
-  defp typespecs_abstract_code(module) do
-    with {module, binary} <- get_module_and_beam(module),
-         {:ok, {_, [debug_info: {:debug_info_v1, backend, data}]}} <-
-           :beam_lib.chunks(binary, [:debug_info]) do
-      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
-    else
-      _ -> :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

lib/elixir/lib/collectable.ex

@@ -41,7 +41,7 @@ defprotocol Collectable do
   implementation for `MapSet`. In this implementation "collecting" elements
   simply means inserting them in the set through `MapSet.put/2`.
 
-      defimpl Collectable, for: MapSet do
+      defimpl Collectable do
         def into(original) do
           collector_fun = fn
             set, {:cont, elem} -> MapSet.put(set, elem)
@@ -79,75 +79,30 @@ end
 
 defimpl Collectable, for: List do
   def into(original) do
-    if original != [] do
-      IO.warn(
-        "the Collectable protocol is deprecated for non-empty lists. The behaviour of " <>
-          "things like Enum.into/2 or \"for\" comprehensions with an :into option is incorrect " <>
-          "when collecting into non-empty lists. If you're collecting into a non-empty keyword " <>
-          "list, consider using Keyword.merge/2 instead. If you're collecting into a non-empty " <>
-          "list, consider concatenating the two lists with the ++ operator."
-      )
-    end
-
-    fun = fn
+    {[], 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

lib/elixir/lib/dict.ex

@@ -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 +9,18 @@ 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 by 2.0
+  # (hard-deprecated in elixir_dispatch)
 
-  @deprecated message
   defmacro __using__(_) do
     # Use this import to guarantee proper code expansion
     import Kernel, except: [size: 1]
 
     quote do
-      message = "Use maps and the Map module instead"
-
-      @deprecated message
       def get(dict, key, default \\ nil) do
         case fetch(dict, key) do
           {:ok, value} -> value
@@ -36,7 +28,6 @@ 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 +35,12 @@ 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
@@ -59,33 +48,28 @@ 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 ->
           case fetch(dict, key) do
@@ -95,49 +79,41 @@ 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 +125,144 @@ 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 ->
           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
+  @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 +271,10 @@ 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 +288,51 @@ 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)
@@ -416,20 +343,18 @@ 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)
@@ -437,6 +362,6 @@ defmodule Dict do
 
   @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

lib/elixir/lib/file/stat.ex

@@ -12,7 +12,7 @@ defmodule File.Stat do
 
     * `size` - size of file in bytes.
 
-    * `type` - `:device | :directory | :regular | :other | :symlink`; the type of the
+    * `type` - `:device | :directory | :regular | :other`; the type of the
       file.
 
     * `access` - `:read | :write | :read_write | :none`; the current system
@@ -53,27 +53,12 @@ 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__{
-          size: non_neg_integer(),
-          type: :device | :directory | :regular | :other | :symlink,
-          access: :read | :write | :read_write | :none,
-          atime: :calendar.datetime(),
-          mtime: :calendar.datetime(),
-          ctime: :calendar.datetime(),
-          mode: non_neg_integer(),
-          links: non_neg_integer(),
-          major_device: non_neg_integer(),
-          minor_device: non_neg_integer(),
-          inode: non_neg_integer(),
-          uid: non_neg_integer(),
-          gid: non_neg_integer()
-        }
+  @type t :: %__MODULE__{}
 
   @doc """
   Converts a `File.Stat` struct to a `:file_info` record.
@@ -86,7 +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

lib/elixir/lib/file/stream.ex

@@ -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
@@ -42,7 +41,6 @@ defmodule File.Stream 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.
@@ -74,19 +70,19 @@ defmodule File.Stream 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
-
-          {:error, reason} ->
-            raise File.Error, reason: reason, action: "stream", path: path
+      start_fun =
+        fn ->
+          case :file.open(path, read_modes(modes)) do
+            {:ok, device} ->
+              if :trim_bom in modes, do: trim_bom(device), else: 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
 
@@ -100,70 +96,44 @@ defmodule File.Stream do
       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
+    def count(%{path: path, line_or_bytes: bytes}) 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)}
-
+          {:ok, div(size, bytes) + if(rem(size, bytes) == 0, do: 0, else: 1)}
         {:error, reason} ->
           raise File.Error, reason: reason, action: "stream", path: path
       end
     end
 
-    def count(_stream) do
-      {:error, __MODULE__}
-    end
-
     def member?(_stream, _term) do
       {:error, __MODULE__}
     end
 
-    def slice(_stream) do
-      {:error, __MODULE__}
+    defp trim_bom(device) do
+      header = IO.binread(device, 4)
+      {:ok, _new_pos} = :file.position(device, bom_length(header))
+      device
     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 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
@@ -173,10 +143,8 @@ defmodule File.Stream 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

lib/elixir/lib/float.ex

@@ -3,46 +3,11 @@ 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/)
-
   """
 
   import Bitwise
 
-  @power_of_2_to_52 4_503_599_627_370_496
+  @power_of_2_to_52 4503599627370496
   @precision_range 0..15
   @type precision_range :: 0..15
 
@@ -88,44 +53,38 @@ 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
   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)
@@ -136,6 +95,9 @@ defmodule Float do
   and therefore the number above is internally represented as 12.51999999,
   which explains the behaviour above.
 
+  This function always returns a float. `Kernel.trunc/1` may be used instead to
+  truncate the result to an integer afterwards.
+
   ## Examples
 
       iex> Float.floor(34.25)
@@ -149,10 +111,6 @@ defmodule Float do
   @spec floor(float, precision_range) :: float
   def floor(number, precision \\ 0)
 
-  def floor(number, 0) when is_float(number) do
-    :math.floor(number)
-  end
-
   def floor(number, precision) when is_float(number) and precision in @precision_range do
     round(number, precision, :floor)
   end
@@ -196,10 +154,6 @@ defmodule Float do
   @spec ceil(float, precision_range) :: float
   def ceil(number, precision \\ 0)
 
-  def ceil(number, 0) when is_float(number) do
-    :math.ceil(number)
-  end
-
   def ceil(number, precision) when is_float(number) and precision in @precision_range do
     round(number, precision, :ceil)
   end
@@ -219,8 +173,6 @@ defmodule Float do
   `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)
@@ -256,36 +208,32 @@ defmodule Float do
   # and could be implemented in the future.
   def round(float, precision \\ 0)
 
-  def round(float, 0) when is_float(float) do
-    float |> :erlang.round() |> :erlang.float()
-  end
-
   def round(float, precision) when is_float(float) and precision in @precision_range do
     round(float, precision, :half_up)
   end
 
-  def round(float, precision) when is_float(float) do
+  def round(number, precision) when is_float(number) do
     raise ArgumentError, invalid_precision_message(precision)
   end
 
-  defp round(0.0, _precision, _rounding), do: 0.0
-
   defp round(float, precision, rounding) do
     <<sign::1, exp::11, significant::52-bitstring>> = <<float::float>>
-    {num, count, _} = decompose(significant, 1)
+    {num, count, _} = decompose(significant)
     count = count - exp + 1023
 
     cond do
-      # Precision beyond 15 digits
-      count >= 104 ->
+      count <= 0 or  # There is no decimal precision
+      (0 == exp and <<0::52>> == significant) -> #zero or minus zero
+        float
+
+      count >= 104 -> # Precision beyond 15 digits
         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 ->
+      count <= precision -> # We are asking more precision than we have
         float
 
       true ->
@@ -312,11 +260,9 @@ defmodule Float do
         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)
@@ -329,7 +275,6 @@ defmodule Float do
 
   defp scale_down(num, den, exp) do
     new_den = den <<< 1
-
     if num < new_den do
       {den >>> 52, exp}
     else
@@ -350,31 +295,29 @@ defmodule Float do
       end
 
     tmp = tmp - @power_of_2_to_52
-    <<tmp::float>> = <<sign::1, exp + 1023::11, tmp::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..104, 1, fn x, acc ->
     defp power_of_10(unquote(x)), do: unquote(acc)
     acc * 10
-  end)
+  end
 
-  Enum.reduce(0..104, 1, fn x, acc ->
+  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
@@ -382,8 +325,6 @@ defmodule Float do
 
   ## Examples
 
-      iex> Float.ratio(0.0)
-      {0, 1}
       iex> Float.ratio(3.14)
       {7070651414971679, 2251799813685248}
       iex> Float.ratio(-3.14)
@@ -398,55 +339,40 @@ defmodule Float do
       {-16, 1}
 
   """
-  @doc since: "1.4.0"
-  @spec ratio(float) :: {integer, pos_integer}
-  def ratio(0.0), do: {0, 1}
-
   def ratio(float) when is_float(float) do
-    case <<float::float>> do
-      <<sign::1, 0::11, significant::52-bitstring>> ->
-        {num, _, den} = decompose(significant, 0)
-        {sign(sign, num), shift_left(den, 1022)}
-
-      <<sign::1, exp::11, significant::52-bitstring>> ->
-        {num, _, den} = decompose(significant, 1)
-        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
+    <<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
   end
 
-  defp decompose(significant, initial) do
-    decompose(significant, 1, 0, 2, 1, initial)
+  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
 
-  @compile {:inline, sign: 2, shift_left: 2}
   defp sign(0, num), do: num
   defp sign(1, num), do: -num
 
-  defp shift_left(num, times), do: num <<< times
+  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}
@@ -487,36 +413,36 @@ defmodule Float do
       "7.0"
 
   """
-  @spec to_string(float) :: String.t()
+  @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))
   end
 
-  @doc false
   # TODO: Remove by 2.0
-  @deprecated "Use Float.to_charlist/1 instead"
+  # (hard-deprecated in elixir_dispatch)
+  @doc false
   def to_char_list(float), do: Float.to_charlist(float)
 
   @doc false
   # TODO: Remove by 2.0
-  @deprecated "Use :erlang.float_to_list/2 instead"
+  # (hard-deprecated in elixir_dispatch)
   def to_char_list(float, options) do
     :erlang.float_to_list(float, expand_compact(options))
   end
 
   @doc false
   # TODO: Remove by 2.0
-  @deprecated "Use :erlang.float_to_binary/2 instead"
+  # (hard-deprecated in elixir_dispatch)
   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)}"
+    "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, true} | t]),  do: [:compact | expand_compact(t)]
+  defp expand_compact([h | t]),                 do: [h | expand_compact(t)]
+  defp expand_compact([]),                      do: []
 end

lib/elixir/lib/function.ex

@@ -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

lib/elixir/lib/gen_event.ex

@@ -4,7 +4,7 @@ defmodule GenEvent do
   # Functions from this module are deprecated in elixir_dispatch.
 
   @moduledoc """
-  A event manager with event handlers behaviour.
+  WARNING: this module is deprecated.
 
   If you are interested in implementing an event manager, please read the
   "Alternatives" section below. If you have to implement an event handler to
@@ -32,7 +32,7 @@ defmodule GenEvent do
   If the use case where you were using GenEvent requires more complex logic,
   [GenStage](https://github.com/elixir-lang/gen_stage) provides a great
   alternative. GenStage is an external Elixir library maintained by the Elixir
-  team; it provides a tool to implement systems that exchange events in a
+  team; it provides tool to implement systems that exchange events in a
   demand-driven way with built-in support for backpressure. See the [GenStage
   documentation](https://hexdocs.pm/gen_stage) for more information.
 
@@ -43,37 +43,31 @@ defmodule GenEvent do
   [`:gen_event`](http://erlang.org/doc/man/gen_event.html) Erlang module.
   """
 
-  @moduledoc deprecated: "Use Erlang/OTP's :gen_event module instead"
-
   @callback init(args :: term) ::
-              {:ok, state}
-              | {:ok, state, :hibernate}
-              | {:error, reason :: any}
-            when state: any
+    {:ok, state} |
+    {:ok, state, :hibernate} |
+    {:error, reason :: any} when state: any
 
   @callback handle_event(event :: term, state :: term) ::
-              {:ok, new_state}
-              | {:ok, new_state, :hibernate}
-              | :remove_handler
-            when new_state: term
+    {:ok, new_state} |
+    {:ok, new_state, :hibernate} |
+    :remove_handler when new_state: term
 
   @callback handle_call(request :: term, state :: term) ::
-              {:ok, reply, new_state}
-              | {:ok, reply, new_state, :hibernate}
-              | {:remove_handler, reply}
-            when reply: term, new_state: term
+    {:ok, reply, new_state} |
+    {:ok, reply, new_state, :hibernate} |
+    {:remove_handler, reply} when reply: term, new_state: term
 
   @callback handle_info(msg :: term, state :: term) ::
-              {:ok, new_state}
-              | {:ok, new_state, :hibernate}
-              | :remove_handler
-            when new_state: term
+    {:ok, new_state} |
+    {:ok, new_state, :hibernate} |
+    :remove_handler when new_state: term
 
-  @callback terminate(reason, state :: term) :: term
-            when reason: :stop | {:stop, term} | :remove_handler | {:error, term} | term
+  @callback terminate(reason, state :: term) ::
+    term when reason: :stop | {:stop, term} | :remove_handler | {:error, term} | term
 
-  @callback code_change(old_vsn, state :: term, extra :: term) :: {:ok, new_state :: term}
-            when old_vsn: term | {:down, term}
+  @callback code_change(old_vsn, state :: term, extra :: term) ::
+    {:ok, new_state :: term} when old_vsn: term | {:down, term}
 
   @type on_start :: {:ok, pid} | {:error, {:already_started, pid}}
 
@@ -85,16 +79,10 @@ defmodule GenEvent do
 
   @type handler :: atom | {atom, term}
 
-  message = "Use one of the alternatives described in the documentation for the GenEvent module"
-
-  @deprecated message
   @doc false
   defmacro __using__(_) do
     %{file: file, line: line} = __CALLER__
-
-    deprecation_message =
-      "the GenEvent module is deprecated, see its documentation for alternatives"
-
+    deprecation_message = "the GenEvent module is deprecated, see its documentation for alternatives"
     :elixir_errors.warn(line, file, deprecation_message)
 
     quote location: :keep do
@@ -114,17 +102,14 @@ defmodule GenEvent do
       def handle_call(msg, state) do
         proc =
           case Process.info(self(), :registered_name) do
-            {_, []} -> self()
+            {_, []}   -> self()
             {_, name} -> name
           end
 
         # We do this to trick Dialyzer to not complain about non-local returns.
         case :erlang.phash2(1, 1) do
-          0 ->
-            raise "attempted to call GenEvent #{inspect(proc)} but no handle_call/2 clause was provided"
-
-          1 ->
-            {:remove_handler, {:bad_call, msg}}
+          0 -> raise "attempted to call GenEvent #{inspect proc} but no handle_call/2 clause was provided"
+          1 -> {:remove_handler, {:bad_call, msg}}
         end
       end
 
@@ -143,24 +128,18 @@ defmodule GenEvent do
         {:ok, state}
       end
 
-      defoverridable init: 1,
-                     handle_event: 2,
-                     handle_call: 2,
-                     handle_info: 2,
-                     terminate: 2,
-                     code_change: 3
+      defoverridable [init: 1, handle_event: 2, handle_call: 2,
+                      handle_info: 2, terminate: 2, code_change: 3]
     end
   end
 
   @doc false
-  @deprecated message
   @spec start_link(options) :: on_start
   def start_link(options \\ []) when is_list(options) do
     do_start(:link, options)
   end
 
   @doc false
-  @deprecated message
   @spec start(options) :: on_start
   def start(options \\ []) when is_list(options) do
     do_start(:nolink, options)
@@ -172,19 +151,15 @@ defmodule GenEvent do
     case Keyword.get(options, :name) do
       nil ->
         :gen.start(GenEvent, mode, @no_callback, [], [])
-
       atom when is_atom(atom) ->
         :gen.start(GenEvent, mode, {:local, atom}, @no_callback, [], [])
-
       {:global, _term} = tuple ->
         :gen.start(GenEvent, mode, tuple, @no_callback, [], [])
-
       {:via, via_module, _term} = tuple when is_atom(via_module) ->
         :gen.start(GenEvent, mode, tuple, @no_callback, [], [])
-
       other ->
         raise ArgumentError, """
-        expected :name option to be one of the following:
+        expected :name option to be one of:
 
           * nil
           * atom
@@ -197,28 +172,26 @@ defmodule GenEvent do
   end
 
   @doc false
-  @deprecated message
-  @spec stream(manager, keyword) :: GenEvent.Stream.t()
+  @spec stream(manager, keyword) :: GenEvent.Stream.t
   def stream(manager, options \\ []) do
-    %GenEvent.Stream{manager: manager, timeout: Keyword.get(options, :timeout, :infinity)}
+    %GenEvent.Stream{
+      manager: manager,
+      timeout: Keyword.get(options, :timeout, :infinity)}
   end
 
   @doc false
-  @deprecated message
   @spec add_handler(manager, handler, term) :: :ok | {:error, term}
   def add_handler(manager, handler, args) do
     rpc(manager, {:add_handler, handler, args})
   end
 
   @doc false
-  @deprecated message
   @spec add_mon_handler(manager, handler, term) :: :ok | {:error, term}
   def add_mon_handler(manager, handler, args) do
     rpc(manager, {:add_mon_handler, handler, args, self()})
   end
 
   @doc false
-  @deprecated message
   @spec notify(manager, term) :: :ok
   def notify(manager, event)
 
@@ -243,28 +216,26 @@ defmodule GenEvent do
   def notify(manager, msg)
       when is_pid(manager)
       when is_atom(manager)
-      when tuple_size(manager) == 2 and is_atom(elem(manager, 0)) and is_atom(elem(manager, 1)) do
+      when tuple_size(manager) == 2 and
+        is_atom(elem(manager, 0)) and is_atom(elem(manager, 1)) do
     send(manager, {:notify, msg})
     :ok
   end
 
   @doc false
-  @deprecated message
   @spec sync_notify(manager, term) :: :ok
   def sync_notify(manager, event) do
     rpc(manager, {:sync_notify, event})
   end
 
   @doc false
-  @deprecated message
   @spec ack_notify(manager, term) :: :ok
   def ack_notify(manager, event) do
     rpc(manager, {:ack_notify, event})
   end
 
   @doc false
-  @deprecated message
-  @spec call(manager, handler, term, timeout) :: term | {:error, term}
+  @spec call(manager, handler, term, timeout) ::  term | {:error, term}
   def call(manager, handler, request, timeout \\ 5000) do
     try do
       :gen.call(manager, self(), {:call, handler, request}, timeout)
@@ -277,35 +248,30 @@ defmodule GenEvent do
   end
 
   @doc false
-  @deprecated message
   @spec remove_handler(manager, handler, term) :: term | {:error, term}
   def remove_handler(manager, handler, args) do
     rpc(manager, {:delete_handler, handler, args})
   end
 
   @doc false
-  @deprecated message
   @spec swap_handler(manager, handler, term, handler, term) :: :ok | {:error, term}
   def swap_handler(manager, handler1, args1, handler2, args2) do
     rpc(manager, {:swap_handler, handler1, args1, handler2, args2})
   end
 
   @doc false
-  @deprecated message
   @spec swap_mon_handler(manager, handler, term, handler, term) :: :ok | {:error, term}
   def swap_mon_handler(manager, handler1, args1, handler2, args2) do
     rpc(manager, {:swap_mon_handler, handler1, args1, handler2, args2, self()})
   end
 
   @doc false
-  @deprecated message
   @spec which_handlers(manager) :: [handler]
   def which_handlers(manager) do
     rpc(manager, :which_handlers)
   end
 
   @doc false
-  @deprecated message
   @spec stop(manager, reason :: term, timeout) :: :ok
   def stop(manager, reason \\ :normal, timeout \\ :infinity) do
     :gen.stop(manager, reason, timeout)
@@ -319,7 +285,7 @@ defmodule GenEvent do
   ## Init callbacks
 
   require Record
-  Record.defrecordp(:handler, [:module, :id, :state, :pid, :ref])
+  Record.defrecordp :handler, [:module, :id, :state, :pid, :ref]
 
   @doc false
   def init_it(starter, :self, name, mod, args, options) do
@@ -328,14 +294,12 @@ defmodule GenEvent do
 
   def init_it(starter, parent, name, _mod, _args, options) do
     Process.put(:"$initial_call", {__MODULE__, :init_it, 6})
-
     debug =
       if function_exported?(:gen, :debug_options, 2) do
         :gen.debug_options(name, options)
       else
         :gen.debug_options(options)
       end
-
     :proc_lib.init_ack(starter, {:ok, self()})
     loop(parent, name(name), [], debug, false)
   end
@@ -345,7 +309,7 @@ defmodule GenEvent do
     fetch_msg(parent, name, handlers, debug, true)
   end
 
-  defp name({:local, name}), do: name
+  defp name({:local, name}),  do: name
   defp name({:global, name}), do: name
   defp name({:via, _, name}), do: name
   defp name(pid) when is_pid(pid), do: pid
@@ -363,14 +327,12 @@ defmodule GenEvent do
   defp fetch_msg(parent, name, handlers, debug, hib) do
     receive do
       {:system, from, req} ->
-        :sys.handle_system_msg(req, from, parent, __MODULE__, debug, [name, handlers, hib], hib)
-
+        :sys.handle_system_msg(req, from, parent, __MODULE__,
+          debug, [name, handlers, hib], hib)
       {:EXIT, ^parent, reason} ->
         server_terminate(reason, parent, handlers, name)
-
       msg when debug == [] ->
         handle_msg(msg, parent, name, handlers, [])
-
       msg ->
         debug = :sys.handle_debug(debug, &print_event/3, name, {:in, msg})
         handle_msg(msg, parent, name, handlers, debug)
@@ -382,78 +344,59 @@ defmodule GenEvent do
       {:notify, event} ->
         {hib, handlers} = server_event(:async, event, handlers, name)
         loop(parent, name, handlers, debug, hib)
-
       {_from, _tag, {:notify, event}} ->
         {hib, handlers} = server_event(:async, event, handlers, name)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:ack_notify, event}} ->
         reply(tag, :ok)
         {hib, handlers} = server_event(:ack, event, handlers, name)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:sync_notify, event}} ->
         {hib, handlers} = server_event(:sync, event, handlers, name)
         reply(tag, :ok)
         loop(parent, name, handlers, debug, hib)
-
       {:DOWN, ref, :process, _pid, reason} = other ->
         case handle_down(ref, reason, handlers, name) do
           {:ok, handlers} ->
             loop(parent, name, handlers, debug, false)
-
           :error ->
             {hib, handlers} = server_info(other, handlers, name)
             loop(parent, name, handlers, debug, hib)
         end
-
       {_from, tag, {:call, handler, query}} ->
         {hib, reply, handlers} = server_call(handler, query, handlers, name)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:add_handler, handler, args}} ->
         {hib, reply, handlers} = server_add_handler(handler, args, handlers)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:add_mon_handler, handler, args, notify}} ->
         {hib, reply, handlers} = server_add_mon_handler(handler, args, handlers, notify)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:add_process_handler, pid, notify}} ->
         {hib, reply, handlers} = server_add_process_handler(pid, handlers, notify)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:delete_handler, handler, args}} ->
         {reply, handlers} = server_remove_handler(handler, args, handlers, name)
         reply(tag, reply)
         loop(parent, name, handlers, debug, false)
-
       {_from, tag, {:swap_handler, handler1, args1, handler2, args2}} ->
-        {hib, reply, handlers} =
-          server_swap_handler(handler1, args1, handler2, args2, handlers, nil, name)
-
+        {hib, reply, handlers} = server_swap_handler(handler1, args1, handler2, args2, handlers, nil, name)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, {:swap_mon_handler, handler1, args1, handler2, args2, mon}} ->
-        {hib, reply, handlers} =
-          server_swap_handler(handler1, args1, handler2, args2, handlers, mon, name)
-
+        {hib, reply, handlers} = server_swap_handler(handler1, args1, handler2, args2, handlers, mon, name)
         reply(tag, reply)
         loop(parent, name, handlers, debug, hib)
-
       {_from, tag, :which_handlers} ->
         reply(tag, server_which_handlers(handlers))
         loop(parent, name, handlers, debug, false)
-
       {_from, tag, :get_modules} ->
         reply(tag, server_get_modules(handlers))
         loop(parent, name, handlers, debug, false)
-
       other ->
         {hib, handlers} = server_info(other, handlers, name)
         loop(parent, name, handlers, debug, hib)
@@ -483,38 +426,31 @@ defmodule GenEvent do
           handler
         end
       end
-
     {:ok, [name, handlers, hib]}
   end
 
   @doc false
   def system_get_state([_name, handlers, _hib]) do
-    tuples =
-      for handler(module: mod, id: id, state: state) <- handlers do
-        {mod, id, state}
-      end
-
+    tuples = for handler(module: mod, id: id, state: state) <- handlers do
+      {mod, id, state}
+    end
     {:ok, tuples}
   end
 
   @doc false
   def system_replace_state(fun, [name, handlers, hib]) do
     {handlers, states} =
-      :lists.unzip(
-        for handler <- handlers do
-          handler(module: mod, id: id, state: state) = handler
-          cur = {mod, id, state}
-
-          try do
-            new = {^mod, ^id, new_state} = fun.(cur)
-            {handler(handler, state: new_state), new}
-          catch
-            _, _ ->
-              {handler, cur}
-          end
+      :lists.unzip(for handler <- handlers do
+        handler(module: mod, id: id, state: state) = handler
+        cur = {mod, id, state}
+        try do
+          new = {^mod, ^id, new_state} = fun.(cur)
+          {handler(handler, state: new_state), new}
+        catch
+          _, _ ->
+            {handler, cur}
         end
-      )
-
+      end)
     {:ok, states, [name, handlers, hib]}
   end
 
@@ -523,27 +459,23 @@ defmodule GenEvent do
     [pdict, sys_state, parent, _debug, [name, handlers, _hib]] = status_data
     header = :gen.format_status_header('Status for event handler', name)
 
-    formatted =
-      for handler <- handlers do
-        handler(module: module, state: state) = handler
-
-        if function_exported?(module, :format_status, 2) do
-          try do
-            state = module.format_status(opt, [pdict, state])
-            handler(handler, state: state)
-          catch
-            _, _ -> handler
-          end
-        else
-          handler
+    formatted = for handler <- handlers do
+      handler(module: module, state: state) = handler
+      if function_exported?(module, :format_status, 2) do
+        try do
+          state = module.format_status(opt, [pdict, state])
+          handler(handler, state: state)
+        catch
+          _, _ -> handler
         end
+      else
+        handler
       end
+    end
 
-    [
-      header: header,
-      data: [{'Status', sys_state}, {'Parent', parent}],
-      items: {'Installed handlers', formatted}
-    ]
+    [header: header,
+     data: [{'Status', sys_state}, {'Parent', parent}],
+     items: {'Installed handlers', formatted}]
   end
 
   ## Loop helpers
@@ -551,21 +483,16 @@ defmodule GenEvent do
   defp print_event(dev, {:in, msg}, name) do
     case msg do
       {:notify, event} ->
-        IO.puts(dev, "*DBG* #{inspect(name)} got event #{inspect(event)}")
-
+        IO.puts dev, "*DBG* #{inspect name} got event #{inspect event}"
       {_, _, {:call, handler, query}} ->
-        IO.puts(
-          dev,
-          "*DBG* #{inspect(name)} (handler #{inspect(handler)}) got call #{inspect(query)}"
-        )
-
+        IO.puts dev, "*DBG* #{inspect name} (handler #{inspect handler}) got call #{inspect query}"
       _ ->
-        IO.puts(dev, "*DBG* #{inspect(name)} got #{inspect(msg)}")
+        IO.puts dev, "*DBG* #{inspect name} got #{inspect msg}"
     end
   end
 
   defp print_event(dev, dbg, name) do
-    IO.puts(dev, "*DBG* #{inspect(name)}: #{inspect(dbg)}")
+    IO.puts dev, "*DBG* #{inspect name}: #{inspect dbg}"
   end
 
   defp server_add_handler({module, id}, args, handlers) do
@@ -592,7 +519,8 @@ defmodule GenEvent do
 
   defp server_add_process_handler(pid, handlers, notify) do
     ref = Process.monitor(pid)
-    handler = handler(module: GenEvent.Stream, id: {self(), ref}, pid: notify, ref: ref)
+    handler = handler(module: GenEvent.Stream, id: {self(), ref},
+                      pid: notify, ref: ref)
     do_add_handler(GenEvent.Stream, handler, {pid, ref}, handlers, {self(), ref})
   end
 
@@ -627,7 +555,6 @@ defmodule GenEvent do
       {pid, _ref} when is_pid(pid) ->
         server_process_notify(mode, event, handler)
         server_split_process_handlers(mode, event, t, handlers, [handler | streams])
-
       _ ->
         server_split_process_handlers(mode, event, t, [handler | handlers], streams)
     end
@@ -638,18 +565,17 @@ defmodule GenEvent do
   end
 
   defp server_process_notify(mode, event, handler(state: {pid, ref})) do
-    send(pid, {self(), {self(), ref}, {mode_to_tag(mode), event}})
+    send pid, {self(), {self(), ref}, {mode_to_tag(mode), event}}
   end
 
-  defp mode_to_tag(:ack), do: :ack_notify
-  defp mode_to_tag(:sync), do: :sync_notify
+  defp mode_to_tag(:ack),   do: :ack_notify
+  defp mode_to_tag(:sync),  do: :sync_notify
   defp mode_to_tag(:async), do: :notify
 
   defp server_notify(event, fun, [handler | t], name, handlers, acc, hib) do
     case server_update(handler, fun, event, name, handlers) do
       {new_hib, handler} ->
         server_notify(event, fun, t, name, handlers, [handler | acc], hib or new_hib)
-
       :error ->
         server_notify(event, fun, t, name, handlers, acc, hib)
     end
@@ -667,20 +593,16 @@ defmodule GenEvent do
         case res do
           {:ok, state} ->
             {false, handler(handler, state: state)}
-
           {:ok, state, :hibernate} ->
             {true, handler(handler, state: state)}
-
           :remove_handler ->
             do_terminate(handler, :remove_handler, event, name, :normal)
             :error
-
           other ->
             reason = {:bad_return_value, other}
             do_terminate(handler, {:error, reason}, event, name, reason)
             :error
         end
-
       {:error, reason} ->
         do_terminate(handler, {:error, reason}, event, name, reason)
         :error
@@ -691,19 +613,16 @@ defmodule GenEvent do
     server_collect_process_handlers(:async, event, t, [handler | handlers], name)
   end
 
-  defp server_collect_process_handlers(mode, event, [handler | t], handlers, name)
-       when mode in [:sync, :ack] do
+  defp server_collect_process_handlers(mode, event, [handler | t], handlers, name) when mode in [:sync, :ack] do
     handler(ref: ref, id: id) = handler
 
     receive do
       {^ref, :ok} ->
         server_collect_process_handlers(mode, event, t, [handler | handlers], name)
-
       {_from, tag, {:delete_handler, ^id, args}} ->
         do_terminate(handler, args, :remove, name, :normal)
         reply(tag, :ok)
         server_collect_process_handlers(mode, event, t, handlers, name)
-
       {:DOWN, ^ref, _, _, reason} ->
         do_terminate(handler, {:stop, reason}, :DOWN, name, :shutdown)
         server_collect_process_handlers(mode, event, t, handlers, name)
@@ -718,12 +637,10 @@ defmodule GenEvent do
     case :lists.keyfind(module, handler(:id) + 1, handlers) do
       false ->
         {false, {:error, :not_found}, handlers}
-
       handler ->
         case server_call_update(handler, query, name, handlers) do
           {{hib, handler}, reply} ->
             {hib, reply, :lists.keyreplace(module, handler(:id) + 1, handlers, handler)}
-
           {:error, reply} ->
             {false, reply, :lists.keydelete(module, handler(:id) + 1, handlers)}
         end
@@ -732,26 +649,21 @@ defmodule GenEvent do
 
   defp server_call_update(handler, query, name, _handlers) do
     handler(module: module, state: state) = handler
-
     case do_handler(module, :handle_call, [query, state]) do
       {:ok, res} ->
         case res do
           {:ok, reply, state} ->
             {{false, handler(handler, state: state)}, reply}
-
           {:ok, reply, state, :hibernate} ->
             {{true, handler(handler, state: state)}, reply}
-
           {:remove_handler, reply} ->
             do_terminate(handler, :remove_handler, query, name, :normal)
             {:error, reply}
-
           other ->
             reason = {:bad_return_value, other}
             do_terminate(handler, {:error, reason}, query, name, reason)
             {:error, {:error, reason}}
         end
-
       {:error, reason} ->
         do_terminate(handler, {:error, reason}, query, name, reason)
         {:error, {:error, reason}}
@@ -759,9 +671,9 @@ defmodule GenEvent do
   end
 
   defp server_get_modules(handlers) do
-    for(handler(module: module) <- handlers, do: module)
-    |> :ordsets.from_list()
-    |> :ordsets.to_list()
+    (for handler(module: module) <- handlers, do: module)
+    |> :ordsets.from_list
+    |> :ordsets.to_list
   end
 
   defp server_which_handlers(handlers) do
@@ -773,19 +685,16 @@ defmodule GenEvent do
       for handler <- handlers do
         do_terminate(handler, :stop, :stop, name, :shutdown)
       end
-
     exit(reason)
   end
 
   defp reply({from, ref}, msg) do
-    send(from, {ref, msg})
+    send from, {ref, msg}
   end
 
   defp handle_down(ref, reason, handlers, name) do
     case :lists.keyfind(ref, handler(:ref) + 1, handlers) do
-      false ->
-        :error
-
+      false -> :error
       handler ->
         do_terminate(handler, {:stop, reason}, :DOWN, name, :shutdown)
         {:ok, :lists.keydelete(ref, handler(:ref) + 1, handlers)}
@@ -800,21 +709,16 @@ defmodule GenEvent do
             case res do
               {:ok, state} ->
                 {false, succ, [handler(handler, state: state) | handlers]}
-
               {:ok, state, :hibernate} ->
                 {true, succ, [handler(handler, state: state) | handlers]}
-
               {:error, _} = error ->
                 {false, error, handlers}
-
               other ->
                 {false, {:error, {:bad_return_value, other}}, handlers}
             end
-
           {:error, _} = error ->
             {false, error, handlers}
         end
-
       _ ->
         {false, {:error, :already_present}, handlers}
     end
@@ -824,7 +728,6 @@ defmodule GenEvent do
     case :lists.keytake(module, handler(:id) + 1, handlers) do
       {:value, handler, handlers} ->
         {do_terminate(handler, args, last_in, name, reason), handlers}
-
       false ->
         {{:error, :not_found}, handlers}
     end
@@ -838,7 +741,6 @@ defmodule GenEvent do
         {:ok, res} -> res
         {:error, _} = error -> error
       end
-
     report_terminate(handler, reason, state, last_in, name)
     res
   end
@@ -848,8 +750,8 @@ defmodule GenEvent do
       apply(mod, fun, args)
     catch
       :throw, val -> {:ok, val}
-      :error, val -> {:error, {val, __STACKTRACE__}}
-      :exit, val -> {:error, val}
+      :error, val -> {:error, {val, System.stacktrace}}
+      :exit, val  -> {:error, val}
     else
       res -> {:ok, res}
     end
@@ -857,35 +759,29 @@ defmodule GenEvent do
 
   defp report_terminate(handler, reason, state, last_in, name) do
     report_error(handler, reason, state, last_in, name)
-
     if ref = handler(handler, :ref) do
       Process.demonitor(ref, [:flush])
     end
-
     if pid = handler(handler, :pid) do
-      send(pid, {:gen_event_EXIT, handler(handler, :id), reason})
+      send pid, {:gen_event_EXIT, handler(handler, :id), reason}
     end
   end
 
   defp report_error(_handler, :normal, _, _, _), do: :ok
   defp report_error(_handler, :shutdown, _, _, _), do: :ok
   defp report_error(_handler, {:swapped, _, _}, _, _, _), do: :ok
-
   defp report_error(handler, reason, state, last_in, name) do
     reason =
       case reason do
         {:undef, [{m, f, a, _} | _] = mfas} ->
           cond do
-            :code.is_loaded(m) == false ->
+            :code.is_loaded(m) === false ->
               {:"module could not be loaded", mfas}
-
             function_exported?(m, f, length(a)) ->
               reason
-
             true ->
               {:"function not exported", mfas}
           end
-
         _ ->
           reason
       end
@@ -894,10 +790,10 @@ defmodule GenEvent do
 
     :error_logger.error_msg(
       '** gen_event handler ~p crashed.~n' ++
-        '** Was installed in ~p~n' ++
-        '** Last event was: ~p~n' ++ '** When handler state == ~p~n' ++ '** Reason == ~p~n',
-      [handler(handler, :id), name, last_in, formatted, reason]
-    )
+      '** Was installed in ~p~n' ++
+      '** Last event was: ~p~n' ++
+      '** When handler state == ~p~n' ++
+      '** Reason == ~p~n', [handler(handler, :id), name, last_in, formatted, reason])
   end
 
   defp report_status(handler(module: module), state) do

lib/elixir/lib/gen_event/stream.ex

@@ -2,7 +2,9 @@ defmodule GenEvent.Stream do
   @moduledoc false
   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
@@ -22,7 +24,6 @@ defmodule GenEvent.Stream do
   def handle_call(msg, _state) do
     # 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 +48,7 @@ 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 +62,26 @@ 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 +129,6 @@ 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
@@ -153,7 +146,6 @@ 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 +153,7 @@ 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

lib/elixir/lib/hash_dict.ex

@@ -1,13 +1,12 @@
 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
+  # (hard-deprecated in elixir_dispatch)
 
   use Dict
 
@@ -24,70 +23,58 @@ 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 +84,7 @@ 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 +92,26 @@ 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, {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 +120,16 @@ 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, {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}
@@ -162,35 +138,28 @@ defmodule HashDict do
 
   defp do_delete(node, key, hash) do
     index = key_mask(hash)
-
     case elem(node, index) do
       [] ->
         :error
-
       [^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}
-
           {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] ->
@@ -198,12 +167,11 @@ defmodule HashDict do
             @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
 
@@ -228,12 +196,7 @@ 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
@@ -279,24 +242,17 @@ defimpl Enumerable, for: HashDict do
     module = HashDict
     {:ok, module.size(dict)}
   end
-
-  def slice(_dict) do
-    {:error, __MODULE__}
-  end
 end
 
 defimpl Collectable, for: HashDict do
   def into(original) do
     # Avoid warnings about HashDict being deprecated.
     module = HashDict
-
-    collector_fun = fn
+    {original, fn
       dict, {:cont, {key, value}} -> module.put(dict, key, value)
       dict, :done -> dict
       _, :halt -> :ok
-    end
-
-    {original, collector_fun}
+    end}
   end
 end
 
@@ -306,6 +262,6 @@ defimpl Inspect, for: HashDict do
   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(module.to_list(dict), opts), ">"]
   end
 end

lib/elixir/lib/hash_set.ex

@@ -1,19 +1,18 @@
 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"
+  # TODO: Remove by 2.0
+  # (hard-deprecated in elixir_dispatch)
 
   @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 +21,71 @@ 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 +93,11 @@ 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
@@ -128,29 +112,24 @@ defmodule HashSet do
 
   defp do_member?(node, term, hash) do
     index = key_mask(hash)
-
     case elem(node, index) do
-      [] -> false
+      []          -> false
       [^term | _] -> true
-      [_] -> false
-      [_ | n] -> do_member?(n, term, key_shift(hash))
+      [_]         -> 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 | _] ->
         {node, 0}
-
       [t] ->
         n = put_elem(@node_template, key_mask(key_shift(hash)), [term])
         {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}
@@ -159,35 +138,28 @@ defmodule HashSet do
 
   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] ->
         {:ok, put_elem(node, index, do_compact_node(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])}
-
           :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] ->
@@ -195,17 +167,16 @@ defmodule HashSet do
             @node_template -> [t]
             n -> [t | n]
           end
-
         [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([], 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
@@ -240,12 +211,7 @@ defmodule HashSet 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
@@ -287,24 +253,17 @@ defimpl Enumerable, for: HashSet do
     module = HashSet
     {:ok, module.size(set)}
   end
-
-  def slice(_set) do
-    {:error, __MODULE__}
-  end
 end
 
 defimpl Collectable, for: HashSet do
   def into(original) do
     # Avoid warnings about HashSet being deprecated.
     module = HashSet
-
-    collector_fun = fn
+    {original, fn
       set, {:cont, term} -> module.put(set, term)
       set, :done -> set
       _, :halt -> :ok
-    end
-
-    {original, collector_fun}
+    end}
   end
 end
 
@@ -314,6 +273,6 @@ defimpl Inspect, for: HashSet do
   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(module.to_list(set), opts), ">"]
   end
 end

lib/elixir/lib/inspect.ex

@@ -1,33 +1,29 @@
 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
 
   Many times, inspecting a structure can be implemented in function
-  of existing entities. For example, here is `MapSet`'s `inspect/2`
+  of existing entities. For example, here is `MapSet`'s `inspect`
   implementation:
 
       defimpl Inspect, for: MapSet 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
 
@@ -39,8 +35,8 @@ defprotocol Inspect do
   other string `">"`.
 
   Since regular strings are valid entities in an algebra document,
-  an implementation of the `Inspect` protocol may simply return a
-  string, although that will devoid it of any pretty-printing.
+  an implementation of inspect may simply return a string,
+  although that will devoid it of any pretty-printing.
 
   ## Error handling
 
@@ -48,29 +44,11 @@ defprotocol Inspect do
   Elixir will raise an `ArgumentError` error and will automatically fall back
   to a raw representation for printing the structure.
 
-  You can however access the underlying error by invoking the `Inspect`
-  implementation directly. For example, to test `Inspect.MapSet` above,
+  You can however access the underlying error by invoking the Inspect
+  implementation directly. For example, to test Inspect.MapSet above,
   you can invoke it as:
 
-      Inspect.MapSet.inspect(MapSet.new(), %Inspect.Opts{})
-
-  ## Deriving
-
-  The `Inspect` protocol can be derived to hide certain fields from
-  structs, so they don't show up in logs, inspects and similar. This
-  is especially useful for fields containing private information.
-
-  The options `:only` and `:except` can be used with `@derive` to
-  specify which fields should and should not appear in the
-  algebra document:
-
-      defmodule User do
-        @derive {Inspect, only: [:id, :name]}
-        defstruct [:id, :name, :address]
-      end
-
-      inspect(%User{id: 1, name: "Homer", address: "742 Evergreen Terrace"})
-      #=> #User<id: 1, name: "Homer", ...>
+      Inspect.MapSet.inspect(MapSet.new, %Inspect.Opts{})
 
   """
 
@@ -84,12 +62,37 @@ defimpl Inspect, for: Atom do
   require Macro
 
   def inspect(atom, opts) do
-    color(Identifier.inspect_as_atom(atom), color_key(atom), opts)
+    color(inspect(atom), color_key(atom), opts)
   end
 
   defp color_key(atom) when is_boolean(atom), do: :boolean
-  defp color_key(nil), do: nil
+  defp color_key(nil), do: :nil
   defp color_key(_), do: :atom
+
+  def inspect(atom) when is_nil(atom) or is_boolean(atom) do
+    Atom.to_string(atom)
+  end
+
+  def inspect(atom) when is_atom(atom) do
+    binary = Atom.to_string(atom)
+
+    case Macro.classify_identifier(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, :not_callable] ->
+        ":" <> binary
+      :other ->
+        {escaped, _} = Inspect.BitString.escape(binary, ?")
+        IO.iodata_to_binary [?:, ?", escaped, ?"]
+    end
+  end
 end
 
 defimpl Inspect, for: BitString do
@@ -97,13 +100,12 @@ defimpl Inspect, for: BitString do
     %Inspect.Opts{binaries: bins, base: base, printable_limit: printable_limit} = opts
 
     if base == :decimal and
-         (bins == :as_strings or (bins == :infer and String.printable?(term, printable_limit))) do
+       (bins == :as_strings or (bins == :infer and String.printable?(term, printable_limit))) do
       inspected =
-        case Identifier.escape(term, ?", printable_limit) do
+        case escape(term, ?", printable_limit) do
           {escaped, ""} -> [?", escaped, ?"]
           {escaped, _} -> [?", escaped, ?", " <> ..."]
         end
-
       color(IO.iodata_to_binary(inspected), :string, opts)
     else
       inspect_bitstring(term, opts)
@@ -114,6 +116,98 @@ defimpl Inspect, for: BitString do
     inspect_bitstring(term, opts)
   end
 
+  ## Escaping
+
+  @doc false
+  def escape(other, char) do
+    escape(other, char, :infinity, [])
+  end
+
+  @doc false
+  def escape(other, char, count) do
+    escape(other, char, count, [])
+  end
+
+  defp escape(<<_, _::binary>> = binary, _char, 0, acc) do
+    {acc, binary}
+  end
+  defp escape(<<char, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | [?\\, char]])
+  end
+  defp escape(<<?#, ?{, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\\#{'])
+  end
+  defp escape(<<?\a, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\a'])
+  end
+  defp escape(<<?\b, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\b'])
+  end
+  defp escape(<<?\d, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\d'])
+  end
+  defp escape(<<?\e, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\e'])
+  end
+  defp escape(<<?\f, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\f'])
+  end
+  defp escape(<<?\n, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\n'])
+  end
+  defp escape(<<?\r, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\r'])
+  end
+  defp escape(<<?\\, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\\\'])
+  end
+  defp escape(<<?\t, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\t'])
+  end
+  defp escape(<<?\v, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | '\\v'])
+  end
+  defp escape(<<h::utf8, t::binary>>, char, count, acc)
+       when h in 0x20..0x7E
+       when h in 0xA0..0xD7FF
+       when h in 0xE000..0xFFFD
+       when h in 0x10000..0x10FFFF do
+    escape(t, char, decrement(count), [acc | <<h::utf8>>])
+  end
+  defp escape(<<h, t::binary>>, char, count, acc) do
+    escape(t, char, decrement(count), [acc | escape_char(h)])
+  end
+  defp escape(<<>>, _char, _count, acc) do
+    {acc, <<>>}
+  end
+
+  @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
+
+  ## Bitstrings
+
   defp inspect_bitstring("", opts) do
     color("<<>>", :binary, opts)
   end
@@ -121,8 +215,7 @@ defimpl Inspect, for: BitString do
   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))
+    nest surround(left, each_bit(bitstring, opts.limit, opts), right), 1
   end
 
   defp each_bit(_, 0, _) do
@@ -138,10 +231,8 @@ defimpl Inspect, for: BitString do
   end
 
   defp each_bit(<<h, t::bitstring>>, counter, opts) do
-    flex_glue(
-      concat(Inspect.Integer.inspect(h, opts), ","),
-      each_bit(t, decrement(counter), opts)
-    )
+    glue(concat(Inspect.Integer.inspect(h, opts), ","),
+         each_bit(t, decrement(counter), opts))
   end
 
   defp each_bit(bitstring, _counter, opts) do
@@ -152,7 +243,7 @@ defimpl Inspect, for: BitString do
 
   @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
@@ -162,26 +253,17 @@ defimpl Inspect, for: List do
 
   # 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
-
+    %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"
-            )
-
+            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")
+            IO.warn "the :char_lists inspect option is deprecated, use :charlists instead"
             lists_deprecated
         end
       else
@@ -193,27 +275,24 @@ defimpl Inspect, for: List do
     close = color("]", :list, opts)
 
     cond do
-      lists == :as_charlists or (lists == :infer and List.ascii_printable?(term, printable_limit)) ->
+      lists == :as_charlists or (lists == :infer and printable?(term, printable_limit)) ->
         inspected =
-          case Identifier.escape(IO.chardata_to_string(term), ?', printable_limit) do
+          case Inspect.BitString.escape(IO.chardata_to_string(term), ?', printable_limit) do
             {escaped, ""} -> [?', escaped, ?']
             {escaped, _} -> [?', escaped, ?', " ++ ..."]
           end
-
-        IO.iodata_to_binary(inspected)
-
+        IO.iodata_to_binary inspected
       keyword?(term) ->
-        container_doc(open, term, close, opts, &keyword/2, separator: sep, break: :strict)
-
+        surround_many(open, term, close, opts, &keyword/2, sep)
       true ->
-        container_doc(open, term, close, opts, &to_doc/2, separator: sep)
+        surround_many(open, term, close, opts, &to_doc/2, sep)
     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)))
+    key = color(key_to_binary(key) <> ": ", :atom, opts)
+    concat(key, to_doc(value, opts))
   end
 
   @doc false
@@ -224,8 +303,38 @@ defimpl Inspect, for: List do
     end
   end
 
-  def keyword?([]), do: true
+  def keyword?([]),     do: true
   def keyword?(_other), do: false
+
+  @doc false
+  def printable?(list), do: printable?(list, :infinity)
+
+  @doc false
+  def printable?(_, 0), do: true
+  def printable?([char | rest], counter) when char in 32..126, do: printable?(rest, decrement(counter))
+  def printable?([?\n | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\r | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\t | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\v | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\b | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\f | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\e | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([?\a | rest], counter), do: printable?(rest, decrement(counter))
+  def printable?([], _counter), do: true
+  def printable?(_, _counter), do: false
+
+  @compile {:inline, decrement: 1}
+  defp decrement(:infinity), do: :infinity
+  defp decrement(counter),   do: counter - 1
+
+  ## 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
@@ -233,14 +342,13 @@ defimpl Inspect, for: Tuple 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(open, Tuple.to_list(tuple), close, opts, &to_doc/2, sep)
   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
@@ -248,7 +356,7 @@ defimpl Inspect, for: Map do
     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(open, map, close, opts, traverse_fun(map, opts), sep)
   end
 
   defp traverse_fun(list, opts) do
@@ -261,7 +369,10 @@ defimpl Inspect, for: Map do
   end
 
   defp to_map({key, value}, opts, sep) do
-    concat(concat(to_doc(key, opts), sep), to_doc(value, opts))
+    concat(
+      concat(to_doc(key, opts), sep),
+      to_doc(value, opts)
+    )
   end
 end
 
@@ -273,27 +384,20 @@ defimpl Inspect, for: Integer do
 
   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
@@ -307,48 +411,110 @@ 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])
+    source = IO.iodata_to_binary(['~r/', escape(regex.source, ?/), ?/, regex.opts])
     color(source, :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::binary>>, buf, term),
+    do: escape(rest, [buf | [?\\, term]], term)
+
+  # The list of characters is from 'String.printable?' implementation
+  # minus characters treated specially by regex: \s, \d, \b, \e
+
+  defp escape(<<?\n, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\n'], term)
+
+  defp escape(<<?\r, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\r'], term)
+
+  defp escape(<<?\t, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\t'], term)
+
+  defp escape(<<?\v, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\v'], term)
+
+  defp escape(<<?\f, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\f'], term)
+
+  defp escape(<<?\a, rest::binary>>, buf, term),
+    do: escape(rest, [buf | '\\a'], term)
+
+  defp escape(<<char::utf8, rest::binary>>, buf, term)
+       when char in 0x20..0x7E
+       when char in 0xA0..0xD7FF
+       when char in 0xE000..0xFFFD
+       when char in 0x10000..0x10FFFF,
+    do: escape(rest, [buf | <<char::utf8>>], term)
+
+  defp escape(<<char, rest::binary>>, buf, term),
+    do: escape(rest, [buf | Inspect.BitString.escape_char(char)], 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)}.#{escape_name(name)}/#{fun_info[:arity]}"
+    else
+      case Atom.to_charlist(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
 
+  def escape_name(atom) when is_atom(atom) do
+    string = Atom.to_string(atom)
+
+    case Macro.classify_identifier(atom) do
+      :callable ->
+        string
+      type when type in [:not_callable, :alias] ->
+        "\"" <> string <> "\""
+      :other ->
+        {escaped, _} = Inspect.BitString.escape(string, ?")
+        IO.iodata_to_binary [?", escaped, ?"]
+    end
+  end
+
+  # Example of this format: -NAME/ARITY-fun-COUNT-
+  def extract_anonymous_fun_parent(atom) when is_atom(atom) do
+    extract_anonymous_fun_parent(Atom.to_string(atom))
+  end
+
+  def extract_anonymous_fun_parent("-" <> rest) do
+    [trailing | reversed] =
+      rest
+      |> String.split("/")
+      |> Enum.reverse()
+
+    case String.split(trailing, "-") do
+      [arity, _inner, _count, ""] ->
+        {reversed |> Enum.reverse |> Enum.join("/") |> String.to_atom(), arity}
+      _other ->
+        :error
+    end
+  end
+
+  def extract_anonymous_fun_parent(other) when is_binary(other), do: :error
+
   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
@@ -356,17 +522,17 @@ defimpl Inspect, for: Function do
   end
 
   defp extract_name(name) do
-    case Identifier.extract_anonymous_fun_parent(name) do
+    case extract_anonymous_fun_parent(name) do
       {name, arity} ->
-        "." <> Identifier.inspect_as_function(name) <> "/" <> arity
-
+        "." <> escape_name(name) <> "/" <> arity
       :error ->
-        "." <> Identifier.inspect_as_function(name)
+        "." <> escape_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
 
@@ -390,66 +556,20 @@ defimpl Inspect, for: Reference do
 end
 
 defimpl Inspect, for: Any do
-  defmacro __deriving__(module, struct, options) do
-    fields =
-      struct
-      |> Map.drop([:__exception__, :__struct__])
-      |> Map.keys()
-
-    only = Keyword.get(options, :only, fields)
-    except = Keyword.get(options, :except, [])
-
-    filtered_fields =
-      fields
-      |> Enum.reject(&(&1 in except))
-      |> Enum.filter(&(&1 in only))
-
-    inspect_module =
-      if fields == only and except == [] do
-        quote(do: Inspect.Map)
-      else
-        quote(do: Inspect.Any)
-      end
-
-    quote do
-      defimpl Inspect, for: unquote(module) do
-        def inspect(struct, opts) do
-          map = Map.take(struct, unquote(filtered_fields))
-          colorless_opts = %{opts | syntax_colors: []}
-          name = Inspect.Atom.inspect(unquote(module), colorless_opts)
-          unquote(inspect_module).inspect(map, name, opts)
-        end
-      end
-    end
-  end
-
-  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))
+        if :maps.keys(dunder) == :maps.keys(map) do
+          pruned = :maps.remove(:__exception__, :maps.remove(:__struct__, map))
           colorless_opts = %{opts | syntax_colors: []}
-          Inspect.Map.inspect(pruned, Inspect.Atom.inspect(module, colorless_opts), opts)
+          Inspect.Map.inspect(pruned, Inspect.Atom.inspect(struct, colorless_opts), opts)
         else
-          Inspect.Map.inspect(struct, opts)
+          Inspect.Map.inspect(map, opts)
         end
     end
   end
-
-  def inspect(map, name, opts) do
-    # Use the :limit option and an extra element to force
-    # `container_doc/6` to append "...".
-    opts = %{opts | limit: min(opts.limit, map_size(map))}
-    map = :maps.to_list(map) ++ ["..."]
-
-    open = color("#" <> name <> "<", :map, opts)
-    sep = color(",", :map, opts)
-    close = color(">", :map, opts)
-
-    container_doc(open, map, close, opts, &Inspect.List.keyword/2, separator: sep, break: :strict)
-  end
 end

lib/elixir/lib/integer.ex

@@ -1,15 +1,6 @@
 defmodule Integer do
   @moduledoc """
   Functions for working with integers.
-
-  Some functions that work on integers are found in `Kernel`:
-
-    * `abs/1`
-    * `div/2`
-    * `max/2`
-    * `min/2`
-    * `rem/2`
-
   """
 
   import Bitwise
@@ -37,7 +28,9 @@ defmodule Integer do
       false
 
   """
-  defguard is_odd(integer) when is_integer(integer) and (integer &&& 1) == 1
+  defmacro is_odd(integer) do
+    quote do: (unquote(integer) &&& 1) == 1
+  end
 
   @doc """
   Determines if an `integer` is even.
@@ -62,7 +55,9 @@ defmodule Integer do
       true
 
   """
-  defguard is_even(integer) when is_integer(integer) and (integer &&& 1) == 0
+  defmacro is_even(integer) do
+    quote do: (unquote(integer) &&& 1) == 0
+  end
 
   @doc """
   Computes the modulo remainder of an integer division.
@@ -81,11 +76,9 @@ defmodule Integer do
       -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
@@ -115,10 +108,9 @@ defmodule Integer do
       -50
 
   """
-  @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
+    if (dividend * divisor < 0) and rem(dividend, divisor) != 0 do
       div(dividend, divisor) - 1
     else
       div(dividend, divisor)
@@ -149,8 +141,14 @@ defmodule Integer do
     do_digits(integer, base, [])
   end
 
-  defp do_digits(integer, base, acc) when abs(integer) < base, do: [integer | acc]
-
+  defp do_digits(digit, base, []) when abs(digit) < base,
+    do: [digit]
+  defp do_digits(digit, base, []) when digit == -base,
+    do: [-1, 0]
+  defp do_digits(base, base, []),
+    do: [1, 0]
+  defp do_digits(0, _base, acc),
+    do: acc
   defp do_digits(integer, base, acc),
     do: do_digits(div(integer, base), base, [rem(integer, base) | acc])
 
@@ -158,7 +156,7 @@ defmodule Integer do
   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 than or equal to `2`.
+  This one can be an integer >= 2.
 
   ## Examples
 
@@ -172,16 +170,24 @@ defmodule Integer do
       0
 
   """
-  @spec undigits([integer], pos_integer) :: integer
+  @spec undigits([integer], integer) :: integer
   def undigits(digits, base \\ 10) when is_list(digits) and is_integer(base) and base >= 2 do
     do_undigits(digits, base, 0)
   end
 
-  defp do_undigits([], _base, acc), do: acc
+  defp do_undigits([], _base, 0),
+    do: 0
+  defp do_undigits([digit], base, 0) when is_integer(digit) and digit < base,
+    do: digit
+  defp do_undigits([1, 0], base, 0),
+    do: base
+  defp do_undigits([0 | tail], base, 0),
+    do: do_undigits(tail, base, 0)
 
+  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}")
-
+    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)
 
@@ -196,7 +202,7 @@ defmodule Integer do
 
   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,
+  If you want to convert a string-formatted integer directly to a integer,
   `String.to_integer/1` or `String.to_integer/2` can be used instead.
 
   ## Examples
@@ -229,15 +235,14 @@ defmodule Integer do
   @spec parse(binary, 2..36) :: {integer, binary} | :error
   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 not base in 2..36 do
+    raise ArgumentError, "invalid base #{inspect base}"
   end
 
   def parse(binary, base) do
     case count_digits(binary, base) do
       0 ->
         :error
-
       count ->
         {digits, rem} = :erlang.split_binary(binary, count)
         {:erlang.binary_to_integer(digits, base), rem}
@@ -257,12 +262,11 @@ defmodule Integer do
 
   digits = [{?0..?9, -?0}, {?A..?Z, 10 - ?A}, {?a..?z, 10 - ?a}]
 
-  for {chars, diff} <- digits,
-      char <- chars do
+  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
+        when base > unquote(digit) do
       count_digits_nosign(rest, base, count + 1)
     end
   end
@@ -290,7 +294,7 @@ defmodule Integer do
       "123"
 
   """
-  @spec to_string(integer) :: String.t()
+  @spec to_string(integer) :: String.t
   def to_string(integer) do
     :erlang.integer_to_binary(integer)
   end
@@ -311,11 +315,11 @@ defmodule Integer do
       iex> Integer.to_string(-100, 16)
       "-64"
 
-      iex> Integer.to_string(882_681_651, 36)
+      iex> Integer.to_string(882681651, 36)
       "ELIXIR"
 
   """
-  @spec to_string(integer, 2..36) :: String.t()
+  @spec to_string(integer, 2..36) :: String.t
   def to_string(integer, base) do
     :erlang.integer_to_binary(integer, base)
   end
@@ -360,7 +364,7 @@ defmodule Integer do
       iex> Integer.to_charlist(-100, 16)
       '-64'
 
-      iex> Integer.to_charlist(882_681_651, 36)
+      iex> Integer.to_charlist(882681651, 36)
       'ELIXIR'
 
   """
@@ -398,7 +402,6 @@ defmodule Integer do
       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
@@ -410,12 +413,14 @@ defmodule Integer do
   defp gcd_positive(integer1, integer2), do: gcd_positive(integer2, rem(integer1, integer2))
 
   # TODO: Remove by 2.0
+  # (hard-deprecated in elixir_dispatch)
   @doc false
-  @deprecated "Use Integer.to_charlist/1 instead"
+  @spec to_char_list(integer) :: charlist
   def to_char_list(integer), do: Integer.to_charlist(integer)
 
   # TODO: Remove by 2.0
+  # (hard-deprecated in elixir_dispatch)
   @doc false
-  @deprecated "Use Integer.to_charlist/2 instead"
+  @spec to_char_list(integer, 2..36) :: charlist
   def to_char_list(integer, base), do: Integer.to_charlist(integer, base)
 end

lib/elixir/lib/io.ex

@@ -27,16 +27,16 @@ 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.
 
   """
 
   @type device :: atom | pid
   @type nodata :: {:error, term} | :eof
-  @type chardata :: String.t() | maybe_improper_list(char | chardata, String.t() | [])
+  @type chardata() :: :unicode.chardata()
 
   defmacrop is_iodata(data) do
     quote do
@@ -143,20 +143,21 @@ defmodule IO do
   @doc """
   Writes `item` to the given `device`.
 
-  By default, the `device` is the standard output.
+  By default the `device` is the standard output.
+  It returns `:ok` if it succeeds.
 
   ## Examples
 
-      IO.write("sample")
+      IO.write "sample"
       #=> sample
 
-      IO.write(:stderr, "error")
+      IO.write :stderr, "error"
       #=> error
 
   """
-  @spec write(device, chardata | String.Chars.t()) :: :ok
+  @spec write(device, chardata | String.Chars.t) :: :ok
   def write(device \\ :stdio, item) do
-    :io.put_chars(map_dev(device), to_chardata(item))
+    :io.put_chars map_dev(device), to_chardata(item)
   end
 
   @doc """
@@ -171,28 +172,16 @@ defmodule IO do
   """
   @spec binwrite(device, iodata) :: :ok | {:error, term}
   def binwrite(device \\ :stdio, item) when is_iodata(item) do
-    :file.write(map_dev(device), item)
+    :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
+  @spec puts(device, chardata | String.Chars.t) :: :ok
   def puts(device \\ :stdio, item) do
-    :io.put_chars(map_dev(device), [to_chardata(item), ?\n])
+    :io.put_chars map_dev(device), [to_chardata(item), ?\n]
   end
 
   @doc """
@@ -207,22 +196,18 @@ defmodule IO do
   ## Examples
 
       stacktrace = [{MyApp, :main, 1, [file: 'my_app.ex', line: 4]}]
-      IO.warn("variable bar is unused", stacktrace)
+      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
+  @spec warn(chardata | String.Chars.t, Exception.stacktrace) :: :ok
   def warn(message, []) do
-    :elixir_errors.bare_warn(nil, nil, [to_chardata(message), ?\n])
+    :elixir_errors.warn([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)
+  def warn(message, stacktrace) when is_list(stacktrace) do
+    formatted = Enum.map_join(stacktrace, "\n  ", &Exception.format_stacktrace_entry(&1))
+    :elixir_errors.warn([to_chardata(message), ?\n, "  ", formatted, ?\n])
   end
 
   @doc """
@@ -232,12 +217,12 @@ defmodule IO do
 
   ## Examples
 
-      IO.warn("variable bar is unused")
+      IO.warn "variable bar is unused"
       #=> warning: variable bar is unused
       #=>   (iex) evaluator.ex:108: IEx.Evaluator.eval/4
 
   """
-  @spec warn(chardata | String.Chars.t()) :: :ok
+  @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))
@@ -263,7 +248,7 @@ defmodule IO do
 
   ## Examples
 
-      IO.inspect(<<0, 1, 2>>, width: 40)
+      IO.inspect <<0, 1, 2>>, width: 40
 
   Prints:
 
@@ -271,7 +256,7 @@ defmodule IO do
 
   We can use the `:label` option to decorate the output:
 
-      IO.inspect(1..100, label: "a wonderful range")
+      IO.inspect 1..100, label: "a wonderful range"
 
   Prints:
 
@@ -283,7 +268,7 @@ defmodule IO do
       |> IO.inspect(label: "before")
       |> Enum.map(&(&1 * 2))
       |> IO.inspect(label: "after")
-      |> Enum.sum()
+      |> Enum.sum
 
   Prints:
 
@@ -293,7 +278,7 @@ defmodule IO do
   """
   @spec inspect(item, keyword) :: item when item: var
   def inspect(item, opts \\ []) do
-    inspect(:stdio, item, opts)
+    inspect :stdio, item, opts
   end
 
   @doc """
@@ -303,11 +288,10 @@ defmodule IO do
   """
   @spec inspect(device, item, keyword) :: 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])
+    label    = if (label = opts[:label]), do: [to_chardata(label), ": "], else: []
+    opts     = struct(Inspect.Opts, opts)
+    chardata = Inspect.Algebra.format(Inspect.Algebra.to_doc(item, opts), opts.width)
+    puts device, [label, chardata]
     item
   end
 
@@ -321,8 +305,8 @@ defmodule IO do
   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
+  @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
@@ -351,7 +335,7 @@ defmodule IO do
       NFS volume
 
   """
-  @spec getn(device, chardata | String.Chars.t(), pos_integer) :: chardata | nodata
+  @spec getn(device, chardata | String.Chars.t, pos_integer) :: chardata | nodata
   def getn(device, prompt, count) when is_integer(count) and count > 0 do
     :io.get_chars(map_dev(device), to_chardata(prompt), count)
   end
@@ -374,10 +358,10 @@ 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?\n"
 
   """
-  @spec gets(device, chardata | String.Chars.t()) :: chardata | nodata
+  @spec gets(device, chardata | String.Chars.t) :: chardata | nodata
   def gets(device \\ :stdio, prompt) do
     :io.get_line(map_dev(device), to_chardata(prompt))
   end
@@ -403,10 +387,10 @@ defmodule IO do
   Here is an example on how we mimic an echo server
   from the command line:
 
-      Enum.each(IO.stream(:stdio, :line), &IO.write(&1))
+      Enum.each IO.stream(:stdio, :line), &IO.write(&1)
 
   """
-  @spec stream(device, :line | pos_integer) :: Enumerable.t()
+  @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
@@ -431,7 +415,7 @@ defmodule IO do
   mode as it will return the wrong result.
 
   """
-  @spec binstream(device, :line | pos_integer) :: Enumerable.t()
+  @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
@@ -457,7 +441,7 @@ defmodule IO do
       "string"
 
   """
-  @spec chardata_to_string(chardata) :: String.t()
+  @spec chardata_to_string(chardata) :: String.t | no_return
   def chardata_to_string(string) when is_binary(string) do
     string
   end
@@ -519,10 +503,8 @@ defmodule IO do
     case read(device, line_or_codepoints) do
       :eof ->
         {:halt, device}
-
       {:error, reason} ->
         raise IO.StreamError, reason: reason
-
       data ->
         {[data], device}
     end
@@ -533,10 +515,8 @@ defmodule IO do
     case binread(device, line_or_chars) do
       :eof ->
         {:halt, device}
-
       {:error, reason} ->
         raise IO.StreamError, reason: reason
-
       data ->
         {[data], device}
     end
@@ -545,7 +525,7 @@ 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
+  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
 

lib/elixir/lib/io/ansi.ex

@@ -26,8 +26,7 @@ defmodule IO.ANSI do
   import IO.ANSI.Sequence
 
   @type ansicode :: atom
-  @type ansilist ::
-          maybe_improper_list(char | ansicode | binary | ansilist, binary | ansicode | [])
+  @type ansilist :: maybe_improper_list(char | ansicode | binary | ansilist, binary | ansicode | [])
   @type ansidata :: ansilist | ansicode | binary
 
   @doc """
@@ -44,7 +43,7 @@ defmodule IO.ANSI do
   end
 
   @doc "Sets foreground color."
-  @spec color(0..255) :: String.t()
+  @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()
+  @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 +65,118 @@ 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)
+  defsequence :reset, 0
 
   @doc "Bright (increased intensity) or bold."
-  defsequence(:bright, 1)
+  defsequence :bright, 1
 
   @doc "Faint (decreased intensity). Not widely supported."
-  defsequence(:faint, 2)
+  defsequence :faint, 2
 
   @doc "Italic: on. Not widely supported. Sometimes treated as inverse."
-  defsequence(:italic, 3)
+  defsequence :italic, 3
 
   @doc "Underline: single."
-  defsequence(:underline, 4)
+  defsequence :underline, 4
 
   @doc "Blink: slow. Less than 150 per minute."
-  defsequence(:blink_slow, 5)
+  defsequence :blink_slow, 5
 
   @doc "Blink: rapid. MS-DOS ANSI.SYS; 150 per minute or more; not widely supported."
-  defsequence(:blink_rapid, 6)
+  defsequence :blink_rapid, 6
 
   @doc "Image: negative. Swap foreground and background."
-  defsequence(:inverse, 7)
+  defsequence :inverse, 7
 
   @doc "Image: negative. Swap foreground and background."
-  defsequence(:reverse, 7)
+  defsequence :reverse, 7
 
   @doc "Conceal. Not widely supported."
-  defsequence(:conceal, 8)
+  defsequence :conceal, 8
 
   @doc "Crossed-out. Characters legible, but marked for deletion. Not widely supported."
-  defsequence(:crossed_out, 9)
+  defsequence :crossed_out, 9
 
   @doc "Sets primary (default) font."
-  defsequence(:primary_font, 10)
+  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)
+    defsequence :"font_#{font_n}", font_n + 10
   end
 
   @doc "Normal color or intensity."
-  defsequence(:normal, 22)
+  defsequence :normal, 22
 
   @doc "Not italic."
-  defsequence(:not_italic, 23)
+  defsequence :not_italic, 23
 
   @doc "Underline: none."
-  defsequence(:no_underline, 24)
+  defsequence :no_underline, 24
 
   @doc "Blink: off."
-  defsequence(:blink_off, 25)
+  defsequence :blink_off, 25
 
   @doc "Image: positive. Normal foreground and background."
-  defsequence(:inverse_off, 27)
+  defsequence :inverse_off, 27
 
   @doc "Image: positive. Normal foreground and background."
-  defsequence(:reverse_off, 27)
+  defsequence :reverse_off, 27
 
   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)
+    defsequence color, code + 30
 
     @doc "Sets foreground color to light #{color}."
-    defsequence(:"light_#{color}", code + 90)
+    defsequence :"light_#{color}", code + 90
 
     @doc "Sets background color to #{color}."
-    defsequence(:"#{color}_background", code + 40)
+    defsequence :"#{color}_background", code + 40
 
     @doc "Sets background color to light #{color}."
-    defsequence(:"light_#{color}_background", code + 100)
+    defsequence :"light_#{color}_background", code + 100
   end
 
   @doc "Default text color."
-  defsequence(:default_color, 39)
+  defsequence :default_color, 39
 
   @doc "Default background color."
-  defsequence(:default_background, 49)
+  defsequence :default_background, 49
 
   @doc "Framed."
-  defsequence(:framed, 51)
+  defsequence :framed, 51
 
   @doc "Encircled."
-  defsequence(:encircled, 52)
+  defsequence :encircled, 52
 
   @doc "Overlined."
-  defsequence(:overlined, 53)
+  defsequence :overlined, 53
 
   @doc "Not framed or encircled."
-  defsequence(:not_framed_encircled, 54)
+  defsequence :not_framed_encircled, 54
 
   @doc "Not overlined."
-  defsequence(:not_overlined, 55)
+  defsequence :not_overlined, 55
 
   @doc "Sends cursor home."
-  defsequence(:home, "", "H")
-
-  @doc """
-  Sends cursor to the absolute position specified by `line` and `column`.
-
-  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"
+  defsequence :home, "", "H"
 
   @doc "Clears screen."
-  defsequence(:clear, "2", "J")
+  defsequence :clear, "2", "J"
 
   @doc "Clears line."
-  defsequence(:clear_line, "2", "K")
+  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"""
@@ -271,7 +243,7 @@ defmodule IO.ANSI do
   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

lib/elixir/lib/io/ansi/docs.ex

@@ -7,15 +7,14 @@ defmodule IO.ANSI.Docs do
   @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_inline_code`   - inline code (cyan)
-    * `:doc_table_heading` - the style for table headings
+    * `:doc_table_heading` - style for table headings
     * `:doc_title`         - top level heading (reverse, yellow)
     * `:doc_underline`     - underlined text (underline)
     * `:width`             - the width to format the text (80)
@@ -23,20 +22,16 @@ defmodule IO.ANSI.Docs do
   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],
+     doc_headings:      [:yellow],
+     doc_inline_code:   [:cyan],
+     doc_table_heading: [:reverse],
+     doc_title:         [:reverse, :yellow],
+     doc_underline:     [:underline],
+     width:             80]
   end
 
   @doc """
@@ -44,67 +39,24 @@ 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())
+    IO.puts IO.ANSI.reset
     options = Keyword.merge(default_options(), options)
-    width = options[:width]
+    width   = options[:width]
     padding = div(width + String.length(heading), 2)
     heading = heading |> String.pad_leading(padding) |> String.pad_trailing(width)
     write(:doc_title, heading, options)
     newline_after_block()
   end
 
-  @doc """
-  Prints documentation metadata (only `delegate_to`, `deprecated`, `guard`, and `since` 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, :guard, :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)
-
-      {key, value}, _printed when is_boolean(value) and key in @metadata_filter ->
-        IO.puts([metadata_label(key, options), ' ', to_string(value)])
-
-      {:delegate_to, {m, f, a}}, _printed ->
-        label = metadata_label(:delegate_to, options)
-        IO.puts([label, ' ', Exception.format_mfa(m, f, a)])
-
-      _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
-  end
-
   @doc """
   Prints the documentation body.
 
-  In addition to the printing string, takes a set of `options`
-  defined in `default_options/0`.
+  In addition to the printing string, takes a set of options
+  defined in `default_options/1`.
   """
-  @spec print(String.t(), keyword) :: :ok
   def print(doc, options \\ []) do
     options = Keyword.merge(default_options(), options)
-
     doc
     |> String.split(["\r\n", "\n"], trim: false)
     |> Enum.map(&String.trim_trailing/1)
@@ -118,23 +70,18 @@ defmodule IO.ANSI.Docs do
   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)
   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
@@ -159,16 +106,13 @@ defmodule IO.ANSI.Docs 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
@@ -190,15 +134,12 @@ 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
@@ -218,7 +159,6 @@ 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}
@@ -234,20 +174,14 @@ 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
@@ -330,7 +264,7 @@ defmodule IO.ANSI.Docs do
 
   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 =
@@ -342,7 +276,10 @@ defmodule IO.ANSI.Docs do
         end
       end
 
-    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
 
@@ -361,7 +298,6 @@ defmodule IO.ANSI.Docs do
       |> String.trim()
       |> handle_links
       |> handle_inline(options)
-
     {col, length_without_escape(col, 0)}
   end
 
@@ -374,7 +310,6 @@ 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)
@@ -392,7 +327,8 @@ 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
@@ -402,14 +338,14 @@ defmodule IO.ANSI.Docs do
     end
   end
 
-  defp table_header?(line) do
-    Enum.all?(line, fn {col, _} -> table_header_column?(col) end)
+  defp table_header?(row) do
+    Enum.all?(row, 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_column?(":" <> row), do: table_header_contents?(row)
+  defp table_header_column?(row), do: table_header_contents?(row)
 
-  defp table_header_contents?("-" <> rest), do: table_header_contents?(rest)
+  defp table_header_contents?("-" <> row), do: table_header_contents?(row)
   defp table_header_contents?(":"), do: true
   defp table_header_contents?(""), do: true
   defp table_header_contents?(_), do: false
@@ -426,27 +362,22 @@ defmodule IO.ANSI.Docs do
     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))
+    pad = if rem(length, 2) == 0, do: 1, else: rem(width, 2)
+    spaces = div(width, 2) - div(length, 2)
+    String.duplicate(" ", spaces) <> col <> String.duplicate(" ", spaces + pad)
   end
 
   defp generate_table_cell({{{col, length}, width}, :right}) do
-    ansi_diff = byte_size(col) - length
-    String.pad_leading(col, width + ansi_diff)
+    String.duplicate(" ", width - length) <> col
   end
 
-  defp generate_table_cell({{{col, length}, width}, :left}) do
-    ansi_diff = byte_size(col) - length
-    String.pad_trailing(col, width + ansi_diff)
+  defp generate_table_cell({{{col, length}, width}, _}) do
+    col <> String.duplicate(" ", width - length)
   end
 
   defp table_line?(line) do
@@ -463,11 +394,13 @@ 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
@@ -476,7 +409,7 @@ 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
 
@@ -524,24 +457,22 @@ defmodule IO.ANSI.Docs do
   end
 
   defp escape_underlines_in_link(text) do
-    # Regular expression adapted from https://tools.ietf.org/html/rfc3986#appendix-B
-    ~r{[a-z][a-z0-9\+\-\.]*://\S*}i
-    |> Regex.recompile!()
+    ~r{https?\S*}
+    |> Regex.recompile!
     |> Regex.replace(text, &String.replace(&1, "_", "\\_"))
   end
 
   defp remove_square_brackets_in_link(text) do
     ~r{\[(.*?)\]\((.*?)\)}
-    |> Regex.recompile!()
+    |> Regex.recompile!
     |> Regex.replace(text, "\\1 (\\2)")
   end
 
   # We have four entries: **, *, _ and `.
   #
   # The first three behave the same while the last one is simpler
-  # when it comes to delimiters as it ignores spaces and escape
-  # characters. But, since the first has two characters, we need to
-  # handle 3 cases:
+  # when it comes to delimiters. But, since the first has two
+  # characters, we need to handle 3 cases:
   #
   # 1. **
   # 2. _ and *
@@ -552,8 +483,7 @@ 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
 
@@ -572,29 +502,29 @@ defmodule IO.ANSI.Docs do
   # Inline delimiters
 
   defp handle_inline(<<delimiter, ?*, ?*, rest::binary>>, nil, buffer, acc, options)
-       when rest != "" and delimiter in @delimiters do
+      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
+      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
+      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
+      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
+      when rest != "" and mark in @single do
     handle_inline(rest, mark, [<<mark>>], [?\\, Enum.reverse(buffer) | acc], options)
   end
 
@@ -603,31 +533,30 @@ defmodule IO.ANSI.Docs do
   end
 
   # An escape is not valid inside `
-  defp handle_inline(<<?\\, mark, rest::binary>>, limit, buffer, acc, options) when limit != ?` do
+  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)
   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
+      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
+      when rest == "" and mark in @single do
     handle_inline(<<>>, nil, [], [inline_buffer(buffer, options) | acc], options)
   end
 
@@ -642,19 +571,19 @@ defmodule IO.ANSI.Docs do
   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])
+    [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
@@ -664,5 +593,5 @@ 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

lib/elixir/lib/io/stream.ex

@@ -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
@@ -17,7 +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
+    * `line_or_bytes` - if reading should read lines or a given amount 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.
@@ -42,12 +41,10 @@ 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 +53,10 @@ 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 +66,5 @@ defmodule IO.Stream do
     def member?(_stream, _term) do
       {:error, __MODULE__}
     end
-
-    def slice(_stream) do
-      {:error, __MODULE__}
-    end
   end
 end

lib/elixir/lib/kernel/cli.ex

@@ -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})
 
@@ -66,25 +55,21 @@ 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, reason, stacktrace),
+           pad(FunctionClauseError.blame(blamed, &inspect/1, &blame_match/2))]
         _ ->
           Exception.format_banner(kind, blamed, stacktrace)
       end
-
     [iodata, ?\n, Exception.format_stacktrace(prune_stacktrace(stacktrace))]
   end
 
@@ -105,23 +90,22 @@ 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 +113,6 @@ defmodule Kernel.CLI do
       {^pid, res} ->
         :erlang.demonitor(ref, [:flush])
         res
-
       {:DOWN, ^ref, _, _, other} ->
         print_error({:EXIT, pid}, other, [])
         {:shutdown, 1}
@@ -145,7 +128,6 @@ defmodule Kernel.CLI do
       {[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
@@ -154,15 +136,18 @@ defmodule Kernel.CLI do
   ## Error handling
 
   defp print_error(kind, reason, stacktrace) do
-    IO.write(:stderr, format_error(kind, reason, stacktrace))
+    IO.write :stderr, format_error(kind, reason, stacktrace)
   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
+  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
 
   defp blame_ansi(color, no_ansi, node) do
-    if IO.ANSI.enabled?() do
+    if IO.ANSI.enabled? do
       [color | Macro.to_string(node)]
       |> IO.ANSI.format(true)
       |> IO.iodata_to_binary()
@@ -175,9 +160,9 @@ defmodule Kernel.CLI 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]
+  @elixir_internals [:elixir, :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
     prune_stacktrace(t)
@@ -198,59 +183,54 @@ 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])
+    if function_exported?(IEx, :started?, 0) and IEx.started? do
+      IO.puts "IEx " <> System.build_info[:build]
     else
-      IO.puts(:erlang.system_info(:system_version))
-      IO.puts("Elixir " <> System.build_info()[:build])
+      IO.puts :erlang.system_info(:system_version)
+      IO.puts "Elixir " <> System.build_info[:build]
     end
 
-    System.halt(0)
+    System.halt 0
   end
 
   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
     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]})
+    parse_shared t, %{config | commands: [{:app, h} | config.commands]}
   end
 
   defp parse_shared(["--no-halt" | t], config) do
-    parse_shared(t, %{config | halt: false})
+    parse_shared t, %{config | halt: false}
   end
 
   defp parse_shared(["-e", h | t], config) do
-    parse_shared(t, %{config | commands: [{:eval, h} | config.commands]})
+    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]})
+    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]})
+    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", "--logger-otp-reports", "--logger-sasl-reports"] 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
@@ -259,9 +239,8 @@ defmodule Kernel.CLI do
 
   defp expand_code_path(path) do
     path = Path.expand(path)
-
     case Path.wildcard(path) do
-      [] -> [to_charlist(path)]
+      []   -> [to_charlist(path)]
       list -> Enum.map(list, &to_charlist/1)
     end
   end
@@ -273,11 +252,11 @@ defmodule Kernel.CLI do
   end
 
   defp parse_argv(["+elixirc" | t], config) do
-    parse_compiler(t, config)
+    parse_compiler t, config
   end
 
   defp parse_argv(["+iex" | t], config) do
-    parse_iex(t, config)
+    parse_iex t, config
   end
 
   defp parse_argv(["-S", h | t], config) do
@@ -287,8 +266,7 @@ defmodule Kernel.CLI 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}
@@ -309,40 +287,36 @@ defmodule Kernel.CLI do
   end
 
   defp parse_compiler(["-o", h | t], config) do
-    parse_compiler(t, %{config | output: h})
+    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]})
+    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})
+    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})
+    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})
+    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})
+    parse_compiler t, %{config | verbose_compile: true}
   end
 
   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
 
@@ -359,11 +333,11 @@ defmodule Kernel.CLI do
   # 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)
+    parse_iex t, config
   end
 
   defp parse_iex([opt, _ | t], config) when opt in ["--remsh"] do
-    parse_iex(t, config)
+    parse_iex t, config
   end
 
   defp parse_iex(["-S", h | t], config) do
@@ -372,8 +346,10 @@ defmodule Kernel.CLI 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 +360,22 @@ 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 +383,7 @@ 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 +391,7 @@ 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 +401,7 @@ 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 +411,7 @@ 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 +424,17 @@ 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)")]
+              [each_long_compilation: &IO.puts("Compiling #{&1} (it's taking more than 5s)")]
             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, opts)
+        end
       {:missing, missing} ->
         {:error, "No files matched pattern(s) #{Enum.join(missing, ",")}"}
     end
@@ -479,23 +442,23 @@ 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} ->
+      Enum.reduce patterns, {[], []}, fn pattern, {files, missing} ->
         case filter_patterns(pattern) do
           [] -> {files, [pattern | missing]}
           match -> {match ++ files, missing}
         end
-      end)
+      end
 
     case missing do
       [] -> {:ok, :lists.usort(files)}
-      _ -> {:missing, :lists.usort(missing)}
+      _  -> {:missing, :lists.usort(missing)}
     end
   end
 
@@ -513,7 +476,6 @@ defmodule Kernel.CLI do
         {:win32, _} ->
           base = Path.rootname(exec)
           if File.regular?(base), do: base, else: exec
-
         _ ->
           exec
       end

lib/elixir/lib/kernel/error_handler.ex

@@ -31,12 +31,11 @@ defmodule Kernel.ErrorHandler do
 
   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()})
+    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, :found}     -> true
       {^ref, :not_found} -> false
     end
   end

lib/elixir/lib/kernel/lexical_tracker.ex

@@ -6,7 +6,7 @@
 # any of the `GenServer.Behaviour` conveniences.
 defmodule Kernel.LexicalTracker do
   @moduledoc false
-  @timeout 30000
+  @timeout 30_000
   @behaviour :gen_server
 
   @doc """
@@ -23,19 +23,27 @@ defmodule Kernel.LexicalTracker do
     :gen_server.call(to_pid(arg), :remote_dispatches, @timeout)
   end
 
-  defp to_pid(pid) when is_pid(pid), do: pid
+  @doc """
+  Gets the destination the lexical scope is meant to
+  compile to.
+  """
+  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(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.
   @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
@@ -63,11 +71,6 @@ defmodule Kernel.LexicalTracker do
     :gen_server.cast(pid, {:remote_dispatch, module, fa, line, mode})
   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})
@@ -78,16 +81,6 @@ defmodule Kernel.LexicalTracker 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()
@@ -116,57 +109,45 @@ defmodule Kernel.LexicalTracker do
 
   # Callbacks
 
-  def init(:ok) do
-    state = %{
-      directives: %{},
-      references: %{},
-      compile: %{},
-      runtime: %{},
-      structs: %{},
-      cache: %{},
-      file: nil
-    }
-
-    {:ok, state}
+  def init(dest) do
+    {:ok, %{directives: %{}, references: %{}, compile: %{},
+            runtime: %{}, dest: dest, cache: %{}}}
   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
+      for {{^tag, module_or_mfa}, marker} <- state.directives,
+          is_integer(marker),
+          do: {module_or_mfa, marker}
 
     {:reply, Enum.sort(directives), state}
   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}
+    {:reply, partition(Enum.to_list(state.references), [], []), state}
   end
 
   def handle_call(:remote_dispatches, _from, state) do
     {:reply, {state.compile, state.runtime}, state}
   end
 
+  def handle_call(:dest, _from, state) do
+    {:reply, state.dest, state}
+  end
+
   def handle_call({:read_cache, key}, _from, %{cache: cache} = state) do
-    {:reply, :maps.get(key, cache), state}
+    {:reply, Map.fetch!(cache, key), state}
   end
 
   def handle_cast({:write_cache, key, value}, %{cache: cache} = state) do
-    {:noreply, %{state | cache: :maps.put(key, value, cache)}}
+    {:noreply, Map.put(state, :cache, Map.put(cache, key, value))}
   end
 
   def handle_cast({:remote_reference, module, mode}, state) do
     {:noreply, %{state | references: add_reference(state.references, module, mode)}}
   end
 
-  def handle_cast({:remote_struct, module, line}, state) do
-    state = add_remote_dispatch(state, module, {:__struct__, 0}, line, :compile)
-    structs = :maps.put(module, true, state.structs)
-    {:noreply, %{state | structs: structs}}
-  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)
@@ -186,19 +167,11 @@ defmodule Kernel.LexicalTracker 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()
+      |> :maps.from_list
       |> add_directive(module, line, warn, :import)
 
     directives =
@@ -234,42 +207,30 @@ defmodule Kernel.LexicalTracker do
 
   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}
+  defp partition([], compile, runtime),
+    do: {compile, runtime}
 
   # Callbacks helpers
 
+  defp add_reference(references, module, :runtime) when is_atom(module),
+    do: map_put_new(module, :runtime, references)
   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)
+  defp add_remote_dispatch(state, module, fa, line, mode) when is_atom(module) do
+    map_update mode, %{module => %{fa => [line]}}, state, fn mode_dispatches ->
+      map_update module, %{fa => [line]}, mode_dispatches, fn module_dispatches ->
+        map_update fa, [line], module_dispatches, &[line | List.delete(&1, line)]
+      end
     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)
@@ -295,4 +256,11 @@ defmodule Kernel.LexicalTracker do
       :error -> :maps.put(key, initial, map)
     end
   end
+
+  defp map_put_new(key, value, map) do
+    case :maps.find(key, map) do
+      {:ok, _} -> map
+      :error -> :maps.put(key, value, map)
+    end
+  end
 end

lib/elixir/lib/kernel/parallel_compiler.ex

@@ -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.
 
@@ -43,12 +11,11 @@ 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
@@ -57,251 +24,156 @@ defmodule Kernel.ParallelCompiler do
       timeout (see the `:long_compilation_threshold` option) to compile, invoke
       this callback passing the file as its argument
 
+    * `:long_compilation_threshold` - the timeout (in seconds) after the
+      `:each_long_compilation` callback is invoked; defaults to `10`
+
     * `: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`
+    * `:each_warning` - for each warning, invokes the callback passing
+      the file, line number, and warning message
 
     * `: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: Remove on 2.0
-  @doc false
-  @deprecated "Use Kernel.ParallelCompiler.compile/2 instead"
-  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: Remove on 2.0
-  @doc false
-  @deprecated "Use Kernel.ParallelCompiler.compile_to_path/2 instead"
-  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(%{
+      entries: files,
+      original: files,
+      output: path,
+      options: options,
+      waiting: [],
+      queued: [],
+      schedulers: schedulers,
+      result: [],
+    })
 
     # 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)
+  defp spawn_compilers(%{queued: queued, waiting: waiting, schedulers: schedulers} = state)
+      when length(queued) - length(waiting) >= schedulers do
+    wait_for_messages(state)
   end
 
   # Release waiting processes
-  defp spawn_workers([{ref, found} | t], waiting, queued, result, warnings, state) do
+  defp spawn_compilers(%{entries: [{ref, found} | t], waiting: waiting} = state) do
     waiting =
       case List.keytake(waiting, ref, 2) do
         {{_kind, pid, ^ref, _on, _defining}, waiting} ->
-          send(pid, {ref, found})
+          send pid, {ref, found}
           waiting
-
         nil ->
           waiting
       end
-
-    spawn_workers(t, waiting, queued, result, warnings, state)
+    spawn_compilers(%{state | entries: t, waiting: waiting})
   end
 
-  defp spawn_workers([file | files], waiting, queued, result, warnings, state) do
-    %{output: output, long_compilation_threshold: threshold, dest: dest} = state
+  defp spawn_compilers(%{entries: [file | files], queued: queued, output: output, options: options} = state) do
     parent = self()
 
     {pid, ref} =
-      :erlang.spawn_monitor(fn ->
+      :erlang.spawn_monitor fn ->
+        # 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
-
+            _ = if output do
+              :elixir_compiler.file_to_path(file, output)
+            else
+              :elixir_compiler.file(file, Keyword.get(options, :dest))
+            end
             :ok
           catch
             kind, reason ->
-              {kind, reason, __STACKTRACE__}
+              {kind, reason, System.stacktrace}
           end
 
-        send(parent, {:file_done, self(), file, result})
+        send(parent, {:file_compiled, self(), file, result})
         exit(:shutdown)
-      end)
+      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)
+    timeout = Keyword.get(options, :long_compilation_threshold, 10) * 1_000
+    timer_ref = Process.send_after(self(), {:timed_out, pid}, timeout)
+
+    new_queued = [{pid, ref, file, timer_ref} | queued]
+    spawn_compilers(%{state | entries: files, queued: new_queued})
   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(%{entries: [], waiting: [], queued: [], result: 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.
-    without_definition =
-      for {pid, _, _, _} <- queued,
-          entry = waiting_on_without_definition(waiting, pid),
-          do: entry
-
-    # 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 {:module, _, ref, on, _} <- without_definition,
-          do: {on, {ref, :not_found}}
+  defp spawn_compilers(%{entries: [], waiting: waiting, queued: queued} = state) when length(waiting) == length(queued) do
+    entries = for {pid, _, _, _} <- queued,
+                  entry = waiting_on_without_definition(waiting, pid),
+                  {_, _, ref, on, _} = entry,
+                  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
+    # 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
+    entries
     |> 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)
-
-      [] ->
-        # There is a deadlock. Instead of printing a deadlock, let's release
-        # structs, as a missing struct error is clearer than a deadlock one.
-        structs = for {:struct, _, ref, _, _} <- without_definition, do: {ref, :not_found}
-
-        if structs != [] do
-          spawn_workers(structs, waiting, queued, result, warnings, state)
-        else
-          errors = handle_deadlock(waiting, queued)
-          {:error, errors, warnings}
-        end
+      [{_on, refs} | _] -> spawn_compilers(%{state | entries: refs})
+      [] -> handle_deadlock(waiting, queued)
     end
   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)
+  defp spawn_compilers(%{entries: []} = state) do
+    wait_for_messages(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
@@ -310,39 +182,32 @@ defmodule Kernel.ParallelCompiler do
   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(state) do
+    %{entries: entries, options: options, waiting: waiting, queued: queued, result: result} = state
 
     receive do
       {:struct_available, module} ->
-        available =
-          for {:struct, _, ref, waiting_module, _defining} <- waiting,
-              module == waiting_module,
-              do: {ref, :found}
+        available = for {:struct, _, ref, waiting_module, _defining} <- waiting,
+                        module == waiting_module,
+                        do: {ref, :found}
 
-        result = [{:struct, module} | result]
-        spawn_workers(available ++ files, waiting, queued, result, warnings, state)
+        spawn_compilers(%{state | entries: available ++ entries, result: [{:struct, module} | result]})
 
       {:module_available, child, ref, file, module, binary} ->
-        state.each_module.(file, module, binary)
+        if callback = Keyword.get(options, :each_module) do
+          callback.(file, module, binary)
+        end
 
         # Release the module loader which is waiting for an ack
-        send(child, {ref, :ack})
+        send child, {ref, :ack}
 
-        available =
-          for {:module, _, ref, waiting_module, _defining} <- waiting,
-              module == waiting_module,
-              do: {ref, :found}
+        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)
+        spawn_compilers(%{state | entries: available ++ entries, result: [{:module, module} | result]})
 
       {:waiting, kind, child, ref, on, defining} ->
         # Oops, we already got it, do not put it on waiting.
@@ -350,59 +215,54 @@ defmodule Kernel.ParallelCompiler do
         # 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})
+            send child, {ref, :found}
             waiting
           else
             [{kind, child, ref, on, defining} | waiting]
           end
 
-        spawn_workers(files, waiting, queued, result, warnings, state)
+        spawn_compilers(%{state | waiting: waiting})
 
       {:timed_out, child} ->
+        callback = Keyword.get(options, :each_long_compilation)
         case List.keyfind(queued, child, 0) do
-          {^child, _, file, _} ->
-            state.each_long_compilation.(file)
-
+          {^child, _, file, _} when not is_nil(callback) ->
+            callback.(file)
           _ ->
             :ok
         end
-
-        spawn_workers(files, waiting, queued, result, warnings, state)
+        spawn_compilers(state)
 
       {: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)
+        if callback = Keyword.get(options, :each_warning) do
+          callback.(file, line, message)
+        end
+        wait_for_messages(state)
 
-      {:file_done, child_pid, file, :ok} ->
+      {:file_compiled, child_pid, file, :ok} ->
         discard_down(child_pid)
-        state.each_file.(file)
+
+        if callback = Keyword.get(options, :each_file) do
+          callback.(file)
+        end
+
         cancel_waiting_timer(queued, child_pid)
 
         # 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_entries = List.delete(entries, 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)
+        spawn_compilers(%{state | entries: new_entries, waiting: new_waiting, queued: new_queued})
 
-      {:file_done, child_pid, file, {kind, reason, stack}} ->
+      {:file_compiled, child_pid, file, {kind, reason, stack}} ->
         discard_down(child_pid)
         print_error(file, kind, reason, stack)
-        cancel_waiting_timer(queued, child_pid)
-
-        queued
-        |> List.keydelete(child_pid, 0)
-        |> terminate()
-
-        {:error, [to_error(file, kind, reason, stack)], warnings}
+        terminate(queued)
 
       {: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
+        handle_down(queued, ref, reason)
+        wait_for_messages(state)
     end
   end
 
@@ -415,18 +275,11 @@ defmodule Kernel.ParallelCompiler do
   defp handle_down(_queued, _ref, :normal) do
     :ok
   end
-
   defp handle_down(queued, ref, reason) do
     case List.keyfind(queued, ref, 1) do
-      {child_pid, ^ref, file, _timer_ref} ->
+      {_child, ^ref, file, _timer_ref} ->
         print_error(file, :exit, reason, [])
-
-        queued
-        |> List.keydelete(child_pid, 0)
-        |> terminate()
-
-        {:error, [to_error(file, :exit, reason, [])]}
-
+        terminate(queued)
       _ ->
         :ok
     end
@@ -438,48 +291,43 @@ defmodule Kernel.ParallelCompiler 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)
+        {_kind, ^pid, _, on, _} = List.keyfind(waiting, pid, 1)
+        error = CompileError.exception(description: "deadlocked waiting on module #{inspect on}",
+                                       file: nil, line: nil)
         print_error(file, :error, error, stacktrace)
 
-        {file, on, description}
+        {file, on}
       end
 
-    IO.puts("""
+    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()
+      |> Enum.map(& &1 |> elem(0) |> String.length)
+      |> Enum.max
 
-    for {file, mod, _} <- deadlock do
-      IO.puts(["  ", String.pad_leading(file, max), " => " | inspect(mod)])
+    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}
+    IO.puts ""
+    exit({:shutdown, 1})
   end
 
   defp terminate(queued) do
-    for {pid, _, _, _} <- queued, do: Process.exit(pid, :kill)
-    for {pid, _, _, _} <- queued, do: discard_down(pid)
-    :ok
+    for {pid, _, _, _} <- queued do
+      Process.exit(pid, :kill)
+    end
+    exit({:shutdown, 1})
   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)
-    ])
+    IO.write ["\n== Compilation error in file #{Path.relative_to_cwd(file)} ==\n",
+             Kernel.CLI.format_error(kind, reason, stack)]
   end
 
   defp cancel_waiting_timer(queued, child_pid) do
@@ -493,36 +341,8 @@ defmodule Kernel.ParallelCompiler do
         after
           0 -> :ok
         end
-
       nil ->
         :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

lib/elixir/lib/kernel/parallel_require.ex

@@ -1,18 +1,120 @@
 defmodule Kernel.ParallelRequire do
-  # TODO: Remove on 2.0
-  @moduledoc false
+  @moduledoc """
+  A module responsible for requiring files in parallel.
+  """
 
-  @deprecated "Use Kernel.ParallelCompiler.require/2 instead"
+  @doc """
+  Requires the given files.
+
+  A callback that will be invoked with each file, or a keyword list of `callbacks` can be provided:
+
+    * `:each_file` - invoked with each file
+
+    * `:each_module` - invoked with file, module name, and binary code
+
+  Returns the modules generated by each required file.
+  """
   def files(files, callbacks \\ [])
 
   def files(files, callback) when is_function(callback, 1) do
-    files(files, each_file: callback)
+    files(files, [each_file: callback])
   end
 
-  def files(files, options) when is_list(options) do
-    case Kernel.ParallelCompiler.require(files, options) do
-      {:ok, modules, _} -> modules
-      {:error, _, _} -> exit({:shutdown, 1})
+  def files(files, callbacks) when is_list(callbacks) do
+    compiler_pid = self()
+    :elixir_code_server.cast({:reset_warnings, compiler_pid})
+    schedulers = max(:erlang.system_info(:schedulers_online), 2)
+    result = spawn_requires(files, [], callbacks, 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, "\nExecution failed due to warnings while using the --warnings-as-errors option"
+        exit({:shutdown, 1})
     end
   end
+
+  defp spawn_requires([], [], _callbacks, _schedulers, result), do: result
+
+  defp spawn_requires([], waiting, callbacks, schedulers, result) do
+    wait_for_messages([], waiting, callbacks, schedulers, result)
+  end
+
+  defp spawn_requires(files, waiting, callbacks, schedulers, result) when length(waiting) >= schedulers do
+    wait_for_messages(files, waiting, callbacks, schedulers, result)
+  end
+
+  defp spawn_requires([file | files], waiting, callbacks, schedulers, result) do
+    parent = self()
+
+    {pid, ref} = :erlang.spawn_monitor fn ->
+      :erlang.put(:elixir_compiler_pid, parent)
+      :erlang.put(:elixir_compiler_file, file)
+
+      result =
+        try do
+          new = Code.require_file(file) || []
+          {:required, Enum.map(new, &elem(&1, 0))}
+        catch
+          kind, reason ->
+            {kind, reason, System.stacktrace}
+        end
+
+      send(parent, {:file_required, self(), file, result})
+      exit(:shutdown)
+    end
+
+    spawn_requires(files, [{pid, ref} | waiting], callbacks, schedulers, result)
+  end
+
+  defp wait_for_messages(files, waiting, callbacks, schedulers, result) do
+    receive do
+      {:file_required, pid, file, {:required, mods}} ->
+        discard_down(pid)
+        if each_file_callback = callbacks[:each_file] do
+          each_file_callback.(file)
+        end
+        waiting = List.keydelete(waiting, pid, 0)
+        spawn_requires(files, waiting, callbacks, schedulers, mods ++ result)
+
+      {:file_required, pid, _file, {kind, reason, stacktrace}} ->
+        discard_down(pid)
+        :erlang.raise(kind, reason, stacktrace)
+
+      {:DOWN, ref, :process, pid, reason} ->
+        handle_down(waiting, pid, ref, reason)
+        spawn_requires(files, waiting, callbacks, schedulers, result)
+
+      {:module_available, child, ref, file, module, binary} ->
+        if each_module_callback = callbacks[:each_module] do
+          each_module_callback.(file, module, binary)
+        end
+
+        send(child, {ref, :ack})
+        spawn_requires(files, waiting, callbacks, schedulers, result)
+
+      {:struct_available, _} ->
+        spawn_requires(files, waiting, callbacks, schedulers, result)
+
+      {:waiting, _, child, ref, _, _} ->
+        send(child, {ref, :not_found})
+        spawn_requires(files, waiting, callbacks, schedulers, result)
+    end
+  end
+
+  defp discard_down(pid) do
+    receive do
+      {:DOWN, _, :process, ^pid, _} -> :ok
+    end
+  end
+
+  defp handle_down(waiting, pid, ref, reason) do
+    if reason != :normal and {pid, ref} in waiting do
+      :erlang.raise(:exit, reason, [])
+    end
+    :ok
+  end
 end

lib/elixir/lib/kernel/special_forms.ex

@@ -4,7 +4,7 @@ defmodule Kernel.SpecialForms do
   cannot be overridden by the developer.
 
   We define them in this module. Some of these forms are lexical (like
-  `alias/2`, `case/2`, etc.). The macros `{}/1` and `<<>>/1` are also special
+  `alias/2`, `case/2`, etc). The macros `{}` and `<<>>` are also special
   forms used to define tuple and binary data structures respectively.
 
   This module also documents macros that return information about Elixir's
@@ -19,10 +19,7 @@ defmodule Kernel.SpecialForms do
   defmacrop error!(args) do
     quote do
       _ = unquote(args)
-
-      message =
-        "Elixir's special forms are expanded by the compiler and must not be invoked directly"
-
+      message = "Elixir's special forms are expanded by the compiler and must not be invoked directly"
       :erlang.error(RuntimeError.exception(message))
     end
   end
@@ -75,7 +72,7 @@ defmodule Kernel.SpecialForms do
   defmacro unquote(:%{})(args), do: error!([args])
 
   @doc """
-  Matches on or builds a struct.
+  Creates a struct.
 
   A struct is a tagged map that allows developers to provide
   default values for keys, tags to be used in polymorphic
@@ -96,25 +93,16 @@ defmodule Kernel.SpecialForms do
 
       %User{} == %{__struct__: User, name: "john", age: 27}
 
-  The struct fields can be given when building the struct:
+  A struct also validates that the given keys are part of the defined
+  struct. The example below will fail because there is no key
+  `:full_name` in the `User` struct:
 
-      %User{age: 31}
-      #=> %{__struct__: User, name: "john", age: 31}
-
-  Or also on pattern matching to extract values out:
-
-      %User{age: age} = user
+      %User{full_name: "john doe"}
 
   An update operation specific for structs is also available:
 
       %User{user | age: 28}
 
-  The advantage of structs is that they validate that the given
-  keys are part of the defined struct. The example below will fail
-  because there is no key `:full_name` in the `User` struct:
-
-      %User{full_name: "john doe"}
-
   The syntax above will guarantee the given keys are valid at
   compilation time and it will guarantee at runtime the given
   argument is a struct, failing with `BadStructError` otherwise.
@@ -125,24 +113,6 @@ defmodule Kernel.SpecialForms do
   can be used with protocols for polymorphic dispatch. Also
   see `Kernel.struct/2` and `Kernel.struct!/2` for examples on
   how to create and update structs dynamically.
-
-  ## Pattern matching on struct names
-
-  Besides allowing pattern matching on struct fields, such as:
-
-      %User{age: age} = user
-
-  Structs also allow pattern matching on the struct name:
-
-      %struct_name{} = user
-      struct_name #=> User
-
-  You can also assign the struct name to `_` when you want to
-  check if something is a struct but you are not interested in
-  its name:
-
-      %_{} = user
-
   """
   defmacro unquote(:%)(struct, map), do: error!([struct, map])
 
@@ -239,24 +209,6 @@ defmodule Kernel.SpecialForms do
       iex> {name, species}
       {"Frank", "Walrus"}
 
-  The size can be a variable:
-
-      iex> name_size = 5
-      iex> <<name::binary-size(name_size), " the ", species::binary>> = <<"Frank the Walrus">>
-      iex> {name, species}
-      {"Frank", "Walrus"}
-
-  And the variable can be defined in the match itself (prior to its use):
-
-      iex> <<name_size::size(8), name::binary-size(name_size), " the ", species::binary>> = <<5, "Frank the Walrus">>
-      iex> {name, species}
-      {"Frank", "Walrus"}
-
-  However, the size cannot be defined in the match outside the binary/bitstring match:
-
-      {name_size, <<name::binary-size(name_size), _rest::binary>>} = {5, <<"Frank the Walrus">>}
-      ** (CompileError): undefined variable "name_size" in bitstring segment
-
   Failing to specify the size for the non-last causes compilation to fail:
 
       <<name::binary, " the ", species::binary>> = <<"Frank the Walrus">>
@@ -339,7 +291,7 @@ defmodule Kernel.SpecialForms do
 
   Or as a part of function definitions to pattern match:
 
-      defmodule ImageTyper do
+      defmodule ImageTyper
         @png_signature <<137::size(8), 80::size(8), 78::size(8), 71::size(8),
                          13::size(8), 10::size(8), 26::size(8), 10::size(8)>>
         @jpg_signature <<255::size(8), 216::size(8)>>
@@ -376,7 +328,7 @@ defmodule Kernel.SpecialForms do
 
   The dot may be used to invoke anonymous functions too:
 
-      iex> (fn n -> n end).(7)
+      iex> (fn(n) -> n end).(7)
       7
 
   in which case there is a function on the left hand side.
@@ -391,7 +343,7 @@ defmodule Kernel.SpecialForms do
 
   ## Syntax
 
-  The right side of `.` may be a word starting with an uppercase letter, which represents
+  The right side of `.` may be a word starting in upcase, which represents
   an alias, a word starting with lowercase or underscore, any valid language
   operator or any name wrapped in single- or double-quotes. Those are all valid
   examples:
@@ -405,18 +357,21 @@ defmodule Kernel.SpecialForms do
       iex> Kernel.+(1, 2)
       3
 
-      iex> Kernel."+"(1, 2)
+      iex> Kernel."length"([1, 2, 3])
       3
 
-  Wrapping the function name in single- or double-quotes is always a
-  remote call. Therefore `Kernel."Foo"` will attempt to call the function "Foo"
-  and not return the alias `Kernel.Foo`. This is done by design as module names
-  are more strict than function names.
+      iex> Kernel.'+'(1, 2)
+      3
+
+  Note that `Kernel."FUNCTION_NAME"` will be treated as a remote call and not an alias.
+  This choice was done so every time single- or double-quotes are used, we have
+  a remote call regardless of the quote contents. This decision is also reflected
+  in the quoted expressions discussed below.
 
   When the dot is used to invoke an anonymous function there is only one
   operand, but it is still written using a postfix notation:
 
-      iex> negate = fn n -> -n end
+      iex> negate = fn(n) -> -n end
       iex> negate.(7)
       -7
 
@@ -440,7 +395,15 @@ defmodule Kernel.SpecialForms do
   with the name as first argument, some keyword list as metadata as second,
   and the list of arguments as third. In this case, the arguments are the
   alias `String` and the atom `:downcase`. The second argument in a remote call
-  is **always** an atom.
+  is **always** an atom regardless of the literal used in the call:
+
+      iex> quote do
+      ...>   String."downcase"("FOO")
+      ...> end
+      {{:., [], [{:__aliases__, [alias: false], [:String]}, :downcase]}, [], ["FOO"]}
+
+  The tuple containing `:.` is wrapped in another tuple, which actually
+  represents the function call, and has `"FOO"` as argument.
 
   In the case of calls to anonymous functions, the inner tuple with the dot
   special form has only one argument, reflecting the fact that the operator is
@@ -506,7 +469,7 @@ defmodule Kernel.SpecialForms do
       Keyword.values   #=> uses MyKeyword.values
       Elixir.Keyword.values #=> uses Keyword.values
 
-  Notice that calling `alias` without the `:as` option automatically
+  Notice that calling `alias` without the `as:` option automatically
   sets an alias based on the last part of the module. For example:
 
       alias Foo.Bar.Baz
@@ -566,7 +529,7 @@ defmodule Kernel.SpecialForms do
 
   ## Alias shortcut
 
-  `require/2` also accepts `:as` as an option so it automatically sets
+  `require/2` also accepts `as:` as an option so it automatically sets
   up an alias. Please check `alias/2` for more information.
 
   """
@@ -609,9 +572,8 @@ defmodule Kernel.SpecialForms do
       import List, only: [flatten: 1]
       import String, except: [split: 2]
 
-  Notice that calling `except` is always exclusive on a previously
-  declared `import/2`. If there is no previous import, then it applies
-  to all functions and macros in the module. For example:
+  Notice that calling `except` for a previously declared `import/2`
+  simply filters the previously imported elements. For example:
 
       import List, only: [flatten: 1, keyfind: 4]
       import List, except: [flatten: 1]
@@ -704,17 +666,6 @@ defmodule Kernel.SpecialForms do
   """
   defmacro __CALLER__, do: error!([])
 
-  @doc """
-  Returns the stacktrace for the currently handled exception.
-
-  It is available only in the `catch` and `rescue` clauses of `try/1`
-  expressions.
-
-  To retrieve the stacktrace of the current process, use
-  `Process.info(self(), :current_stacktrace)` instead.
-  """
-  defmacro __STACKTRACE__, do: error!([])
-
   @doc """
   Accesses an already bound variable in match clauses. Also known as the pin operator.
 
@@ -745,7 +696,7 @@ defmodule Kernel.SpecialForms do
       1
 
   """
-  defmacro ^var, do: error!([var])
+  defmacro ^(var), do: error!([var])
 
   @doc """
   Matches the value on the right against the pattern on the left.
@@ -783,7 +734,7 @@ defmodule Kernel.SpecialForms do
       ...> end
       {:sum, [], [1, 2, 3]}
 
-  ## Elixir's AST (Abstract Syntax Tree)
+  ## Explanation
 
   Any Elixir code can be represented using Elixir data structures.
   The building block of Elixir macros is a tuple with three elements,
@@ -803,42 +754,15 @@ defmodule Kernel.SpecialForms do
       function call. The third argument may be an atom, which is
       usually a variable (or a local call).
 
-  Besides the tuple described above, Elixir has a few literals that
-  are also part of its AST. Those literals return themselves when
-  quoted. They are:
-
-      :sum         #=> Atoms
-      1            #=> Integers
-      2.0          #=> Floats
-      [1, 2]       #=> Lists
-      "strings"    #=> Strings
-      {key, value} #=> Tuples with two elements
-
-  Any other value, such as a map or a four-element tuple, must be escaped
-  (`Macro.escape/1`) before being introduced into an AST.
-
   ## Options
 
-    * `:unquote` - when `false`, disables unquoting. This means any `unquote`
-      call will be kept as is in the AST, instead of replaced by the `unquote`
-      arguments. For example:
-
-          iex> quote do
-          ...>   unquote("hello")
-          ...> end
-          "hello"
-
-          iex> quote unquote: false do
-          ...>   unquote("hello")
-          ...> end
-          {:unquote, [], ["hello"]}
+    * `:unquote` - when `false`, disables unquoting. Useful when you have a quote
+      inside another quote and want to control what quote is able to unquote.
 
     * `:location` - when set to `:keep`, keeps the current line and file from
       quote. Read the Stacktrace information section below for more
       information.
 
-    * `:line` - sets the quoted expressions to have the given line.
-
     * `:generated` - marks the given chunk as generated so it does not emit warnings.
       Currently it only works on special forms (for example, you can annotate a `case`
       but not an `if`).
@@ -848,10 +772,22 @@ defmodule Kernel.SpecialForms do
     * `:bind_quoted` - passes a binding to the macro. Whenever a binding is
       given, `unquote/1` is automatically disabled.
 
+  ## Quote literals
+
+  Besides the tuple described above, Elixir has a few literals that
+  when quoted return themselves. They are:
+
+      :sum         #=> Atoms
+      1            #=> Integers
+      2.0          #=> Floats
+      [1, 2]       #=> Lists
+      "strings"    #=> Strings
+      {key, value} #=> Tuples with two elements
+
   ## Quote and macros
 
   `quote/2` is commonly used with macros for code generation. As an exercise,
-  let's define a macro that multiplies a number by itself (squared). In practice,
+  let's define a macro that multiplies a number by itself (squared). Note
   there is no reason to define such as a macro (and it would actually be
   seen as a bad practice), but it is simple enough that it allows us to focus
   on the important aspects of quotes and macros:
@@ -914,7 +850,7 @@ defmodule Kernel.SpecialForms do
         end
       end
 
-  Now invoking `squared(my_number.())` as before will print the value just
+  Now invoking `square(my_number.())` as before will print the value just
   once.
 
   In fact, this pattern is so common that most of the times you will want
@@ -930,7 +866,7 @@ defmodule Kernel.SpecialForms do
 
   `:bind_quoted` will translate to the same code as the example above.
   `:bind_quoted` can be used in many cases and is seen as good practice,
-  not only because it helps prevent us from running into common mistakes, but also
+  not only because it helps us from running into common mistakes but also
   because it allows us to leverage other tools exposed by macros, such as
   unquote fragments discussed in some sections below.
 
@@ -990,8 +926,8 @@ defmodule Kernel.SpecialForms do
       NoHygiene.interference
       a #=> 1
 
-  You cannot even access variables defined in the same module unless
-  you explicitly give it a context:
+  Note that you cannot even access variables defined in the same
+  module unless you explicitly give it a context:
 
       defmodule Hygiene do
         defmacro write do
@@ -1189,7 +1125,7 @@ defmodule Kernel.SpecialForms do
   When using `location: :keep` and invalid arguments are given to
   `Sample.add/2`, the stacktrace information will point to the file
   and line inside the quote. Without `location: :keep`, the error is
-  reported to where `defadd` was invoked. `location: :keep` affects
+  reported to where `defadd` was invoked. Note `location: :keep` affects
   only definitions inside the quote.
 
   ## Binding and unquote fragments
@@ -1268,61 +1204,37 @@ defmodule Kernel.SpecialForms do
   defmacro quote(opts, block), do: error!([opts, block])
 
   @doc """
-  Unquotes the given expression inside a quoted expression.
-
-  This function expects a valid Elixir AST, also known as
-  quoted expression, as argument. If you would like to `unquote`
-  any value, such as a map or a four-element tuple, you should
-  call `Macro.escape/1` before unquoting.
+  Unquotes the given expression from inside a macro.
 
   ## Examples
 
-  Imagine the situation you have a quoted expression and
+  Imagine the situation you have a variable `value` and
   you want to inject it inside some quote. The first attempt
   would be:
 
-      value =
-        quote do
-          13
-        end
-
+      value = 13
       quote do
         sum(1, value, 3)
       end
 
   Which would then return:
 
-      {:sum, [], [1, {:value, [], Elixir}, 3]}
+      {:sum, [], [1, {:value, [], quoted}, 3]}
 
-  Which is not the expected result. For this, we use `unquote`:
+  Which is not the expected result. For this, we use unquote:
 
-      iex> value =
-      ...>   quote do
-      ...>     13
-      ...>   end
+      iex> value = 13
       iex> quote do
       ...>   sum(1, unquote(value), 3)
       ...> end
       {:sum, [], [1, 13, 3]}
 
-  If you want to unquote a value that is not a quoted expression,
-  such as a map, you need to call `Macro.escape/1` before:
-
-      iex> value = %{foo: :bar}
-      iex> quote do
-      ...>   process_map(unquote(Macro.escape(value)))
-      ...> end
-      {:process_map, [], [{:%{}, [], [foo: :bar]}]}
-
-  If you forget to escape it, Elixir will raise an error
-  when compiling the code.
   """
   defmacro unquote(:unquote)(expr), do: error!([expr])
 
   @doc """
-  Unquotes the given list expanding its arguments.
-
-  Similar to `unquote/1`.
+  Unquotes the given list expanding its arguments. Similar
+  to `unquote/1`.
 
   ## Examples
 
@@ -1361,7 +1273,7 @@ defmodule Kernel.SpecialForms do
       iex> for n <- [1, 2, 3, 4, 5, 6], rem(n, 2) == 0, do: n
       [2, 4, 6]
 
-  Generators can also be used to filter as it removes any value
+  Note generators can also be used to filter as it removes any value
   that doesn't match the pattern on the left side of `<-`:
 
       iex> users = [user: "john", admin: "meg", guest: "barbara"]
@@ -1381,7 +1293,7 @@ defmodule Kernel.SpecialForms do
   filters or inside the block, are not reflected outside of the
   comprehension.
 
-  ## The `:into` and `:uniq` options
+  ## Into
 
   In the examples above, the result returned by the comprehension was
   always a list. The returned result can be configured by passing an
@@ -1401,57 +1313,6 @@ defmodule Kernel.SpecialForms do
         String.upcase(line)
       end
 
-  Similarly, `uniq: true` can also be given to comprehensions to guarantee
-  the results are only added to the collection if they were not returned
-  before. For example:
-
-      iex> for x <- [1, 1, 2, 3], uniq: true, do: x * 2
-      [2, 4, 6]
-
-      iex> for <<x <- "abcabc">>, uniq: true, into: "", do: <<x - 32>>
-      "ABC"
-
-  ## The `:reduce` option
-
-  While the `:into` option allows us to customize the comprehension behaviour
-  to a given data type, such as putting all of the values inside a map or inside
-  a binary, it is not always enough.
-
-  For example, imagine that you have a binary with letters where you want to
-  count how many times each lowercase letter happens, ignoring all uppercase
-  ones. For instance, for the string `"AbCabCABc"`, we want to return the map
-  `%{"a" => 1, "b" => 2, "c" => 1}`.
-
-  If we were to use `:into`, we would need a data type that computes the
-  frequency of each element it holds. While there is no such data type in
-  Elixir, you could implement one yourself.
-
-  A simpler option would be to use comprehensions for the mapping and
-  filtering of letters, and then we invoke `Enum.reduce/3` to build a map,
-  for example:
-
-      iex> letters = for <<x <- "AbCabCABc">>, x in ?a..?z, do: <<x>>
-      iex> Enum.reduce(letters, %{}, fn x, acc -> Map.update(acc, x, 1, & &1 + 1) end)
-      %{"a" => 1, "b" => 2, "c" => 1}
-
-  While the above is straight-forward, it has the downside of traversing the
-  data at least twice. If you are expecting long strings as inputs, this can
-  be quite expensive.
-
-  Luckily, comprehensions also support the `:reduce` option, which would allow
-  us to fuse both steps above into a single step:
-
-      iex> for <<x <- "AbCabCABc">>, x in ?a..?z, reduce: %{} do
-      ...>   acc -> Map.update(acc, <<x>>, 1, & &1 + 1)
-      ...> end
-      %{"a" => 1, "b" => 2, "c" => 1}
-
-  When the `:reduce` key is given, its value is used as the initial accumulator
-  and the `do` block must be changed to use `->` clauses, where the left side
-  of `->` receives the accumulated value of the previous iteration and the
-  expression on the right side must return the new accumulator value. Once there are no more
-  elements, the final accumulated value is returned. If there are no elements
-  at all, then the initial accumulator value is returned.
   """
   defmacro for(args), do: error!([args])
 
@@ -1462,9 +1323,8 @@ defmodule Kernel.SpecialForms do
 
       iex> opts = %{width: 10, height: 15}
       iex> with {:ok, width} <- Map.fetch(opts, :width),
-      ...>      {:ok, height} <- Map.fetch(opts, :height) do
-      ...>   {:ok, width * height}
-      ...> end
+      ...>      {:ok, height} <- Map.fetch(opts, :height),
+      ...>      do: {:ok, width * height}
       {:ok, 150}
 
   If all clauses match, the `do` block is executed, returning its result.
@@ -1472,55 +1332,30 @@ defmodule Kernel.SpecialForms do
 
       iex> opts = %{width: 10}
       iex> with {:ok, width} <- Map.fetch(opts, :width),
-      ...>      {:ok, height} <- Map.fetch(opts, :height) do
-      ...>   {:ok, width * height}
-      ...> end
+      ...>      {:ok, height} <- Map.fetch(opts, :height),
+      ...>      do: {:ok, width * height}
       :error
 
   Guards can be used in patterns as well:
 
       iex> users = %{"melany" => "guest", "bob" => :admin}
-      iex> with {:ok, role} when not is_binary(role) <- Map.fetch(users, "bob") do
-      ...>   {:ok, to_string(role)}
-      ...> end
+      iex> with {:ok, role} when not is_binary(role) <- Map.fetch(users, "bob"),
+      ...>      do: {:ok, to_string(role)}
       {:ok, "admin"}
 
-  As in `for/1`, variables bound inside `with/1` won't leak.
-  Expressions without `<-` may also be used in clauses. For instance,
-  you can perform regular matches with the `=` operator:
+  As in `for/1`, variables bound inside `with/1` won't leak;
+  "bare expressions" may also be inserted between the clauses:
 
       iex> width = nil
       iex> opts = %{width: 10, height: 15}
       iex> with {:ok, width} <- Map.fetch(opts, :width),
       ...>      double_width = width * 2,
-      ...>      {:ok, height} <- Map.fetch(opts, :height) do
-      ...>   {:ok, double_width * height}
-      ...> end
+      ...>      {:ok, height} <- Map.fetch(opts, :height),
+      ...>      do: {:ok, double_width * height}
       {:ok, 300}
       iex> width
       nil
 
-  The behaviour of any expression in a clause is the same as outside.
-  For example, `=` will raise a `MatchError` instead of returning the
-  non-matched value:
-
-      with :foo = :bar, do: :ok
-      #=> ** (MatchError) no match of right hand side value: :bar
-
-  As with any other function or macro call in Elixir, explicit parens can
-  also be used around the arguments before the `do`/`end` block:
-
-      iex> opts = %{width: 10, height: 15}
-      iex> with(
-      ...>   {:ok, width} <- Map.fetch(opts, :width),
-      ...>   {:ok, height} <- Map.fetch(opts, :height)
-      ...> ) do
-      ...>   {:ok, width * height}
-      ...> end
-      {:ok, 150}
-
-  The choice between parens and no parens is a matter of preference.
-
   An `else` option can be given to modify what is being returned from
   `with` in the case of a failed match:
 
@@ -1534,8 +1369,8 @@ defmodule Kernel.SpecialForms do
       ...> end
       {:error, :wrong_data}
 
-  If an `else` block is used and there are no matching clauses, a `WithClauseError`
-  exception is raised.
+  If there is no matching `else` condition, then a `WithClauseError` exception is raised.
+
   """
   defmacro with(args), do: error!([args])
 
@@ -1548,16 +1383,6 @@ defmodule Kernel.SpecialForms do
       iex> add.(1, 2)
       3
 
-  Anonymous functions can also have multiple clauses. All clauses
-  should expect the same number of arguments:
-
-      iex> negate = fn
-      ...>   true -> false
-      ...>   false -> true
-      ...> end
-      iex> negate.(false)
-      true
-
   """
   defmacro unquote(:fn)(clauses), do: error!([clauses])
 
@@ -1576,7 +1401,7 @@ defmodule Kernel.SpecialForms do
       {:__block__, [], [1, 2, 3]}
 
   """
-  defmacro unquote(:__block__)(args), do: error!([args])
+  defmacro __block__(args), do: error!([args])
 
   @doc """
   Captures or creates an anonymous function.
@@ -1612,18 +1437,11 @@ defmodule Kernel.SpecialForms do
       4
 
   In other words, `&(&1 * 2)` is equivalent to `fn x -> x * 2 end`.
+  Another example using a local function:
 
-  We can partially apply a remote function with placeholder:
-
-      iex> take_five = &Enum.take(&1, 5)
-      iex> take_five.(1..10)
-      [1, 2, 3, 4, 5]
-
-  Another example while using an imported or local function:
-
-      iex> first_elem = &elem(&1, 0)
-      iex> first_elem.({0, 1})
-      0
+      iex> fun = &is_atom(&1)
+      iex> fun.(:atom)
+      true
 
   The `&` operator can be used with more complex expressions:
 
@@ -1638,8 +1456,8 @@ defmodule Kernel.SpecialForms do
       {1, 2}
 
       iex> fun = &[&1 | &2]
-      iex> fun.(1, [2, 3])
-      [1, 2, 3]
+      iex> fun.(1, 2)
+      [1 | 2]
 
   The only restrictions when creating anonymous functions is that at
   least one placeholder must be present, i.e. it must contain at least
@@ -1686,7 +1504,7 @@ defmodule Kernel.SpecialForms do
     3. When the head element of aliases is the atom `:Elixir`, no expansion happens.
 
   """
-  defmacro unquote(:__aliases__)(args), do: error!([args])
+  defmacro __aliases__(args), do: error!([args])
 
   @doc """
   Calls the overridden function when overriding it with `Kernel.defoverridable/1`.
@@ -1818,15 +1636,14 @@ defmodule Kernel.SpecialForms do
         IO.puts "This is printed regardless if it failed or succeed"
       end
 
-  The `rescue` clause is used to handle exceptions while the `catch`
+  The `rescue` clause is used to handle exceptions, while the `catch`
   clause can be used to catch thrown values and exits.
   The `else` clause can be used to control flow based on the result of
   the expression. `catch`, `rescue`, and `else` clauses work based on
   pattern matching (similar to the `case` special form).
 
-  Calls inside `try/1` are not tail recursive since the VM needs to keep
-  the stacktrace in case an exception happens. To retrieve the stacktrace,
-  access `__STACKTRACE__/0` inside the `rescue` or `catch` clause.
+  Note that calls inside `try/1` are not tail recursive since the VM
+  needs to keep the stacktrace in case an exception happens.
 
   ## `rescue` clauses
 
@@ -1835,37 +1652,33 @@ defmodule Kernel.SpecialForms do
   exception by its name. All the following formats are valid patterns
   in `rescue` clauses:
 
-      # Rescue a single exception without binding the exception
-      # to a variable
       try do
         UndefinedModule.undefined_function
       rescue
         UndefinedFunctionError -> nil
       end
 
-      # Rescue any of the given exception without binding
       try do
         UndefinedModule.undefined_function
       rescue
-        [UndefinedFunctionError, ArgumentError] -> nil
+        [UndefinedFunctionError] -> nil
       end
 
-      # Rescue and bind the exception to the variable "x"
+      # rescue and bind to x
       try do
         UndefinedModule.undefined_function
       rescue
         x in [UndefinedFunctionError] -> nil
       end
 
-      # Rescue all kinds of exceptions and bind the rescued exception
-      # to the variable "x"
+      # rescue all and bind to x
       try do
         UndefinedModule.undefined_function
       rescue
         x -> nil
       end
 
-  ### Erlang errors
+  ## Erlang errors
 
   Erlang errors are transformed into Elixir ones when rescuing:
 
@@ -1874,18 +1687,16 @@ defmodule Kernel.SpecialForms do
       rescue
         ArgumentError -> :ok
       end
-      #=> :ok
 
   The most common Erlang errors will be transformed into their
-  Elixir counterpart. Those which are not will be transformed
-  into the more generic `ErlangError`:
+  Elixir counter-part. Those which are not will be transformed
+  into `ErlangError`:
 
       try do
         :erlang.error(:unknown)
       rescue
         ErlangError -> :ok
       end
-      #=> :ok
 
   In fact, `ErlangError` can be used to rescue any error that is
   not a proper Elixir error. For example, it can be used to rescue
@@ -1896,63 +1707,55 @@ defmodule Kernel.SpecialForms do
       rescue
         ErlangError -> :ok
       end
-      #=> :ok
 
-  ## `catch` clauses
+  ## Catching throws and exits
 
-  The `catch` clause can be used to catch thrown values, exits, and errors.
-
-  ### Catching thrown values
-
-  `catch` can be used to catch values thrown by `Kernel.throw/1`:
-
-      try do
-        throw(:some_value)
-      catch
-        thrown_value ->
-          IO.puts "A value was thrown: #{inspect(thrown_value)}"
-      end
-
-  ### Catching values of any kind
-
-  The `catch` clause also supports catching exits and errors. To do that, it
-  allows matching on both the *kind* of the caught value as well as the value
-  itself:
+  The `catch` clause can be used to catch thrown values and exits.
 
       try do
         exit(:shutdown)
       catch
-        :exit, value
-          IO.puts "Exited with value #{inspect(value)}"
+        :exit, :shutdown ->
+          IO.puts "Exited with shutdown reason"
       end
 
       try do
-        exit(:shutdown)
+        throw(:sample)
       catch
-        kind, value when kind in [:exit, :throw] ->
-          IO.puts "Caught exit or throw with value #{inspect(value)}"
+        :throw, :sample ->
+          IO.puts ":sample was thrown"
       end
 
-  The `catch` clause also supports `:error` alongside `:exit` and `:throw` as
-  in Erlang, although this is commonly avoided in favor of `raise`/`rescue` control
+  The `catch` clause also supports `:error` alongside `:exit` and `:throw`, as
+  in Erlang, although it is commonly avoided in favor of `raise`/`rescue` control
   mechanisms. One reason for this is that when catching `:error`, the error is
   not automatically transformed into an Elixir error:
 
       try do
         :erlang.error(:badarg)
       catch
-        :error, :badarg -> :ok
+        :error, :badarg ->
+          :ok
+      end
+
+  Note that it is possible to match both on the caught value as well as the *kind*
+  of such value:
+
+      try do
+        exit(:shutdown)
+      catch
+        kind, value when kind in [:exit, :throw] ->
+          IO.puts "Exited with or thrown value #{inspect(value)}"
       end
-      #=> :ok
 
   ## `after` clauses
 
   An `after` clause allows you to define cleanup logic that will be invoked both
-  when the block of code passed to `try/1` succeeds and also when an error is raised. Note
-  that the process will exit as usual when receiving an exit signal that causes
+  when the tried block of code succeeds and also when an error is raised. Note
+  that the process will exit as usually when receiving an exit signal that causes
   it to exit abruptly and so the `after` clause is not guaranteed to be executed.
   Luckily, most resources in Elixir (such as open files, ETS tables, ports, sockets,
-  and so on) are linked to or monitor the owning process and will automatically clean
+  etc.) are linked to or monitor the owning process and will automatically clean
   themselves up if that process exits.
 
       File.write!("tmp/story.txt", "Hello, World")
@@ -1964,7 +1767,7 @@ defmodule Kernel.SpecialForms do
 
   ## `else` clauses
 
-  `else` clauses allow the result of the body passed to `try/1` to be pattern
+  `else` clauses allow the result of the tried expression to be pattern
   matched on:
 
       x = 2
@@ -2001,7 +1804,7 @@ defmodule Kernel.SpecialForms do
         try do
           1 / x
         rescue
-          # The TryClauseError cannot be rescued here:
+          # The TryClauseError can not be rescued here:
           TryClauseError ->
             :error_a
         else
@@ -2096,10 +1899,10 @@ defmodule Kernel.SpecialForms do
   ## Examples
 
       receive do
-        {:selector, number, name} when is_integer(number) ->
-          name
-        name when is_atom(name) ->
-          name
+        {:selector, i, value} when is_integer(i) ->
+          value
+        value when is_atom(value) ->
+          value
         _ ->
           IO.puts :stderr, "Unexpected message received"
       end
@@ -2108,10 +1911,10 @@ defmodule Kernel.SpecialForms do
   received after the given timeout period, specified in milliseconds:
 
       receive do
-        {:selector, number, name} when is_integer(number) ->
-          name
-        name when is_atom(name) ->
-          name
+        {:selector, i, value} when is_integer(i) ->
+          value
+        value when is_atom(value) ->
+          value
         _ ->
           IO.puts :stderr, "Unexpected message received"
       after
@@ -2124,13 +1927,13 @@ defmodule Kernel.SpecialForms do
   one of the allowed values:
 
     * `:infinity` - the process should wait indefinitely for a matching
-      message, this is the same as not using the after clause
+      message, this is the same as not using a timeout
 
     * `0` - if there is no matching message in the mailbox, the timeout
       will occur immediately
 
-    * positive integer smaller than or equal to `4_294_967_295` (`0xFFFFFFFF`
-      in hexadecimal notation) - it should be possible to represent the timeout
+    * positive integer smaller than `4_294_967_295` (`0xFFFFFFFF`
+      in hex notation) - it should be possible to represent the timeout
       value as an unsigned 32-bit integer.
 
   ## Variables handling

lib/elixir/lib/kernel/utils.ex

@@ -6,13 +6,10 @@ defmodule Kernel.Utils do
   @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) 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)
 
   defp destructure_list(_, 0), do: []
   defp destructure_list([], count), do: destructure_nil(count)
@@ -57,8 +54,7 @@ defmodule Kernel.Utils do
   end
 
   defp validate_arg(ast) do
-    raise ArgumentError,
-          "defdelegate/2 only accepts function parameters, got: #{Macro.to_string(ast)}"
+    raise ArgumentError, "defdelegate/2 only accepts function parameters, got: #{Macro.to_string(ast)}"
   end
 
   @doc """
@@ -68,12 +64,11 @@ defmodule Kernel.Utils do
     case fields do
       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)
@@ -83,29 +78,22 @@ 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
+    :lists.foreach(fn
+      key when is_atom(key) -> :ok
+      key -> raise ArgumentError, "keys given to @enforce_keys must be atoms, got: #{inspect key}"
+    end, enforce_keys)
 
-      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)}
+    {:maps.put(:__struct__, module, :maps.from_list(fields)),
+     enforce_keys,
+     Module.get_attribute(module, :derive)}
   end
 
   @doc """
@@ -124,156 +112,14 @@ defmodule Kernel.Utils do
   def raise(msg) when is_binary(msg) do
     RuntimeError.exception(msg)
   end
-
-  def raise(module) when is_atom(module) do
-    module.exception([])
+  def raise(atom) when is_atom(atom) do
+    atom.exception([])
   end
-
-  def raise(%_{__exception__: true} = exception) do
+  def raise(%{__struct__: struct, __exception__: true} = exception) when is_atom(struct) 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
-    {guard, 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 do
-            true ->
-              case acc do
-                %{^pair => {new_var, _}} ->
-                  {new_var, acc}
-
-                %{} ->
-                  generated = String.to_atom("arg" <> Integer.to_string(map_size(acc)))
-                  new_var = Macro.var(generated, Elixir)
-                  {new_var, Map.put(acc, pair, {new_var, var})}
-              end
-
-            false ->
-              {var, acc}
-          end
-
-        node, acc ->
-          {node, acc}
-      end)
-
-    all_used = for ref <- :lists.reverse(refs), used = :maps.get(ref, used_refs, nil), do: used
-    {vars, exprs} = :lists.unzip(all_used)
-
-    quote do
-      {unquote_splicing(vars)} = {unquote_splicing(Enum.map(exprs, &literal_unquote/1))}
-      unquote(guard)
-    end
-  end
-
-  defp literal_quote(ast) do
-    {:quote, [], [[do: ast]]}
-  end
-
-  defp literal_unquote(ast) do
-    {:unquote, [], List.wrap(ast)}
-  end
-
-  defp var_context(meta, kind) do
-    case :lists.keyfind(:counter, 1, meta) do
-      {:counter, counter} -> counter
-      false -> kind
-    end
+    ArgumentError.exception("raise/1 expects a module name, string or exception as " <>
+                            "the first argument, got: #{inspect other}")
   end
 end

lib/elixir/lib/keyword.ex

@@ -20,22 +20,10 @@ defmodule Keyword do
       iex> [{:active, :once}]
       [active: :once]
 
-  The two syntaxes are completely equivalent. Like atoms, keywords
-  must be composed of Unicode characters such as letters, numbers,
-  underscore, and `@`. If the keyword has a character that does not
-  belong to the category above, 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. If you use quotes when all characters are a valid part
-  of a keyword without quotes, 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:
+  The two syntaxes are completely equivalent. 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)
 
@@ -84,7 +72,7 @@ defmodule Keyword do
 
       iex> Keyword.keyword?([])
       true
-      iex> Keyword.keyword?(a: 1)
+      iex> Keyword.keyword?([a: 1])
       true
       iex> Keyword.keyword?([{Foo, 1}])
       true
@@ -100,7 +88,7 @@ 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 """
@@ -131,7 +119,7 @@ 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
@@ -145,17 +133,16 @@ 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
 
@@ -262,32 +249,29 @@ defmodule Keyword do
   """
   @spec get_and_update(t, key, (value -> {get, value} | :pop)) :: {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
   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
@@ -322,7 +306,7 @@ defmodule Keyword do
       {1, []}
 
   """
-  @spec get_and_update!(t, key, (value -> {get, value})) :: {get, t} when get: term
+  @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
@@ -331,10 +315,8 @@ defmodule Keyword 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
@@ -382,7 +364,7 @@ defmodule Keyword do
       ** (KeyError) key :b not found in: [a: 1]
 
   """
-  @spec fetch!(t, key) :: value
+  @spec fetch!(t, key) :: value | no_return
   def fetch!(keywords, key) when is_list(keywords) and is_atom(key) do
     case :lists.keyfind(key, 1, keywords) do
       {^key, value} -> value
@@ -409,7 +391,6 @@ defmodule Keyword do
       {^key, val} -> {true, val}
       {_, _} -> false
     end
-
     :lists.filtermap(fun, keywords)
   end
 
@@ -420,9 +401,9 @@ defmodule Keyword do
 
   ## Examples
 
-      iex> Keyword.keys(a: 1, b: 2)
+      iex> Keyword.keys([a: 1, b: 2])
       [:a, :b]
-      iex> Keyword.keys(a: 1, b: 2, a: 3)
+      iex> Keyword.keys([a: 1, b: 2, a: 3])
       [:a, :b, :a]
 
   """
@@ -438,9 +419,9 @@ defmodule Keyword do
 
   ## Examples
 
-      iex> Keyword.values(a: 1, b: 2)
+      iex> Keyword.values([a: 1, b: 2])
       [1, 2]
-      iex> Keyword.values(a: 1, b: 2, a: 3)
+      iex> Keyword.values([a: 1, b: 2, a: 3])
       [1, 2, 3]
 
   """
@@ -468,22 +449,7 @@ 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 """
@@ -504,24 +470,8 @@ 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 """
@@ -539,22 +489,7 @@ 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 """
@@ -627,8 +562,22 @@ defmodule Keyword do
     end
   end
 
-  @doc false
-  @deprecated "Use Keyword.fetch/2 + Keyword.put/3 instead"
+  @doc """
+  Alters the value stored under `key` to `value`, but only
+  if the entry `key` already exists in the keyword list.
+
+  In the case a value is stored multiple times in the keyword list,
+  later occurrences are removed.
+
+  ## Examples
+
+      iex> Keyword.replace([a: 1], :b, 2)
+      [a: 1]
+      iex> Keyword.replace([a: 1, b: 2, a: 4], :a, 3)
+      [a: 3, b: 2]
+
+  """
+  @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)]
@@ -637,21 +586,17 @@ defmodule Keyword do
   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.
+  Similar to `replace/3`, but will raise a `KeyError`
+  if the entry `key` does not exist.
 
   ## 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
@@ -702,26 +647,17 @@ defmodule Keyword do
 
   """
   @spec merge(t, t) :: t
-  def merge(keywords1, keywords2)
-
-  def merge(keywords1, []) when is_list(keywords1), do: keywords1
-  def merge([], keywords2) when is_list(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,
-                "expected a keyword list as the first argument, got: #{inspect(keywords1)}"
+          raise ArgumentError, message: "expected a keyword list as the first argument, got: #{inspect keywords1}"
       end
-
       :lists.filter(fun, keywords1) ++ keywords2
     else
-      raise ArgumentError,
-            "expected a keyword list as the second argument, got: #{inspect(keywords2)}"
+      raise ArgumentError, message: "expected a keyword list as the second argument, got: #{inspect keywords2}"
     end
   end
 
@@ -744,38 +680,35 @@ defmodule Keyword do
       [b: 2, a: 4, d: 4]
 
       iex> Keyword.merge([a: 1, b: 2], [a: 3, d: 4, a: 5], fn :a, v1, v2 ->
-      ...>   v1 + v2
+      ...>  v1 + v2
       ...> end)
       [b: 2, a: 4, d: 4, a: 5]
 
       iex> Keyword.merge([a: 1, b: 2, a: 3], [a: 3, d: 4, a: 5], fn :a, v1, v2 ->
-      ...>   v1 + v2
+      ...>  v1 + v2
       ...> end)
       [b: 2, a: 4, d: 4, a: 8]
 
       iex> Keyword.merge([a: 1, b: 2], [:a, :b], fn :a, v1, v2 ->
-      ...>   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
+  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,
-            "expected a keyword list as the first argument, got: #{inspect(keywords1)}"
+      raise ArgumentError, message: "expected a keyword list as the first argument, got: #{inspect keywords1}"
     end
   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)
+        do_merge(tail, [{key, fun.(key, value1, value2)} | acc],
+                 delete(rest, key), :lists.keydelete(key, 1, original), fun, keywords2)
 
       false ->
         do_merge(tail, [{key, value2} | acc], rest, original, fun, keywords2)
@@ -787,8 +720,7 @@ defmodule Keyword do
   end
 
   defp do_merge(_other, _acc, _rest, _original, _fun, keywords2) do
-    raise ArgumentError,
-          "expected a keyword list as the second argument, got: #{inspect(keywords2)}"
+    raise ArgumentError, message: "expected a keyword list as the second argument, got: #{inspect keywords2}"
   end
 
   @doc """
@@ -826,7 +758,7 @@ defmodule Keyword do
       ** (KeyError) key :b not found in: [a: 1]
 
   """
-  @spec update!(t, key, (value -> value)) :: t
+  @spec update!(t, key, (value -> value)) :: t | no_return
   def update!(keywords, key, fun) do
     update!(keywords, key, fun, keywords)
   end
@@ -898,7 +830,7 @@ defmodule Keyword do
   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}
+        true  -> {[{k, v} | take], drop}
         false -> {take, [{k, v} | drop]}
       end
     end
@@ -968,7 +900,6 @@ defmodule Keyword do
     case fetch(keywords, key) do
       {:ok, value} ->
         {value, delete(keywords, key)}
-
       :error ->
         {default, keywords}
     end
@@ -1002,7 +933,6 @@ defmodule Keyword do
     case fetch(keywords, key) do
       {:ok, value} ->
         {value, delete(keywords, key)}
-
       :error ->
         {fun.(), keywords}
     end
@@ -1038,7 +968,7 @@ defmodule Keyword do
 
   ## Examples
 
-      iex> Keyword.to_list(a: 1)
+      iex> Keyword.to_list([a: 1])
       [a: 1]
 
   """
@@ -1049,7 +979,7 @@ defmodule Keyword do
 
   @doc false
   # TODO: Remove on 2.0
-  @deprecated "Use Kernel.length/1 instead"
+  # (hard-deprecated in elixir_dispatch)
   def size(keyword) do
     length(keyword)
   end

lib/elixir/lib/list.ex

@@ -2,19 +2,6 @@ defmodule List do
   @moduledoc """
   Functions that work on (linked) lists.
 
-  Many of the functions provided for lists, which implement
-  the `Enumerable` protocol, are found in the `Enum` module.
-
-  Additionally, the following functions and operators for lists are
-  found in `Kernel`:
-
-    * `++/2`
-    * `--/2`
-    * `hd/1`
-    * `tl/1`
-    * `in/2`
-    * `length/1`
-
   Lists in Elixir are specified between square brackets:
 
       iex> [1, "two", 3, :four]
@@ -58,15 +45,17 @@ defmodule List do
   slower as the list grows in size (linear time):
 
       iex> list = [1, 2, 3]
-      iex> [0 | list] # fast
+      iex> [0 | list]   # fast
       [0, 1, 2, 3]
-      iex> list ++ [4] # slow
+      iex> list ++ [4]  # slow
       [1, 2, 3, 4]
 
-  Additionally, 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.
+  The `Kernel` module contains many functions to manipulate lists
+  and that are allowed in guards. For example, `Kernel.hd/1` to
+  retrieve the head, `Kernel.tl/1` to fetch the tail and
+  `Kernel.length/1` for calculating the length. Keep in mind that,
+  similar to appending to a list, calculating the length needs to
+  traverse the whole list.
 
   ## Charlists
 
@@ -87,17 +76,25 @@ defmodule List do
   instead of Elixir strings. One example of such functions
   is `Application.loaded_applications/0`:
 
-      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'}
-      #=>  ]
+      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`.
+  ## List and Enum modules
+
+  This module aims to provide operations that are specific
+  to lists, like conversion between data types, updates,
+  deletions and key lookups (for lists of tuples). For traversing
+  lists in general, developers should use the functions in the
+  `Enum` module that work across a variety of data types.
+
+  In both `Enum` and `List` modules, any kind of index access
+  on a 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.
   """
 
   @compile :inline_list_funcs
@@ -177,16 +174,16 @@ 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 """
@@ -195,13 +192,13 @@ 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 """
@@ -220,7 +217,7 @@ defmodule List do
 
   """
   @spec first([elem]) :: nil | elem when elem: var
-  def first([]), do: nil
+  def first([]),      do: nil
   def first([head | _]), do: head
 
   @doc """
@@ -288,17 +285,14 @@ defmodule List do
   end
 
   @doc """
-  Receives a list of tuples and if the identified item by `key` at `position`
-  exists, it is replaced with `new_tuple`.
+  Receives a list of tuples and replaces the item
+  identified by `key` at `position` if it exists.
 
   ## Examples
 
       iex> List.keyreplace([a: 1, b: 2], :a, 0, {:a, 3})
       [a: 3, b: 2]
 
-      iex> List.keyreplace([a: 1, b: 2], :a, 1, {:a, 3})
-      [a: 1, b: 2]
-
   """
   @spec keyreplace([tuple], any, non_neg_integer, tuple) :: [tuple]
   def keyreplace(list, key, position, new_tuple) do
@@ -325,7 +319,7 @@ defmodule List do
 
   @doc """
   Receives a `list` of tuples and replaces the item
-  identified by `key` at `position` with `new_tuple`.
+  identified by `key` at `position`.
 
   If the item does not exist, it is added to the end of the `list`.
 
@@ -388,15 +382,15 @@ 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.
+  Wraps the argument in a list.
 
-  If `term` is already a list, it returns the list.
-  If `term` is `nil`, it returns an empty list.
+  If the argument is already a list, returns the list.
+  If the argument is `nil`, returns an empty list.
 
   ## Examples
 
@@ -410,11 +404,7 @@ 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
@@ -443,123 +433,10 @@ 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 ~S"""
-  Checks if `list` is a charlist made only of printable ASCII characters.
-
-  Takes an optional `limit` as a second argument. `ascii_printable?/2` only
-  checks the printability of the list up to the `limit`.
-
-  A printable charlist in Elixir contains only the printable characters in the
-  standard seven-bit ASCII character encoding, which are characters ranging from
-  32 to 126 in decimal notation, plus the following control characters:
-
-    * `?\a` - Bell
-    * `?\b` - Backspace
-    * `?\t` - Horizontal tab
-    * `?\n` - Line feed
-    * `?\v` - Vertical tab
-    * `?\f` - Form feed
-    * `?\r` - Carriage return
-    * `?\e` - Escape
-
-  For more information read the [Character groups](https://en.wikipedia.org/wiki/ASCII#Character_groups)
-  section in the Wikipedia article of the [ASCII](https://en.wikipedia.org/wiki/ASCII) standard.
-
-  ## 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"
-  @spec ascii_printable?(list, limit) :: boolean
-        when limit: :infinity | non_neg_integer
-  def ascii_printable?(list, limit \\ :infinity)
-      when is_list(list) and (limit == :infinity or (is_integer(limit) and limit >= 0)) do
-    ascii_printable_guarded?(list, limit)
-  end
-
-  defp ascii_printable_guarded?(_, 0) do
-    true
-  end
-
-  defp ascii_printable_guarded?([char | rest], counter)
-       when is_integer(char) and char >= 32 and char <= 126 do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\n | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\r | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\t | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\v | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\b | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\f | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\e | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([?\a | rest], counter) do
-    ascii_printable_guarded?(rest, decrement(counter))
-  end
-
-  defp ascii_printable_guarded?([], _counter), do: true
-  defp ascii_printable_guarded?(_, _counter), do: false
-
-  @compile {:inline, decrement: 1}
-  defp decrement(:infinity), do: :infinity
-  defp decrement(counter), do: counter - 1
-
-  @doc """
-  Returns `true` if `list` is an improper list. Otherwise returns `false`.
-
-  ## Examples
-
-     iex> List.improper?([1, 2 | 3])
-     true
-
-     iex> List.improper?([1, 2, 3])
-     false
-
-  """
-  @doc since: "1.8.0"
-  @spec improper?(maybe_improper_list) :: boolean
-  def improper?(list) when is_list(list) and length(list) >= 0, do: false
-  def improper?(list) when is_list(list), do: true
-
   @doc """
   Returns a list with `value` inserted at the specified `index`.
 
@@ -582,19 +459,11 @@ defmodule List do
 
   """
   @spec insert_at(list, integer, any) :: list
-  def insert_at(list, index, value) when is_list(list) and is_integer(index) do
-    case index do
-      -1 ->
-        list ++ [value]
-
-      _ when index < 0 ->
-        case length(list) + index + 1 do
-          index when index < 0 -> [value | list]
-          index -> do_insert_at(list, index, value)
-        end
-
-      _ ->
-        do_insert_at(list, index, value)
+  def insert_at(list, index, value) when is_integer(index) do
+    if index < 0 do
+      do_insert_at(list, length(list) + index + 1, value)
+    else
+      do_insert_at(list, index, value)
     end
   end
 
@@ -620,12 +489,9 @@ defmodule List do
 
   """
   @spec replace_at(list, integer, any) :: list
-  def replace_at(list, index, value) when is_list(list) and is_integer(index) do
+  def replace_at(list, index, value) when is_integer(index) do
     if index < 0 do
-      case length(list) + index do
-        index when index < 0 -> list
-        index -> do_replace_at(list, index, value)
-      end
+      do_replace_at(list, length(list) + index, value)
     else
       do_replace_at(list, index, value)
     end
@@ -653,12 +519,9 @@ defmodule List do
 
   """
   @spec update_at([elem], integer, (elem -> any)) :: list when elem: var
-  def update_at(list, index, fun) when is_list(list) and is_function(fun) and is_integer(index) do
+  def update_at(list, index, fun) when is_function(fun, 1) and is_integer(index) do
     if index < 0 do
-      case length(list) + index do
-        index when index < 0 -> list
-        index -> do_update_at(list, index, fun)
-      end
+      do_update_at(list, length(list) + index, fun)
     else
       do_update_at(list, index, fun)
     end
@@ -705,7 +568,6 @@ defmodule List do
       {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
     if index < 0 do
@@ -735,31 +597,30 @@ defmodule List do
       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
+  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.
 
-  Elixir supports conversions from charlists which contains any Unicode
-  codepoint.
+  Currently Elixir does not support conversions from charlists
+  which contains Unicode codepoints greater than 0xFF.
 
   Inlined by the compiler.
 
   ## Examples
 
-      iex> List.to_atom('Elixir')
-      :Elixir
-
-      iex> List.to_atom('🌢 Elixir')
-      :"🌢 Elixir"
+      iex> List.to_atom('elixir')
+      :elixir
 
   """
   @spec to_atom(charlist) :: atom
@@ -771,8 +632,8 @@ defmodule List do
   Converts a charlist to an existing atom. Raises an `ArgumentError`
   if the atom does not exist.
 
-  Elixir supports conversions from charlists which contains any Unicode
-  codepoint.
+  Currently Elixir does not support conversions from charlists
+  which contains Unicode codepoints greater than 0xFF.
 
   Inlined by the compiler.
 
@@ -782,10 +643,6 @@ defmodule List do
       iex> List.to_existing_atom('my_atom')
       :my_atom
 
-      iex> _ = :"🌢 Elixir"
-      iex> List.to_existing_atom('🌢 Elixir')
-      :"🌢 Elixir"
-
       iex> List.to_existing_atom('this_atom_will_never_exist')
       ** (ArgumentError) argument error
 
@@ -875,11 +732,8 @@ 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)
@@ -896,7 +750,7 @@ defmodule List do
 
         Please check the given list or call inspect/1 to get the list representation, got:
 
-        #{inspect(list)}
+        #{inspect list}
         """
     else
       result when is_binary(result) ->
@@ -910,58 +764,6 @@ defmodule List do
     end
   end
 
-  @doc """
-  Converts a list of integers representing codepoints, lists or
-  strings into a charlist.
-
-  Notice that this function expects a list of integers representing
-  UTF-8 codepoints. If you have a list of bytes, you must instead use
-  the [`:binary` module](http://www.erlang.org/doc/man/binary.html).
-
-  ## Examples
-
-      iex> List.to_charlist([0x00E6, 0x00DF])
-      'æß'
-
-      iex> List.to_charlist([0x0061, "bc"])
-      'abc'
-
-      iex> List.to_charlist([0x0064, "ee", ['p']])
-      'deep'
-
-  """
-  @doc since: "1.8.0"
-  @spec to_charlist(:unicode.charlist()) :: charlist()
-  def to_charlist(list) when is_list(list) do
-    try do
-      :unicode.characters_to_list(list)
-    rescue
-      ArgumentError ->
-        raise ArgumentError, """
-        cannot convert the given list to a charlist.
-
-        To be converted to a charlist, 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)}
-        """
-    else
-      result when is_list(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 """
   Returns a keyword list that represents an *edit script*.
 
@@ -975,142 +777,89 @@ defmodule List do
   corresponding key is `:del`), or left alone (if the corresponding key is
   `:eq`) in `list1` in order to be closer to `list2`.
 
-  See `myers_difference/3` if you want to handle nesting in the diff scripts.
-
   ## 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}]
+  @spec myers_difference(list, list) :: [{:eq | :ins | :del, list}] | nil
   def myers_difference(list1, list2) when is_list(list1) and is_list(list2) do
-    myers_difference_with_diff_script(list1, list2, nil)
+    path = {0, 0, list1, list2, []}
+    find_script(0, length(list1) + length(list2), [path])
   end
 
-  @doc """
-  Returns a keyword list that represents an *edit script* with nested diffs.
-
-  This is an extension of `myers_difference/2` where a `diff_script` function
-  can be given in case it is desired to compute nested differences. The function
-  may return a list with the inner edit script or `nil` in case there is no
-  such script. The returned inner edit script will be under the `:diff` key.
-
-  ## Examples
-
-      iex> List.myers_difference(["a", "db", "c"], ["a", "bc"], &String.myers_difference/2)
-      [eq: ["a"], diff: [del: "d", eq: "b", ins: "c"], del: ["c"]]
-
-  """
-  @doc since: "1.8.0"
-  @spec myers_difference(list, list, (term, term -> script | nil)) :: script
-        when script: [{:eq | :ins | :del | :diff, list}]
-  def myers_difference(list1, list2, diff_script)
-      when is_list(list1) and is_list(list2) and is_function(diff_script) do
-    myers_difference_with_diff_script(list1, list2, diff_script)
+  defp find_script(envelope, max, _paths) when envelope > max do
+    nil
   end
 
-  defp myers_difference_with_diff_script(list1, list2, diff_script) do
-    path = {0, list1, list2, []}
-    find_script(0, length(list1) + length(list2), [path], diff_script)
-  end
-
-  defp find_script(envelope, max, paths, diff_script) do
-    case each_diagonal(-envelope, envelope, paths, [], diff_script) do
+  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, diff_script)
+      {:next, paths} -> find_script(envelope + 1, max, paths)
     end
   end
 
   defp compact_reverse([], acc), do: acc
 
-  defp compact_reverse([{:diff, _} = fragment | rest], acc) do
-    compact_reverse(rest, [fragment | acc])
-  end
-
   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, _diff_script) when diag > limit do
-    {:next, :lists.reverse(next_paths)}
+  defp each_diagonal(diag, limit, _paths, next_paths) when diag > limit do
+    {:next, Enum.reverse(next_paths)}
   end
 
-  defp each_diagonal(diag, limit, paths, next_paths, diff_script) do
-    {path, rest} = proceed_path(diag, limit, paths, diff_script)
-
-    case follow_snake(path) do
-      {:cont, path} -> each_diagonal(diag + 2, limit, rest, [path | next_paths], diff_script)
-      {:done, edits} -> {:done, edits}
+  defp each_diagonal(diag, limit, paths, next_paths) do
+    {path, rest} = proceed_path(diag, limit, paths)
+    with {:cont, path} <- follow_snake(path) do
+      each_diagonal(diag + 2, limit, rest, [path | next_paths])
     end
   end
 
-  defp proceed_path(0, 0, [path], _diff_script), do: {path, []}
+  defp proceed_path(0, 0, [path]), do: {path, []}
 
-  defp proceed_path(diag, limit, [path | _] = paths, diff_script) when diag == -limit do
-    {move_down(path, diff_script), paths}
+  defp proceed_path(diag, limit, [path | _] = paths) when diag == -limit do
+    {move_down(path), paths}
   end
 
-  defp proceed_path(diag, limit, [path], diff_script) when diag == limit do
-    {move_right(path, diff_script), []}
+  defp proceed_path(diag, limit, [path]) when diag == limit do
+    {move_right(path), []}
   end
 
-  defp proceed_path(_diag, _limit, [path1, path2 | rest], diff_script) do
-    if elem(path1, 0) > elem(path2, 0) do
-      {move_right(path1, diff_script), [path2 | rest]}
+  defp proceed_path(_diag, _limit, [path1, path2 | rest]) do
+    if elem(path1, 1) > elem(path2, 1) do
+      {move_right(path1), [path2 | rest]}
     else
-      {move_down(path2, diff_script), [path2 | rest]}
+      {move_down(path2), [path2 | rest]}
     end
   end
 
-  defp move_right({y, [elem1 | rest1] = list1, [elem2 | rest2], edits}, diff_script)
-       when diff_script != nil do
-    if diff = diff_script.(elem1, elem2) do
-      {y + 1, rest1, rest2, [{:diff, diff} | edits]}
-    else
-      {y, list1, rest2, [{:ins, elem2} | edits]}
-    end
+  defp move_right({x, y, list1, [elem | rest], edits}) do
+    {x + 1, y, list1, rest, [{:ins, elem} | edits]}
   end
 
-  defp move_right({y, list1, [elem | rest], edits}, _diff_script) do
-    {y, list1, rest, [{:ins, elem} | edits]}
+  defp move_right({x, y, list1, [], edits}) do
+    {x + 1, y, list1, [], edits}
   end
 
-  defp move_right({y, list1, [], edits}, _diff_script) do
-    {y, list1, [], edits}
+  defp move_down({x, y, [elem | rest], list2, edits}) do
+    {x, y + 1, rest, list2, [{:del, elem} | edits]}
   end
 
-  defp move_down({y, [elem1 | rest1], [elem2 | rest2] = list2, edits}, diff_script)
-       when diff_script != nil do
-    if diff = diff_script.(elem1, elem2) do
-      {y + 1, rest1, rest2, [{:diff, diff} | edits]}
-    else
-      {y + 1, rest1, list2, [{:del, elem1} | edits]}
-    end
+  defp move_down({x, y, [], list2, edits}) do
+    {x, y + 1, [], list2, edits}
   end
 
-  defp move_down({y, [elem | rest], list2, edits}, _diff_script) do
-    {y + 1, rest, list2, [{:del, elem} | edits]}
+  defp follow_snake({x, y, [elem | rest1], [elem | rest2], edits}) do
+    follow_snake({x + 1, y + 1, rest1, rest2, [{:eq, elem} | edits]})
   end
 
-  defp move_down({y, [], list2, edits}, _diff_script) 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
+  defp follow_snake({_x, _y, [], [], edits}) do
     {:done, edits}
   end
 
@@ -1126,6 +875,10 @@ defmodule List do
     []
   end
 
+  defp do_replace_at(list, index, _value) when index < 0 do
+    list
+  end
+
   defp do_replace_at([_old | rest], 0, value) do
     [value | rest]
   end
@@ -1140,7 +893,7 @@ defmodule List do
     [value]
   end
 
-  defp do_insert_at(list, 0, value) do
+  defp do_insert_at(list, index, value) when index <= 0 do
     [value | list]
   end
 
@@ -1154,6 +907,10 @@ defmodule List do
     [fun.(value) | list]
   end
 
+  defp do_update_at(list, index, _fun) when index < 0 do
+    list
+  end
+
   defp do_update_at([head | tail], index, fun) do
     [head | do_update_at(tail, index - 1, fun)]
   end
@@ -1168,6 +925,10 @@ defmodule List do
     {default, :lists.reverse(acc)}
   end
 
+  defp do_pop_at(list, index, default, []) when index < 0 do
+    {default, list}
+  end
+
   defp do_pop_at([head | tail], 0, _default, acc) do
     {head, :lists.reverse(acc, tail)}
   end
@@ -1180,11 +941,8 @@ defmodule List do
 
   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
@@ -1203,5 +961,5 @@ 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

lib/elixir/lib/list/chars.ex

@@ -18,7 +18,7 @@ defprotocol List.Chars do
 
   @doc false
   # TODO: Remove by 2.0
-  @deprecated "Use List.Chars.to_charlist/1 instead"
+  # (hard-deprecated in elixir_dispatch)
   Kernel.def to_char_list(term) do
     __MODULE__.to_charlist(term)
   end
@@ -38,9 +38,9 @@ defimpl List.Chars, for: BitString do
 
   def to_charlist(term) do
     raise Protocol.UndefinedError,
-      protocol: @protocol,
-      value: term,
-      description: "cannot convert a bitstring to a charlist"
+             protocol: @protocol,
+                value: term,
+          description: "cannot convert a bitstring to a charlist"
   end
 end
 

lib/elixir/lib/macro/env.ex

@@ -28,7 +28,7 @@ defmodule Macro.Env do
       element is the function name and the second its arity; returns
       `nil` if not inside a function
     * `context` - the context of the environment; it can be `nil`
-      (default context), `:guard` (inside a guard) or `:match` (inside a match)
+      (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
     * `requires` - the list of required modules
@@ -38,67 +38,58 @@ defmodule Macro.Env do
     * `context_modules` - a list of modules defined in the current context
     * `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}`
 
+  The following fields are private and must not be accessed or relied on:
+
+    * `export_vars` - a list keeping all variables to be exported in a
+      construct (may be `nil`)
+    * `match_vars` - controls how "new" variables are handled. Inside a
+      match it is a list with all variables in a match. Outside of a match
+      is either `:warn` or `:apply`
+    * `prematch_vars` - a list of variables defined before a match (is
+      `nil` when not inside a match)
+
   """
 
   @type name_arity :: {atom, arity}
   @type file :: binary
   @type line :: non_neg_integer
   @type aliases :: [{module, module}]
-  @type macro_aliases :: [{module, {term, module}}]
+  @type macro_aliases :: [{module, {integer, module}}]
   @type context :: :match | :guard | nil
   @type requires :: [module]
   @type functions :: [{module, [name_arity]}]
   @type macros :: [{module, [name_arity]}]
   @type context_modules :: [module]
+  @type vars :: [{atom, atom | non_neg_integer}]
   @type lexical_tracker :: pid | nil
-  @type variable :: {atom, atom | term}
+  @type local :: atom | nil
 
-  @typep vars :: [variable]
-  @typep var_type :: :term
-  @typep var_version :: non_neg_integer
-  @typep unused_vars :: %{{variable, var_version} => non_neg_integer | false}
-  @typep current_vars :: %{variable => {var_version, var_type}}
-  @typep prematch_vars :: current_vars | :warn | :raise | :pin | :apply
-  @typep contextual_vars :: [atom]
+  @opaque export_vars :: vars | nil
+  @opaque match_vars :: vars | :warn | :apply
+  @opaque prematch_vars :: vars | nil
 
-  @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
-        }
+  @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,
+               match_vars: match_vars,
+               prematch_vars: prematch_vars,
+               lexical_tracker: lexical_tracker}
 
-  # TODO: Remove :vars field on v2.0
   def __struct__ do
-    %{
-      __struct__: __MODULE__,
+    %{__struct__: __MODULE__,
       module: nil,
       file: "nofile",
       line: 0,
@@ -111,43 +102,14 @@ defmodule Macro.Env do
       macro_aliases: [],
       context_modules: [],
       vars: [],
-      unused_vars: %{},
-      current_vars: %{},
-      prematch_vars: :warn,
       lexical_tracker: nil,
-      contextual_vars: []
-    }
+      export_vars: nil,
+      match_vars: :warn,
+      prematch_vars: nil}
   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) :: [variable]
-  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, variable) :: boolean()
-  def has_var?(env, var)
-
-  def has_var?(%{__struct__: Macro.Env, current_vars: current_vars}, var) do
-    Map.has_key?(current_vars, var)
+    Enum.reduce kv, __struct__(), fn {k, v}, acc -> :maps.update(k, v, acc) end
   end
 
   @doc """
@@ -156,23 +118,10 @@ defmodule Macro.Env do
   """
   @spec location(t) :: keyword
   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 +146,8 @@ 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 +155,6 @@ 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

lib/elixir/lib/map.ex

@@ -2,12 +2,6 @@ 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`:
 
@@ -21,7 +15,7 @@ defmodule Map do
 
   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
+  compared using the exact-equality operator (`===`). 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
@@ -32,8 +26,8 @@ defmodule Map do
       %{: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:
+  (such as `Map.get/3` or `Map.fetch/2`) or through the `[]` syntax provided by
+  the `Access` module:
 
       iex> map = %{a: 1, b: 2}
       iex> Map.fetch(map, :a)
@@ -43,9 +37,10 @@ defmodule Map do
       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`.
+  The alternative access syntax `map.key` is provided alongside `[]` when the
+  map has a `:key` 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
@@ -53,13 +48,7 @@ defmodule Map do
       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
+  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.
@@ -91,6 +80,16 @@ defmodule Map do
       iex> %{map | three: 3}
       ** (KeyError) key :three not found
 
+  ## Modules to work with maps
+
+  This module aims to provide functions that perform operations specific to maps
+  (like accessing keys, updating values, and so on). For traversing maps as
+  collections, developers should use the `Enum` module that works across a
+  variety of data types.
+
+  The `Kernel` module also provides a few functions to work with maps: for
+  example, `Kernel.map_size/1` to know the number of key-value pairs in a map or
+  `Kernel.is_map/1` to know if a term is a map.
   """
 
   @type key :: any
@@ -100,8 +99,6 @@ defmodule Map do
   @doc """
   Returns all keys from `map`.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.keys(%{a: 1, b: 2})
@@ -114,8 +111,6 @@ defmodule Map do
   @doc """
   Returns all values from `map`.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.values(%{a: 1, b: 2})
@@ -131,8 +126,6 @@ defmodule Map do
   Each key-value pair in the map is converted to a two-element tuple `{key,
   value}` in the resulting list.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.to_list(%{a: 1})
@@ -149,7 +142,7 @@ defmodule Map do
 
   ## Examples
 
-      iex> Map.new()
+      iex> Map.new
       %{}
 
   """
@@ -165,21 +158,21 @@ defmodule Map do
 
       iex> Map.new([{:b, 1}, {:a, 2}])
       %{a: 2, b: 1}
-      iex> Map.new(a: 1, a: 2, a: 3)
+      iex> Map.new([a: 1, a: 2, a: 3])
       %{a: 3}
 
   """
-  @spec new(Enumerable.t()) :: map
+  @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(%{__struct__: _} = 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()
+    |> Enum.to_list
+    |> :maps.from_list
   end
 
   @doc """
@@ -193,17 +186,17 @@ defmodule Map do
       %{a: :a, b: :b}
 
   """
-  @spec new(Enumerable.t(), (term -> {key, value})) :: map
+  @spec new(Enumerable.t, (term -> {key, value})) :: map
   def new(enumerable, transform) when is_function(transform, 1) do
     enumerable
-    |> Enum.to_list()
+    |> Enum.to_list
     |> new_transform(transform, [])
   end
 
   defp new_transform([], _fun, acc) do
     acc
-    |> :lists.reverse()
-    |> :maps.from_list()
+    |> :lists.reverse
+    |> :maps.from_list
   end
 
   defp new_transform([item | rest], fun, acc) do
@@ -213,8 +206,6 @@ defmodule Map do
   @doc """
   Returns whether the given `key` exists in the given `map`.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.has_key?(%{a: 1}, :a)
@@ -222,6 +213,7 @@ defmodule Map do
       iex> Map.has_key?(%{a: 1}, :b)
       false
 
+  Inlined by the compiler.
   """
   @spec has_key?(map, key) :: boolean
   def has_key?(map, key), do: :maps.is_key(key, map)
@@ -232,8 +224,6 @@ defmodule Map do
   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.
-
   ## Examples
 
       iex> Map.fetch(%{a: 1}, :a)
@@ -241,6 +231,7 @@ defmodule Map do
       iex> Map.fetch(%{a: 1}, :b)
       :error
 
+  Inlined by the compiler.
   """
   @spec fetch(map, key) :: {:ok, value} | :error
   def fetch(map, key), do: :maps.find(key, map)
@@ -252,8 +243,6 @@ defmodule Map do
   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.
-
   ## Examples
 
       iex> Map.fetch!(%{a: 1}, :a)
@@ -262,7 +251,7 @@ defmodule Map do
       ** (KeyError) key :b not found in: %{a: 1}
 
   """
-  @spec fetch!(map, key) :: value
+  @spec fetch!(map, key) :: value | no_return
   def fetch!(map, key) do
     :maps.get(key, map)
   end
@@ -284,25 +273,8 @@ defmodule Map do
     case map do
       %{^key => _value} ->
         map
-
       %{} ->
         put(map, key, value)
-
-      other ->
-        :erlang.error({:badmap, other})
-    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
@@ -312,20 +284,39 @@ defmodule Map do
   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.
+  ## Examples
 
-  Inlined by the compiler.
+      iex> Map.replace(%{a: 1}, :b, 2)
+      %{a: 1}
+      iex> Map.replace(%{a: 1, b: 2}, :a, 3)
+      %{a: 3, b: 2}
+
+  """
+  @spec replace(map, key, value) :: map
+  def replace(map, key, value) do
+    case map do
+      %{^key => _value} ->
+        put(map, key, value)
+      %{} ->
+        map
+      other ->
+        :erlang.error({:badmap, other})
+    end
+  end
+
+  @doc """
+  Similar to `replace/3`, but will raise a `KeyError`
+  if the key does not exist in the map.
 
   ## 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}
 
+  Inlined by the compiler.
   """
-  @doc since: "1.5.0"
   @spec replace!(map, key, value) :: map
   def replace!(map, key, value) do
     :maps.update(key, value, map)
@@ -357,10 +348,8 @@ defmodule Map do
     case map do
       %{^key => _value} ->
         map
-
       %{} ->
         put(map, key, fun.())
-
       other ->
         :erlang.error({:badmap, other})
     end
@@ -378,12 +367,12 @@ defmodule Map do
       %{a: 1, c: 3}
 
   """
-  @spec take(map, Enumerable.t()) :: map
+  @spec take(map, Enumerable.t) :: map
   def take(map, keys)
 
   def take(map, keys) when is_map(map) do
     keys
-    |> Enum.to_list()
+    |> Enum.to_list
     |> take(map, [])
   end
 
@@ -429,10 +418,8 @@ defmodule Map do
     case map do
       %{^key => value} ->
         value
-
       %{} ->
         default
-
       other ->
         :erlang.error({:badmap, other}, [map, key, default])
     end
@@ -465,10 +452,8 @@ defmodule Map do
     case map do
       %{^key => value} ->
         value
-
       %{} ->
         fun.()
-
       other ->
         :erlang.error({:badmap, other}, [map, key, fun])
     end
@@ -477,8 +462,6 @@ defmodule Map do
   @doc """
   Puts the given `value` under `key` in `map`.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.put(%{a: 1}, :b, 2)
@@ -486,6 +469,7 @@ defmodule Map do
       iex> Map.put(%{a: 1, b: 2}, :a, 3)
       %{a: 3, b: 2}
 
+  Inlined by the compiler.
   """
   @spec put(map, key, value) :: map
   def put(map, key, value) do
@@ -497,8 +481,6 @@ defmodule Map do
 
   If the `key` does not exist, returns `map` unchanged.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.delete(%{a: 1, b: 2}, :a)
@@ -506,6 +488,7 @@ defmodule Map do
       iex> Map.delete(%{b: 2}, :a)
       %{b: 2}
 
+  Inlined by the compiler.
   """
   @spec delete(map, key) :: map
   def delete(map, key), do: :maps.remove(key, map)
@@ -521,8 +504,6 @@ defmodule Map do
   side into the struct, even if the key is not part of the struct. Instead,
   use `Kernel.struct/2`.
 
-  Inlined by the compiler.
-
   ## Examples
 
       iex> Map.merge(%{a: 1, b: 2}, %{a: 3, d: 4})
@@ -533,12 +514,12 @@ 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, resolving conflicts through the given `callback`.
 
   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
+  `map2`). The value returned by `callback` is used as the value under `key` in
   the resulting map.
 
   ## Examples
@@ -550,19 +531,15 @@ defmodule Map do
 
   """
   @spec merge(map, map, (key, value, value -> value)) :: map
-  def merge(map1, map2, fun) when is_function(fun, 3) do
+  def merge(map1, map2, callback) when is_function(callback, 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)
+      :maps.fold fn key, val2, acc ->
+        update(acc, key, val2, fn val1 -> callback.(key, val1, val2) end)
+      end, 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)
+      :maps.fold fn key, val2, acc ->
+        update(acc, key, val2, fn val1 -> callback.(key, val2, val1) end)
+      end, map2, map1
     end
   end
 
@@ -587,10 +564,8 @@ defmodule Map do
     case map do
       %{^key => value} ->
         put(map, key, fun.(value))
-
       %{} ->
         put(map, key, initial)
-
       other ->
         :erlang.error({:badmap, other}, [map, key, initial, fun])
     end
@@ -615,9 +590,13 @@ 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
-      :error -> {default, map}
+    case map do
+      %{^key => value} ->
+        {value, delete(map, key)}
+      %{} ->
+        {default, map}
+      other ->
+        :erlang.error({:badmap, other}, [map, key, default])
     end
   end
 
@@ -650,10 +629,8 @@ defmodule Map do
     case map do
       %{^key => value} ->
         {value, delete(map, key)}
-
       %{} ->
         {fun.(), map}
-
       other ->
         :erlang.error({:badmap, other}, [map, key, fun])
     end
@@ -670,12 +647,12 @@ defmodule Map do
       %{a: 1, c: 3}
 
   """
-  @spec drop(map, Enumerable.t()) :: map
+  @spec drop(map, Enumerable.t) :: map
   def drop(map, keys)
 
   def drop(map, keys) when is_map(map) do
     keys
-    |> Enum.to_list()
+    |> Enum.to_list
     |> drop_list(map)
   end
 
@@ -684,7 +661,6 @@ defmodule Map do
   end
 
   defp drop_list([], acc), do: acc
-
   defp drop_list([key | rest], acc) do
     drop_list(rest, delete(acc, key))
   end
@@ -703,12 +679,12 @@ defmodule Map do
       {%{a: 1, c: 3}, %{b: 2}}
 
   """
-  @spec split(map, Enumerable.t()) :: {map, map}
+  @spec split(map, Enumerable.t) :: {map, map}
   def split(map, keys)
 
   def split(map, keys) when is_map(map) do
     keys
-    |> Enum.to_list()
+    |> Enum.to_list
     |> split([], map)
   end
 
@@ -724,7 +700,6 @@ defmodule Map do
     case excluded do
       %{^key => value} ->
         split(rest, [{key, value} | included], delete(excluded, key))
-
       _other ->
         split(rest, included, excluded)
     end
@@ -760,7 +735,7 @@ defmodule Map do
   (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)`).
+  returned (making this function behave like `Map.pop(map, key)`.
 
   The returned value is a tuple with the "get" value returned by
   `fun` and a new map with the updated value under `key`.
@@ -791,10 +766,8 @@ defmodule Map do
     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)}"
     end
@@ -824,18 +797,15 @@ defmodule Map do
       {1, %{}}
 
   """
-  @spec get_and_update!(map, key, (value -> {get, value} | :pop)) :: {get, map}
-        when get: term
+  @spec get_and_update!(map, key, (value -> {get, value})) :: {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)}"
     end
@@ -893,7 +863,7 @@ defmodule Map do
 
   @doc false
   # TODO: Remove on 2.0
-  @deprecated "Use Kernel.map_size/1 instead"
+  # (hard-deprecated in elixir_dispatch)
   def size(map) do
     map_size(map)
   end

lib/elixir/lib/map_set.ex

@@ -5,7 +5,7 @@ defmodule MapSet do
   `MapSet` is the "go to" set data structure in Elixir. A set can be constructed
   using `MapSet.new/0`:
 
-      iex> MapSet.new()
+      iex> MapSet.new
       #MapSet<[]>
 
   A set can contain any kind of elements, and elements in a set don't have to be
@@ -13,7 +13,7 @@ defmodule MapSet do
   inserting an element in a set where it's already present, the insertion is
   simply a no-op.
 
-      iex> map_set = MapSet.new()
+      iex> map_set = MapSet.new
       iex> MapSet.put(map_set, "foo")
       #MapSet<["foo"]>
       iex> map_set |> MapSet.put("foo") |> MapSet.put("foo")
@@ -32,16 +32,11 @@ defmodule MapSet do
   structures: for example, see `MapSet.new/1` or `Enum.into/2`.
   """
 
-  # MapSets have an underlying Map. MapSet elements are keys of said map,
-  # and this empty list is their associated dummy value.
-  @dummy_value []
-
   @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
 
   @doc """
@@ -49,7 +44,7 @@ defmodule MapSet do
 
   ## Examples
 
-      iex> MapSet.new()
+      iex> MapSet.new
       #MapSet<[]>
 
   """
@@ -67,15 +62,14 @@ defmodule MapSet do
       #MapSet<[1, 2, 3]>
 
   """
-  @spec new(Enum.t()) :: t
+  @spec new(Enum.t) :: t
   def new(enumerable)
 
   def new(%__MODULE__{} = map_set), do: map_set
-
   def new(enumerable) do
     map =
       enumerable
-      |> Enum.to_list()
+      |> Enum.to_list
       |> new_from_list([])
 
     %MapSet{map: map}
@@ -90,11 +84,11 @@ defmodule MapSet do
       #MapSet<[2, 4]>
 
   """
-  @spec new(Enum.t(), (term -> val)) :: t(val) when val: value
+  @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()
+      |> Enum.to_list
       |> new_from_list_transform(transform, [])
 
     %MapSet{map: map}
@@ -105,15 +99,14 @@ defmodule MapSet do
   end
 
   defp new_from_list([item | rest], acc) do
-    new_from_list(rest, [{item, @dummy_value} | acc])
+    new_from_list(rest, [{item, []} | 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])
+    new_from_list_transform(rest, fun, [{fun.(item), []} | acc])
   end
 
   @doc """
@@ -154,8 +147,8 @@ defmodule MapSet do
       when map_size(map1) < map_size(map2) * 2 do
     map =
       map1
-      |> Map.keys()
-      |> filter_not_in(map2, [])
+      |> Map.keys
+      |> filter_not_in(map2)
 
     %MapSet{map: map}
   end
@@ -167,13 +160,16 @@ defmodule MapSet do
     %{map_set | map: Map.drop(map1, Map.keys(map2))}
   end
 
+  defp filter_not_in(keys, map2, acc \\ [])
   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
+    acc =
+      if Map.has_key?(map2, key) do
+        acc
+      else
+        [{key, []} | acc]
+      end
+    filter_not_in(rest, map2, acc)
   end
 
   @doc """
@@ -192,25 +188,24 @@ defmodule MapSet do
     {map1, map2} = order_by_size(map1, map2)
 
     map1
-    |> Map.keys()
+    |> 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)
+    case Map.has_key?(map2, key) do
+      true -> false
+      false -> none_in?(rest, map2)
     end
   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
 
@@ -262,7 +257,7 @@ 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 """
@@ -278,7 +273,7 @@ defmodule MapSet do
   """
   @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)}
+    %{map_set | map: Map.put(map, value, [])}
   end
 
   @doc """
@@ -312,7 +307,7 @@ defmodule MapSet do
   def subset?(%MapSet{map: map1}, %MapSet{map: map2}) do
     if map_size(map1) <= map_size(map2) do
       map1
-      |> Map.keys()
+      |> Map.keys
       |> map_subset?(map2)
     else
       false
@@ -320,9 +315,12 @@ defmodule MapSet do
   end
 
   defp map_subset?([], _), do: true
-
   defp map_subset?([key | rest], map2) do
-    match?(%{^key => _}, map2) and map_subset?(rest, map2)
+    if Map.has_key?(map2, key) do
+      map_subset?(rest, map2)
+    else
+      false
+    end
   end
 
   @doc """
@@ -354,43 +352,27 @@ defmodule MapSet do
   def union(%MapSet{map: map1, version: version} = map_set, %MapSet{map: map2, version: version}) do
     %{map_set | map: Map.merge(map1, map2)}
   end
-
   def union(%MapSet{map: map1}, %MapSet{map: map2}) do
     map = new_from_list(Map.keys(map1) ++ Map.keys(map2), [])
     %MapSet{map: map}
   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(map_set, acc, fun), do: Enumerable.List.reduce(MapSet.to_list(map_set), acc, fun)
+    def member?(map_set, val), do: {:ok, MapSet.member?(map_set, val)}
+    def count(map_set), do: {:ok, MapSet.size(map_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
+        map_set, {:cont, x} -> MapSet.put(map_set, x)
+        map_set, :done -> map_set
         _, :halt -> :ok
-      end
-
-      {[], fun}
+      end}
     end
   end
 
@@ -398,8 +380,7 @@ defmodule MapSet do
     import Inspect.Algebra
 
     def inspect(map_set, opts) do
-      opts = %Inspect.Opts{opts | charlists: :as_lists}
-      concat(["#MapSet<", Inspect.List.inspect(MapSet.to_list(map_set), opts), ">"])
+      concat ["#MapSet<", Inspect.List.inspect(MapSet.to_list(map_set), opts), ">"]
     end
   end
 end

lib/elixir/lib/module/locals_tracker.ex

@@ -4,113 +4,168 @@
 #
 # ## 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
 
-  @doc """
-  Adds and tracks defaults for a definition into the tracker.
-  """
-  def add_defaults({_set, bag}, _kind, {name, arity} = pair, defaults, meta) do
-    for i <- :lists.seq(arity - defaults, arity - 1) do
-      put_edge(bag, {:local, {name, i}}, {pair, get_line(meta)})
-    end
+  @timeout   30_000
+  @behaviour :gen_server
 
-    :ok
+  @type ref :: pid | module
+  @type name :: atom
+  @type name_arity :: {name, arity}
+
+  @type local :: {name, arity}
+  @type import :: {:import, name, arity}
+
+  # Public API
+
+  @doc """
+  Returns all imported modules that had the given
+  `{name, arity}` invoked.
+  """
+  @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, meta) when is_tuple(from) and is_tuple(to) do
-    if from != to do
-      put_edge(bag, {:local, from}, {to, get_line(meta)})
-    end
+  Returns all locals that are reachable.
 
-    :ok
+  By default, all public functions are reachable.
+  A private function is only reachable if it has
+  a public function that it invokes directly.
+  """
+  @spec reachable(ref) :: [local]
+  def reachable(ref) do
+    ref
+    |> to_pid()
+    |> :gen_server.call(:digraph, @timeout)
+    |> reachable_from(:local)
+    |> :sets.to_list()
   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
+  defp reachable_from(d, starting) do
+    reduce_reachable(d, starting, :sets.new)
   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}))
+  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
 
-  @doc """
-  Reattach a previously yanked node.
-  """
-  def reattach({_set, bag}, tuple, _kind, function, out_neighbours, meta) do
-    for out_neighbour <- out_neighbours do
-      put_edge(bag, {:local, function}, out_neighbour)
-    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)
+    :ets.lookup_element(table, {:elixir, :locals_tracker}, 2)
+  end
 
-    # Make a call from the old function to the new one
-    if function != tuple do
-      put_edge(bag, {:local, function}, {tuple, get_line(meta)})
-    end
+  # Internal API
 
-    # Finally marked the new one as reattached
-    put_edge(bag, :reattach, tuple)
-    :ok
+  # 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 an 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, tuple, kind, function, neighbours) do
+    :gen_server.cast(to_pid(pid), {:reattach, tuple, kind, function, neighbours})
   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}}
+  def collect_imports_conflicts(pid, all_defined) do
+    d = :gen_server.call(pid, :digraph, @timeout)
+
+    for {{name, arity}, _, meta, _} <- all_defined,
+        :digraph.in_neighbours(d, {:import, name, arity}) != [],
+        n = :digraph.out_neighbours(d, {:import, name, arity}),
+        n != [] do
+      {meta, {n, name, arity}}
     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))
+  # 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)
+    reachable = reachable_from(d, :local)
+    reattached = :digraph.out_neighbours(d, :reattach)
     {unreachable(reachable, reattached, private), collect_warnings(reachable, private)}
   end
 
-  @doc """
-  Collect undefined functions based on local calls and existing definitions
-  """
-  def collect_undefined_locals({set, bag}, all_defined) do
-    undefined =
-      for {pair, _, _, _} <- all_defined,
-          {local, line} <- out_neighbours(bag, {:local, pair}),
-          not :ets.member(set, {:def, local}),
-          do: {build_meta(line), local}
-
-    :lists.usort(undefined)
-  end
-
   defp unreachable(reachable, reattached, private) do
     for {tuple, kind, _, _} <- private,
         not reachable?(tuple, kind, reachable, reattached),
@@ -120,11 +175,10 @@ defmodule Module.LocalsTracker do
   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)
+    :lists.member(tuple, reattached) and :sets.is_element(tuple, reachable)
   end
-
   defp reachable?(tuple, :defp, reachable, _reattached) do
-    Map.has_key?(reachable, tuple)
+    :sets.is_element(tuple, reachable)
   end
 
   defp collect_warnings(reachable, private) do
@@ -136,7 +190,7 @@ defmodule Module.LocalsTracker do
   end
 
   defp collect_warnings({tuple, kind, meta, 0}, acc, reachable) do
-    if Map.has_key?(reachable, tuple) do
+    if :sets.is_element(tuple, reachable) do
       acc
     else
       [{meta, {:unused_def, tuple, kind}} | acc]
@@ -157,68 +211,140 @@ defmodule Module.LocalsTracker do
   end
 
   defp min_reachable_default(max, min, last, name, reachable) when max >= min do
-    case Map.has_key?(reachable, {name, max}) do
+    case :sets.is_element({name, max}, reachable) 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`.
-
-  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()
+  # Stops the gen server
+  @doc false
+  def stop(pid) do
+    :gen_server.cast(pid, :stop)
   end
 
-  defp reachable_from(bag, local, vertices) do
-    vertices = Map.put(vertices, local, true)
+  # Callbacks
 
-    Enum.reduce(out_neighbours(bag, {:local, local}), vertices, fn {local, _line}, acc ->
-      case acc do
-        %{^local => true} -> acc
-        _ -> reachable_from(bag, local, acc)
-      end
-    end)
+  def init([]) do
+    d = :digraph.new([:protected])
+    :digraph.add_vertex(d, :local)
+    :digraph.add_vertex(d, :reattach)
+    {:ok, d}
   end
 
-  defp get_line(meta), do: Keyword.get(meta, :line)
-
-  defp build_meta(nil), do: []
-  defp build_meta(line), do: [line: line]
-
-  ## Lightweight digraph implementation
-
-  defp put_edge(d, from, to) do
-    :ets.insert(d, {from, to})
+  def handle_call({:yank, local}, _from, d) do
+    out_vertices = :digraph.out_neighbours(d, local)
+    :digraph.del_edges(d, :digraph.out_edges(d, local))
+    {:reply, {[], out_vertices}, d}
   end
 
-  defp out_neighbour(d, from) do
-    try do
-      :ets.lookup_element(d, from, 2)
-    catch
-      :error, :badarg -> nil
+  def handle_call(:digraph, _from, d) do
+    {:reply, d, d}
+  end
+
+  @doc false
+  def handle_info(_msg, d) do
+    {:noreply, d}
+  end
+
+  def handle_cast({:add_local, from, to}, d) do
+    handle_add_local(d, from, to)
+    {:noreply, d}
+  end
+
+  def handle_cast({:add_import, function, module, {name, arity}}, d) do
+    handle_import(d, function, module, name, arity)
+    {:noreply, d}
+  end
+
+  def handle_cast({:add_definition, kind, tuple}, d) do
+    handle_add_definition(d, kind, tuple)
+    {:noreply, d}
+  end
+
+  def handle_cast({:add_defaults, kind, {name, arity}, defaults}, d) do
+    for i <- :lists.seq(arity - defaults, arity - 1) do
+      handle_add_definition(d, kind, {name, i})
+      handle_add_local(d, {name, i}, {name, arity})
     end
+    {:noreply, d}
   end
 
-  defp out_neighbours(d, from) do
-    try do
-      :ets.lookup_element(d, from, 2)
-    catch
-      :error, :badarg -> []
+  def handle_cast({:reattach, tuple, kind, function, {in_neigh, out_neigh}}, d) do
+    # Reattach the old function
+    for from <- in_neigh do
+      :digraph.add_vertex(d, from)
+      replace_edge!(d, from, function)
     end
+
+    for to <- out_neigh do
+      :digraph.add_vertex(d, to)
+      replace_edge!(d, function, to)
+    end
+
+    # Add the new definition
+    handle_add_definition(d, kind, tuple)
+
+    # Make a call from the old function to the new one
+    if function != tuple do
+      handle_add_local(d, function, tuple)
+    end
+
+    # Finally marked the new one as reattached
+    replace_edge!(d, :reattach, tuple)
+
+    {:noreply, d}
   end
 
-  defp take_out_neighbours(d, from) do
-    Keyword.values(:ets.take(d, from))
+  def handle_cast(:stop, d) do
+    {:stop, :normal, d}
+  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

lib/elixir/lib/node.ex

@@ -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 +87,11 @@ 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).
+  
+  For monitoring status changes of all nodes, see
+  [`:net_kernel.monitor_nodes/3`](http://www.erlang.org/doc/man/net_kernel.html#monitor_nodes-2).
   """
   @spec monitor(t, boolean) :: true
   def monitor(node, flag) do
@@ -102,9 +102,11 @@ 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).
+  
+  For monitoring status changes of all nodes, see
+  [`:net_kernel.monitor_nodes/3`](http://www.erlang.org/doc/man/net_kernel.html#monitor_nodes-2).
   """
   @spec monitor(t, boolean, [:allow_passive_connect]) :: true
   def monitor(node, flag, options) do
@@ -135,7 +137,8 @@ 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 +151,8 @@ 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
+  [`:net_kernel.connect_node/1`](http://www.erlang.org/doc/man/net_kernel.html#connect_node-1).
   """
   @spec connect(t) :: boolean | :ignored
   def connect(node) do
@@ -159,7 +163,8 @@ defmodule Node do
   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.
   """
@@ -174,11 +179,12 @@ defmodule Node do
 
   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
@@ -189,7 +195,8 @@ defmodule Node do
 
   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.
   """
@@ -204,11 +211,12 @@ defmodule Node do
 
   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
@@ -250,7 +258,7 @@ 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
 

lib/elixir/lib/option_parser.ex

@@ -1,28 +1,11 @@
 defmodule OptionParser do
   @moduledoc """
-  Functions for parsing command line options.
-
-  The main function in this module is `parse/2`, which allows
-  developers to parse a list of arguments into options:
-
-      iex> OptionParser.parse(["--debug"], strict: [debug: :boolean])
-      {[debug: true], [], []}
-
-  `OptionParser` provides some conveniences out of the box,
-  such as aliases and automatic handling of negation switches.
-
-  The `parse_head/2` function is an alternative to `parse/2`
-  which stops parsing as soon as it finds a value that is not
-  a switch nor a value for a previous switch.
-
-  This module also provides low-level functions, such as `next/2`,
-  for parsing switches manually, as well as `split/1` and `to_argv/1`
-  for parsing from and converting switches to strings.
+  This module contains functions to parse command line options.
   """
 
-  @type argv :: [String.t()]
-  @type parsed :: keyword
-  @type errors :: [{String.t(), String.t() | nil}]
+  @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
@@ -51,16 +34,14 @@ defmodule OptionParser do
 
   When parsing, it is common to list switches and their expected types:
 
-      iex> OptionParser.parse(["--debug"], strict: [debug: :boolean])
+      iex> OptionParser.parse(["--debug"], switches: [debug: :boolean])
       {[debug: true], [], []}
 
-      iex> OptionParser.parse(["--source", "lib"], strict: [source: :string])
+      iex> OptionParser.parse(["--source", "lib"], switches: [source: :string])
       {[source: "lib"], [], []}
 
-      iex> OptionParser.parse(
-      ...>   ["--source-path", "lib", "test/enum_test.exs", "--verbose"],
-      ...>   strict: [source_path: :string, verbose: :boolean]
-      ...> )
+      iex> OptionParser.parse(["--source-path", "lib", "test/enum_test.exs", "--verbose"],
+      ...>                    switches: [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.
@@ -70,23 +51,24 @@ defmodule OptionParser do
   The following options are supported:
 
     * `:switches` or `:strict` - see the "Switch definitions" section below
-    * `:allow_nonexistent_atoms` - see the "Parsing unknown switches" section below
+    * `:allow_nonexistent_atoms` - see the "Parsing dynamic 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.
+    * `:strict` - defines strict switches. Any switch in `argv` that is not
+      specified in the list is returned in the invalid options list.
 
-  Both these options accept a keyword list where the key is an atom
-  defining the name of the switch and value is the `type` of the
-  switch (see the "Types" section below for more information).
+  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.
+  Note that you should only supply the `:switches` or the`:strict` option.
   If you supply both, an `ArgumentError` exception will be raised.
 
   ### Types
@@ -128,52 +110,51 @@ defmodule OptionParser do
       iex> OptionParser.parse(["--no-op", "path/to/file"], switches: [op: :boolean])
       {[op: false], ["path/to/file"], []}
 
-  ### Parsing unknown switches
+  ### Parsing dynamic switches
 
-  When the `:switches` option is given, `OptionParser` will attempt to parse
-  unknown switches:
+  `OptionParser` also includes a dynamic mode where it will attempt to parse
+  switches dynamically. Such can be done by not specifying the `:switches` or
+  `:strict` option.
 
-      iex> OptionParser.parse(["--debug"], switches: [key: :string])
+      iex> OptionParser.parse(["--debug"])
       {[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.
+  without an argument, like `--debug` in the examples above, will automatically be
+  set to `true`.
 
-  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:
+  Since Elixir converts switches to atoms, the dynamic mode will only parse
+  switches that translate to atoms used by the runtime. Therefore, the code below
+  likely won't parse the given option since the `:option_parser_example` atom is
+  never used anywhere:
 
-      OptionParser.parse(["--option-parser-example"], switches: [debug: :boolean])
+      OptionParser.parse(["--option-parser-example"])
       # 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**:
+  However, the code below does since the `:option_parser_example` atom is used
+  at some point later (or earlier) on:
 
-      {opts, _, _} = OptionParser.parse(["--option-parser-example"], switches: [debug: :boolean])
+      {opts, _, _} = OptionParser.parse(["--option-parser-example"])
       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.
+  In other words, when using dynamic mode, 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.
+  Such option is useful when you are building command-line applications that
+  receive dynamically-named arguments but must be used with care on long-running
+  systems.
+
+  Switches followed by a value will be assigned the value, as a string.
+  Switches without an argument, like `--debug` in the examples above, will
+  automatically be set to `true`.
 
   ## Aliases
 
   A set of aliases can be specified in the `:aliases` option:
 
-      iex> OptionParser.parse(["-d"], aliases: [d: :debug], strict: [debug: :boolean])
+      iex> OptionParser.parse(["-d"], aliases: [d: :debug])
       {[debug: true], [], []}
 
   ## Examples
@@ -183,10 +164,8 @@ defmodule OptionParser do
       iex> OptionParser.parse(["--unlock", "path/to/file"], strict: [unlock: :boolean])
       {[unlock: true], ["path/to/file"], []}
 
-      iex> OptionParser.parse(
-      ...>   ["--unlock", "--limit", "0", "path/to/file"],
-      ...>   strict: [unlock: :boolean, limit: :integer]
-      ...> )
+      iex> OptionParser.parse(["--unlock", "--limit", "0", "path/to/file"],
+      ...>                    strict: [unlock: :boolean, limit: :integer])
       {[unlock: true, limit: 0], ["path/to/file"], []}
 
       iex> OptionParser.parse(["--limit", "3"], strict: [limit: :integer])
@@ -204,16 +183,11 @@ defmodule OptionParser do
       iex> OptionParser.parse(["--unknown", "xyz"], strict: [])
       {[], ["xyz"], [{"--unknown", nil}]}
 
-      iex> OptionParser.parse(
-      ...>   ["--limit", "3", "--unknown", "xyz"],
-      ...>   switches: [limit: :integer]
-      ...> )
+      iex> OptionParser.parse(["--limit", "3", "--unknown", "xyz"],
+      ...>                    switches: [limit: :integer])
       {[limit: 3, unknown: "xyz"], [], []}
 
-      iex> OptionParser.parse(
-      ...>   ["--unlock", "path/to/file", "--unlock", "path/to/another/file"],
-      ...>   strict: [unlock: :keep]
-      ...> )
+      iex> OptionParser.parse(["--unlock", "path/to/file", "--unlock", "path/to/another/file"], strict: [unlock: :keep])
       {[unlock: "path/to/file", unlock: "path/to/another/file"], [], []}
 
   """
@@ -244,17 +218,14 @@ defmodule OptionParser do
       ** (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]
-      ...> )
+      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}
+  @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}
@@ -270,16 +241,12 @@ 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"],
+      ...>                         switches: [source: :string, verbose: :boolean])
       {[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"],
+      ...>                         switches: [source: :string, verbose: :boolean, unlock: :boolean])
       {[verbose: true, source: "lib"], ["test/enum_test.exs", "--unlock"], []}
 
   """
@@ -299,29 +266,22 @@ defmodule OptionParser do
 
   ## Examples
 
-      iex> OptionParser.parse_head!(
-      ...>   ["--source", "lib", "path/to/file", "--verbose"],
-      ...>   switches: [source: :string, verbose: :boolean]
-      ...> )
+      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]
-      ...> )
+      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]
-      ...> )
+      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}
+  @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}
@@ -337,7 +297,7 @@ defmodule OptionParser do
     case next_with_config(argv, config) do
       {:ok, option, value, rest} ->
         # the option exists and it was successfully parsed
-        kinds = List.wrap(Keyword.get(switches, option))
+        kinds = List.wrap Keyword.get(switches, option)
         new_opts = store_option(opts, option, value, kinds)
         do_parse(rest, config, new_opts, args, invalid, all?)
 
@@ -346,8 +306,8 @@ defmodule OptionParser do
         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]} ->
         {Enum.reverse(opts), Enum.reverse(args, rest), Enum.reverse(invalid)}
@@ -376,16 +336,16 @@ defmodule OptionParser do
       (returned when the value cannot be parsed according to the switch type)
 
     * `{:undefined, key, value, rest}` - the option `key` is undefined
-      (returned in strict mode when the switch is unknown or on nonexistent atoms)
+      (returned in strict mode when the switch is unknown)
 
     * `{:error, rest}` - there are no switches at the head 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))
@@ -410,45 +370,34 @@ defmodule OptionParser do
   # Handles --foo or --foo=bar
   defp next_with_config(["--" <> option | rest], config) do
     {option, value} = split_option(option)
-
-    if String.contains?(option, ["_"]) do
-      {:undefined, "--" <> option, value, rest}
-    else
-      tagged = tag_option(option, config)
-      next_tagged(tagged, value, "--" <> option, rest, config)
-    end
+    tagged = tag_option(option, config)
+    next_tagged(tagged, value, "--" <> option, rest, config)
   end
 
   # Handles -a, -abc, -abc=something
   defp next_with_config(["-" <> option | rest] = argv, config) do
-    %{allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
+    %{aliases: aliases, 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) == [] ->
+      String.length(option) > 1 ->
+        key = get_option_key(option, allow_nonexistent_atoms?)
+        option_key = aliases[key]
+        if key && option_key do
+          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(option, value) ++ rest, config)
+        end
+      true ->
         # 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
 
@@ -456,21 +405,15 @@ defmodule OptionParser 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
+  defp next_tagged(tagged, value, original, rest, %{switches: switches, strict?: strict?}) do
+    if strict? and not option_defined?(tagged, switches) do
       {:undefined, original, value, rest}
     else
-      {kinds, value} = normalize_tag(tag, option, value, switches)
-      {value, kinds, rest} = normalize_value(value, kinds, rest)
-
+      {option, 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}
+        :invalid         -> {:invalid, original, value, rest}
       end
     end
   end
@@ -485,17 +428,17 @@ defmodule OptionParser do
 
   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.
+  correctly with the `switches` information in hand.
 
   ## 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
-  types:
+  flag:
 
       iex> OptionParser.to_argv([number: 2], switches: [])
       ["--number", "2"]
@@ -503,13 +446,12 @@ defmodule OptionParser do
       ["--number", "--number"]
 
   """
-  @spec to_argv(Enumerable.t(), options) :: argv
-  def to_argv(enum, options \\ []) do
-    switches = Keyword.get(options, :switches, [])
-
+  @spec to_argv(Enumerable.t, options) :: argv
+  def to_argv(enum, opts \\ []) do
+    switches = Keyword.get(opts, :switches, [])
     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)
     end)
@@ -542,7 +484,7 @@ defmodule OptionParser do
       ["foo", "bar baz"]
 
   """
-  @spec split(String.t()) :: argv
+  @spec split(String.t) :: argv
   def split(string) when is_binary(string) do
     do_split(String.trim_leading(string, " "), "", [], nil)
   end
@@ -556,7 +498,8 @@ 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, ?', ?"],
@@ -572,9 +515,11 @@ 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
@@ -584,22 +529,16 @@ defmodule OptionParser do
   ## Helpers
 
   defp build_config(opts) do
-    {switches, strict?} =
-      cond do
-        opts[:switches] && opts[:strict] ->
-          raise ArgumentError, ":switches and :strict cannot be given together"
-
-        switches = opts[:switches] ->
-          {switches, false}
-
-        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
+    {switches, strict?} = cond do
+      opts[:switches] && opts[:strict] ->
+        raise ArgumentError, ":switches and :strict cannot be given together"
+      switches = opts[:switches] ->
+        {switches, false}
+      strict = opts[:strict] ->
+        {strict, true}
+      true ->
+        {[], false}
+    end
 
     %{
       aliases: opts[:aliases] || [],
@@ -614,32 +553,27 @@ defmodule OptionParser do
       cond do
         :invalid in kinds ->
           {true, value}
-
         :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}
+            1 -> {false, value}
             _ -> {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
@@ -654,35 +588,26 @@ defmodule OptionParser do
   defp store_option(dict, option, value, kinds) do
     cond do
       :count in kinds ->
-        Keyword.update(dict, option, value, &(&1 + 1))
-
+        Keyword.update(dict, option, value, & &1 + 1)
       :keep in kinds ->
         [{option, value} | dict]
-
       true ->
         [{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
-
+  defp tag_option("no-" <> option = original, %{switches: switches, allow_nonexistent_atoms?: allow_nonexistent_atoms?}) do
     cond do
-      (negated = get_option_key(option, allow_nonexistent_atoms?)) &&
-          :boolean in List.wrap(switches[negated]) ->
+      (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
   end
 
-  defp tag_option(option, config) do
-    %{allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-
+  defp tag_option(option, %{allow_nonexistent_atoms?: allow_nonexistent_atoms?}) do
     if option_key = get_option_key(option, allow_nonexistent_atoms?) do
       {:default, option_key}
     else
@@ -690,9 +615,7 @@ defmodule OptionParser do
     end
   end
 
-  defp tag_oneletter_alias(alias, config) when is_binary(alias) do
-    %{aliases: aliases, allow_nonexistent_atoms?: allow_nonexistent_atoms?} = config
-
+  defp tag_oneletter_alias(alias, %{aliases: aliases, allow_nonexistent_atoms?: allow_nonexistent_atoms?}) when is_binary(alias) do
     if option_key = aliases[to_existing_key(alias, allow_nonexistent_atoms?)] do
       {:default, option_key}
     else
@@ -700,77 +623,97 @@ defmodule OptionParser do
     end
   end
 
-  defp expand_multiletter_alias(letters, value) do
+  defp expand_multiletter_alias(letters, value) when is_binary(letters) do
     {last, expanded} =
       letters
+      |> String.codepoints()
       |> Enum.map(&("-" <> &1))
       |> List.pop_at(-1)
-
     expanded ++ [last <> if(value, do: "=" <> value, else: "")]
   end
 
-  defp normalize_tag(:negated, option, value, switches) do
+  defp option_defined?(:unknown, _switches) do
+    false
+  end
+
+  defp option_defined?({:negated, option}, switches) do
+    Keyword.has_key?(switches, option)
+  end
+
+  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
     cond do
       :boolean in kinds ->
         {true, kinds, t}
-
       :count in kinds ->
-        {nil, kinds, t}
-
+        {1, kinds, t}
       value_in_tail?(t) ->
         [h | t] = t
         {h, kinds, t}
-
+      kinds == [] and strict? ->
+        {nil, kinds, t}
       kinds == [] ->
         {true, kinds, t}
-
       true ->
         {nil, [:invalid], t}
     end
   end
 
-  defp normalize_value(value, kinds, t) do
+  defp normalize_value(value, kinds, t, _strict?) do
     {value, kinds, t}
   end
 
-  defp value_in_tail?(["-" | _]), do: true
-  defp value_in_tail?(["- " <> _ | _]), do: true
+  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: 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(<<>>, acc), do: acc
+  defp to_underscore(option),
+    do: to_underscore(option, <<>>)
+  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?)
+    if string = to_underscore(option) do
+      to_existing_key(string, allow_nonexistent_atoms?)
+    end
   end
 
-  defp to_existing_key(option, true), do: String.to_atom(option)
-
+  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)
@@ -787,7 +730,6 @@ defmodule OptionParser 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
@@ -802,7 +744,7 @@ defmodule OptionParser do
 
   defp format_error({option, value}, opts, types) do
     type = get_type(option, opts, types)
-    "#{option} : Expected type #{type}, got #{inspect(value)}"
+    "#{option} : Expected type #{type}, got #{inspect value}"
   end
 
   defp get_type(option, opts, types) do

lib/elixir/lib/path.ex

@@ -12,7 +12,7 @@ defmodule Path do
   that require it (like `wildcard/2` and `expand/1`).
   """
 
-  @type t :: IO.chardata()
+  @type t :: :unicode.chardata()
 
   @doc """
   Converts the given path to an absolute one. Unlike
@@ -30,16 +30,15 @@ defmodule Path do
 
   ### Windows
 
-      Path.absname("foo")
+      Path.absname("foo").
       #=> "D:/usr/local/foo"
-
-      Path.absname("../x")
+      Path.absname("../x").
       #=> "D:/usr/local/../x"
 
   """
   @spec absname(t) :: binary
   def absname(path) do
-    absname(path, File.cwd!())
+    absname(path, System.cwd!)
   end
 
   @doc """
@@ -63,14 +62,9 @@ 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)
@@ -78,7 +72,8 @@ 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),
@@ -88,56 +83,49 @@ defmodule Path 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
+  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(<<?\\, 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 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_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)
 
   @doc """
   Converts the path to an absolute one and expands
@@ -151,7 +139,7 @@ defmodule Path do
   """
   @spec expand(t) :: binary
   def expand(path) do
-    expand_dot(absname(expand_home(path), File.cwd!()))
+    expand_dot absname(expand_home(path), System.cwd!)
   end
 
   @doc """
@@ -172,15 +160,14 @@ defmodule Path do
       #=> "/quux/baz/foo/bar"
 
       Path.expand("foo/bar/../bar", "/baz")
-      #=> "/baz/foo/bar"
-
+      "/baz/foo/bar"
       Path.expand("/foo/bar/../bar", "/baz")
-      #=> "/foo/bar"
+      "/foo/bar"
 
   """
   @spec expand(t, t) :: binary
   def expand(path, relative_to) do
-    expand_dot(absname(absname(expand_home(path), expand_home(relative_to)), File.cwd!()))
+    expand_dot absname(absname(expand_home(path), expand_home(relative_to)), System.cwd!)
   end
 
   @doc """
@@ -238,53 +225,54 @@ 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(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}
 
   @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(<<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(<<_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([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([_letter, ?: | relative]),
+    do: {:volumerelative, relative}
+  defp win32_pathtype(relative),
+    do: {:relative, relative}
 
   @doc """
   Returns the given `path` relative to the given `from` path.
@@ -336,7 +324,7 @@ defmodule Path do
   """
   @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
@@ -480,8 +468,10 @@ defmodule Path do
 
   """
   @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)
+  def join([name1, name2 | rest]), do:
+    join([join(name1, name2) | rest])
+  def join([name]), do:
+    IO.chardata_to_string(name)
 
   @doc """
   Joins two paths.
@@ -497,35 +487,22 @@ defmodule Path do
       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)
   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(left, right, os_type),
-    do: remove_dir_sep(left, os_type) <> "/" <> 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_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
     last = :binary.last(bin)
-
     if last == ?/ or (last == ?\\ and os_type == :win32) do
       binary_part(bin, 0, byte_size(bin) - 1)
     else
@@ -574,7 +551,6 @@ defmodule Path do
       case call({:list_dir, dir}) do
         {:ok, files} ->
           {:ok, for(file <- files, hd(file) != ?., do: file)}
-
         other ->
           other
       end
@@ -594,23 +570,24 @@ defmodule Path do
   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.
 
-    * `{item1,item2,...}` - matches one of the alternatives.
+    * `{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.
 
@@ -618,19 +595,8 @@ defmodule Path do
   exactly the same character in the same position will match. Note
   that matching is case-sensitive: `"a"` will not match `"A"`.
 
-  Directory separators must always be written as `/`, even on Windows.
-  You may call `Path.expand/1` to normalize the path before invoking
-  this function.
-
   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
 
@@ -648,7 +614,6 @@ defmodule Path do
   @spec wildcard(t, keyword) :: [binary]
   def wildcard(glob, opts \\ []) do
     mod = if Keyword.get(opts, :match_dot), do: :file, else: Path.Wildcard
-
     glob
     |> chardata_to_list!()
     |> :filelib.wildcard(mod)
@@ -659,8 +624,7 @@ defmodule Path 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)}"
+          raise ArgumentError, "cannot execute Path.wildcard/2 for path with null byte, got: #{inspect chardata}"
         else
           result
         end
@@ -676,42 +640,48 @@ 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
       {"\\" <> _, :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

lib/elixir/lib/port.ex

@@ -8,12 +8,12 @@ defmodule Port do
   ## Example
 
       iex> port = Port.open({:spawn, "cat"}, [:binary])
-      iex> send(port, {self(), {:command, "hello"}})
-      iex> send(port, {self(), {:command, "world"}})
+      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})
+      iex> send port, {self(), :close}
       :ok
       iex> flush()
       {#Port<0.1464>, :closed}
@@ -84,16 +84,16 @@ defmodule Port do
   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> port = Port.open({:spawn, "echo oops"}, [:binary])
       iex> flush()
-      {#Port<0.1444>, {:data, "hello\n"}}
+      {#Port<0.1444>, {:data, "oops\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`.
+  most times it is preferrable to execute `:spawn_executable`.
 
   ### spawn_executable
 
@@ -110,6 +110,14 @@ defmodule Port do
   the `:args` option as done above. For the full list of options, see the
   documentation for the Erlang function `:erlang.open_port/2`.
 
+  ### spawn_driver
+
+  Spawn driver is used to start Port Drivers, which are programs written in
+  C that implements a specific communication protocols and are dynamically
+  linked to the Erlang VM. Port drivers are an advanced topic and one of the
+  mechanisms for integrating C code, alongside NIFs. For more information,
+  [please check the Erlang docs](http://erlang.org/doc/reference_manual/ports.html).
+
   ### fd
 
   The `:fd` name option allows developers to access `in` and `out` file
@@ -117,7 +125,7 @@ defmodule Port do
   reimplementing core part of the Runtime System, such as the `:user` and
   `:shell` processes.
 
-  ## Zombie OS processes
+  ## Zombie 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
@@ -127,39 +135,35 @@ defmodule Port do
   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 third-party software terminates. In those cases,
+  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:
+  script in bash:
 
-      #!/bin/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"]
-      )
+      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"]
-      )
+      Port.open({:spawn_executable, "/path/to/wrapper"},
+                [args: ["/path/to/program", "a", "b", "c"]])
 
   """
 
-  @type name ::
-          {:spawn, charlist | binary}
-          | {:spawn_driver, charlist | binary}
-          | {:spawn_executable, charlist | atom}
-          | {:fd, non_neg_integer, non_neg_integer}
+  @type name :: {:spawn, charlist | binary} |
+                {:spawn_driver, charlist | binary} |
+                {:spawn_executable, charlist | atom} |
+                {:fd, non_neg_integer, non_neg_integer}
 
   @doc """
   Opens a port given a tuple `name` and a list of `options`.
@@ -176,19 +180,20 @@ defmodule Port do
     * `{:fd, fd_in, fd_out}` - accesses file descriptors, `fd_in` and `fd_out`
       opened by the VM.
 
-  For more information and the list of options, see `:erlang.open_port/2`.
+  For more information and the list of options, 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.
   """
@@ -200,7 +205,7 @@ 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.
   """
@@ -212,7 +217,7 @@ 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.
   """
@@ -224,72 +229,31 @@ defmodule Port do
   @doc """
   Returns information about the `port` or `nil` if the port is closed.
 
-  For more information, see `:erlang.port_info/1`.
+  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))
+    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`.
+  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.
-
-  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 information.
-
-  Inlined by the compiler.
-  """
-  @doc since: "1.6.0"
-  @spec monitor(port | {name, node} | name) :: reference when name: atom
-  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 information.
-
-  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.
 
@@ -297,10 +261,10 @@ defmodule Port do
   """
   @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

lib/elixir/lib/process.ex

@@ -12,29 +12,16 @@ 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.
   """
 
-  @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}
-
   @doc """
-  Tells whether the given process is alive on the local node.
+  Tells whether the given process is alive.
 
   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 running on the local node.
 
   Inlined by the compiler.
   """
@@ -52,23 +39,14 @@ defmodule Process do
   @doc """
   Returns the value for the given `key` in the process dictionary,
   or `default` if `key` is not set.
-
-  ## Examples
-
-      # Assuming :locale was not set
-      iex> Process.get(:locale, "pt")
-      "pt"
-      iex> Process.put(:locale, "fr")
-      nil
-      iex> Process.get(:locale, "pt")
-      "fr"
-
   """
   @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
 
@@ -76,17 +54,6 @@ defmodule Process do
   Returns all keys in the process dictionary.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      # Assuming :locale was not set
-      iex> :locale in Process.get_keys()
-      false
-      iex> Process.put(:locale, "pt")
-      nil
-      iex> :locale in Process.get_keys()
-      true
-
   """
   @spec get_keys() :: [term]
   defdelegate get_keys(), to: :erlang
@@ -103,20 +70,20 @@ defmodule Process do
   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 it.
+  under `key`, or `nil` in case no value was stored under `key`.
 
   ## Examples
 
       # Assuming :locale was not set
-      iex> Process.put(:locale, "en")
-      nil
-      iex> Process.put(:locale, "fr")
-      "en"
+      Process.put(:locale, "en")
+      #=> nil
+      Process.put(:locale, "fr")
+      #=> "en"
 
   """
   @spec put(term, term) :: term | nil
   def put(key, value) do
-    nillify(:erlang.put(key, value))
+    nillify :erlang.put(key, value)
   end
 
   @doc """
@@ -127,16 +94,16 @@ defmodule Process do
 
   ## Examples
 
-      iex> Process.put(:comments, ["comment", "other comment"])
-      iex> Process.delete(:comments)
-      ["comment", "other comment"]
-      iex> Process.delete(:comments)
-      nil
+      Process.put(:comments, ["comment", "other comment"])
+      Process.delete(:comments)
+      #=> ["comment", "other comment"]
+      Process.delete(:comments)
+      #=> nil
 
   """
   @spec delete(term) :: term | nil
   def delete(key) do
-    nillify(:erlang.erase(key))
+    nillify :erlang.erase(key)
   end
 
   @doc """
@@ -191,10 +158,10 @@ defmodule Process do
 
   In other words, **do not**:
 
-      Task.start_link(fn ->
+      Task.start_link fn ->
         do_something()
         ...
-      end)
+      end
 
       # Wait until work is done
       Process.sleep(2000)
@@ -202,18 +169,16 @@ defmodule Process do
   But **do**:
 
       parent = self()
-
-      Task.start_link(fn ->
+      Task.start_link fn ->
         do_something()
-        send(parent, :work_is_done)
+        send parent, :work_is_done
         ...
-      end)
+      end
 
       receive do
         :work_is_done -> :ok
       after
-        # Optional timeout
-        30_000 -> :timeout
+        30_000 -> :timeout # Optional timeout
       end
 
   For cases like the one above, `Task.async/1` and `Task.await/2` are
@@ -222,9 +187,9 @@ defmodule Process do
   Similarly, if you are waiting for a process to terminate,
   monitor that process instead of sleeping. **Do not**:
 
-      Task.start_link(fn ->
+      Task.start_link fn ->
         ...
-      end)
+      end
 
       # Wait until task terminates
       Process.sleep(2000)
@@ -232,17 +197,15 @@ defmodule Process do
   Instead **do**:
 
       {:ok, pid} =
-        Task.start_link(fn ->
+        Task.start_link fn ->
           ...
-        end)
+        end
 
       ref = Process.monitor(pid)
-
       receive do
         {:DOWN, ^ref, _, _, _} -> :task_is_down
       after
-        # Optional timeout
-        30_000 -> :timeout
+        30_000 -> :timeout # Optional timeout
       end
 
   """
@@ -254,13 +217,7 @@ defmodule Process do
   end
 
   @doc """
-  Sends a message to the given `dest`.
-
-  `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.
-
-  Inlined by the compiler.
+  Sends a message to the given process.
 
   ## Options
 
@@ -278,9 +235,10 @@ defmodule Process do
       iex> Process.send({:name, :node_that_does_not_exist}, :hi, [:noconnect])
       :noconnect
 
+  Inlined by the compiler.
   """
   @spec send(dest, msg, [option]) :: :ok | :noconnect | :nosuspend
-        when dest: dest(),
+        when dest: pid | port | atom | {atom, node},
              msg: any,
              option: :noconnect | :nosuspend
   defdelegate send(dest, msg, options), to: :erlang
@@ -293,9 +251,6 @@ defmodule Process do
   which is looked up at the time of delivery. No error is produced if the name does
   not refer to a process.
 
-  The message is not sent immediately. Therefore, `dest` can receive other messages
-  in-between even when `time` is `0`.
-
   This function returns a timer reference, which can be read with `read_timer/1`
   or canceled with `cancel_timer/1`.
 
@@ -338,8 +293,6 @@ defmodule Process do
   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.
 
-  Inlined by the compiler.
-
   ## Options
 
     * `:async` - (boolean) when `false`, the request for cancellation is
@@ -357,6 +310,7 @@ defmodule Process do
       cancellation has been performed. If `:async` is `true` and `:info` is
       `false`, no message is sent. Defaults to `true`.
 
+  Inlined by the compiler.
   """
   @spec cancel_timer(reference, options) :: non_neg_integer | false | :ok
         when options: [async: boolean, info: boolean]
@@ -380,13 +334,10 @@ defmodule Process do
   @spec read_timer(reference) :: non_neg_integer | false
   defdelegate read_timer(timer_ref), to: :erlang
 
-  @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 """
@@ -398,17 +349,9 @@ defmodule Process do
   just the spawned process PID.
 
   More options are available; for the comprehensive 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.
-
-  ## Examples
-
-      Process.spawn(fn -> 1 + 2 end, [:monitor])
-      #=> {#PID<0.93.0>, #Reference<0.18808174.1939079169.202418>}
-      Process.spawn(fn -> 1 + 2 end, [:link])
-      #=> #PID<0.95.0>
-
   """
   @spec spawn((() -> any), spawn_opts) :: pid | {pid, reference}
   defdelegate spawn(fun, opts), to: :erlang, as: :spawn_opt
@@ -423,7 +366,7 @@ defmodule Process do
   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.
   """
@@ -445,51 +388,27 @@ defmodule Process do
       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.
-
-  See [the need for monitoring](https://elixir-lang.org/getting-started/mix-otp/genserver.html#the-need-for-monitoring)
-  for an example. See `:erlang.monitor/2` for more information.
+  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`](http://www.erlang.org/doc/man/erlang.html#monitor-2) for more info.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      pid = spawn(fn -> 1 + 2 end)
-      #=> #PID<0.118.0>
-      Process.monitor(pid)
-      #=> #Reference<0.906660723.3006791681.40191>
-      Process.exit(pid, :kill)
-      #=> true
-      receive do
-        msg -> msg
-      end
-      #=> {:DOWN, #Reference<0.906660723.3006791681.40191>, :process, #PID<0.118.0>, :noproc}
-
   """
-  @spec monitor(pid | {name, node} | name) :: reference when name: atom
+  @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`.
+  Demonitors the monitor identifies 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 information.
+  See [`:erlang.demonitor/2`](http://www.erlang.org/doc/man/erlang.html#demonitor-2) for more info.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      pid = spawn(fn -> 1 + 2 end)
-      ref = Process.monitor(pid)
-      Process.demonitor(ref)
-      #=> true
-
   """
   @spec demonitor(reference, options :: [:flush | :info]) :: boolean
   defdelegate demonitor(monitor_ref, options \\ []), to: :erlang
@@ -502,15 +421,9 @@ defmodule Process do
   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.
 
-  See `:erlang.processes/0` for more information.
+  See [`:erlang.processes/0`](http://www.erlang.org/doc/man/erlang.html#processes-0) for more info.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      Process.list()
-      #=> [#PID<0.0.0>, #PID<0.1.0>, #PID<0.2.0>, #PID<0.3.0>, ...]
-
   """
   @spec list() :: [pid]
   defdelegate list(), to: :erlang, as: :processes
@@ -533,7 +446,7 @@ defmodule Process do
   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 information.
+  See [`:erlang.link/1`](http://www.erlang.org/doc/man/erlang.html#link-1) for more info.
 
   Inlined by the compiler.
   """
@@ -541,6 +454,7 @@ defmodule Process do
   defdelegate link(pid_or_port), to: :erlang
 
   @doc """
+
   Removes the link between the calling process and the given item (process or
   port).
 
@@ -549,7 +463,7 @@ defmodule Process do
 
   The return value of this function is always `true`.
 
-  See `:erlang.unlink/1` for more information.
+  See [`:erlang.unlink/1`](http://www.erlang.org/doc/man/erlang.html#unlink-1) for more info.
 
   Inlined by the compiler.
   """
@@ -576,34 +490,24 @@ defmodule Process do
     * `true`
     * `:undefined`
 
-  ## Examples
-
-      Process.register(self(), :test)
-      #=> true
-      send(:test, :hello)
-      #=> :hello
-      send(:wrong_name, :hello)
-      #=> ** (ArgumentError) argument error
-
   """
   @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
+  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 when node(pid_or_port) != node()  ->
+      message = "could not register the #{pid_or_port 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])
+      message = "could not register the #{pid_or_port pid_or_port} with " <>
+                "name #{inspect name}. Or it is not alive, or the name is already " <>
+                "taken, or it has already been given another name"
+      :erlang.error ArgumentError.exception(message), [pid_or_port, name]
   end
 
+  defp pid_or_port(pid) when is_pid(pid), do: "pid #{inspect pid}"
+  defp pid_or_port(port) when is_port(port), do: "port #{inspect port}"
+
   @doc """
   Removes the registered `name`, associated with a PID
   or a port identifier.
@@ -612,16 +516,6 @@ defmodule Process do
   to any PID or port.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      Process.register(self(), :test)
-      #=> true
-      Process.unregister(:test)
-      #=> true
-      Process.unregister(:wrong_name)
-      #=> ** (ArgumentError) argument error
-
   """
   @spec unregister(atom) :: true
   defdelegate unregister(name), to: :erlang
@@ -630,32 +524,17 @@ defmodule Process do
   Returns the PID or port identifier registered under `name` or `nil` if the
   name is not registered.
 
-  See `:erlang.whereis/1` for more information.
-
-  ## Examples
-
-      Process.register(self(), :test)
-      Process.whereis(:test)
-      #=> #PID<0.84.0>
-      Process.whereis(:wrong_name)
-      #=> nil
-
+  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.
-
-  ## Examples
-
-      Process.group_leader()
-      #=> #PID<0.53.0>
-
   """
   @spec group_leader() :: pid
   defdelegate group_leader(), to: :erlang
@@ -677,20 +556,12 @@ defmodule Process do
   Returns a list of names which have been registered using `register/2`.
 
   Inlined by the compiler.
-
-  ## Examples
-
-      Process.register(self(), :test)
-      Process.registered()
-      #=> [:test, :elixir_config, :inet_db, ...]
-
   """
   @spec registered() :: [atom]
   defdelegate registered(), to: :erlang
 
-  @typep heap_size ::
-           non_neg_integer
-           | %{size: non_neg_integer, kill: boolean, error_logger: boolean}
+  @typep heap_size :: non_neg_integer |
+                      %{size: non_neg_integer, kill: boolean, error_logger: boolean}
 
   @typep priority_level :: :low | :normal | :high | :max
 
@@ -699,19 +570,21 @@ defmodule Process do
 
   Returns the old value of `flag`.
 
-  See `:erlang.process_flag/2` for more information.
+  See [`:erlang.process_flag/2`](http://www.erlang.org/doc/man/erlang.html#process_flag-2) for more info.
+
+  Note that `flag` values `:max_heap_size` and `:message_queue_data` are only available since OTP 19.
 
   Inlined by the compiler.
   """
   @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(: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(:save_calls, 0..10_000) :: 0..10_000
   @spec flag(:sensitive, boolean) :: boolean
   @spec flag(:trap_exit, boolean) :: boolean
   defdelegate flag(flag, value), to: :erlang, as: :process_flag
@@ -726,11 +599,11 @@ defmodule Process do
   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 information.
+  See [`:erlang.process_flag/3`](http://www.erlang.org/doc/man/erlang.html#process_flag-3) for more info.
 
   Inlined by the compiler.
   """
-  @spec flag(pid, :save_calls, 0..10000) :: 0..10000
+  @spec flag(pid, :save_calls, 0..10_000) :: 0..10_000
   defdelegate flag(pid, flag, value), to: :erlang, as: :process_flag
 
   @doc """
@@ -739,20 +612,20 @@ defmodule Process do
 
   Use this only for debugging information.
 
-  See `:erlang.process_info/1` for more information.
+  See [`:erlang.process_info/1`](http://www.erlang.org/doc/man/erlang.html#process_info-1) for more info.
   """
-  @spec info(pid) :: keyword | nil
+  @spec info(pid) :: keyword
   def info(pid) do
-    nillify(:erlang.process_info(pid))
+    nillify :erlang.process_info(pid)
   end
 
   @doc """
   Returns information about the process identified by `pid`,
   or returns `nil` if the process is not alive.
 
-  See `:erlang.process_info/2` for more information.
+  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
+  @spec info(pid, atom | [atom]) :: {atom, term} | [{atom, term}]  | nil
   def info(pid, spec)
 
   def info(pid, :registered_name) do
@@ -764,7 +637,7 @@ 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 """
@@ -775,7 +648,7 @@ defmodule Process do
   which is useful if the process does not expect to receive any messages
   in the near future.
 
-  See `:erlang.hibernate/3` for more information.
+  See [`:erlang.hibernate/3`](http://www.erlang.org/doc/man/erlang.html#hibernate-3) for more info.
 
   Inlined by the compiler.
   """
@@ -784,5 +657,5 @@ defmodule Process do
 
   @compile {:inline, nillify: 1}
   defp nillify(:undefined), do: nil
-  defp nillify(other), do: other
+  defp nillify(other),      do: other
 end

lib/elixir/lib/protocol.ex

@@ -19,23 +19,23 @@ 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("arg" <> Integer.to_string(pos)), __MODULE__) end
-
-    call_args = :lists.map(varify, :lists.seq(2, arity))
+    call_args = :lists.map(fn pos -> Macro.var(String.to_atom("var" <> Integer.to_string(pos)), __MODULE__) end,
+                           :lists.seq(2, arity))
     call_args = [quote(do: term) | call_args]
 
     quote do
-      name = unquote(name)
+      name  = unquote(name)
       arity = unquote(arity)
 
       @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
@@ -44,7 +44,7 @@ defmodule Protocol do
 
       # 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
@@ -58,7 +58,7 @@ defmodule Protocol do
 
   Returns `:ok` if so, otherwise raises `ArgumentError`.
   """
-  @spec assert_protocol!(module) :: :ok
+  @spec assert_protocol!(module) :: :ok | no_return
   def assert_protocol!(module) do
     assert_protocol!(module, "")
   end
@@ -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
@@ -85,7 +85,7 @@ defmodule Protocol do
 
   Returns `:ok` if so, otherwise raises `ArgumentError`.
   """
-  @spec assert_impl!(module, module) :: :ok
+  @spec assert_impl!(module, module) :: :ok | no_return
   def assert_impl!(protocol, base) do
     assert_impl!(protocol, base, "")
   end
@@ -95,80 +95,32 @@ 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
-      Protocol.__derive__([{unquote(protocol), unquote(options)}], unquote(module), __ENV__)
+      module = unquote(module)
+      Protocol.__derive__([{unquote(protocol), unquote(options)}], module, __ENV__)
     end
   end
 
@@ -185,21 +137,22 @@ defmodule Protocol do
 
   ## Examples
 
-      # Get Elixir's ebin directory path and retrieve all protocols
+      # Get Elixir's ebin and retrieve all protocols
       iex> path = :code.lib_dir(:elixir, :ebin)
       iex> mods = Protocol.extract_protocols([path])
       iex> Enumerable in mods
       true
 
   """
-  @spec extract_protocols([charlist | String.t()]) :: [atom]
+  @spec extract_protocols([charlist | 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 """
@@ -214,30 +167,30 @@ defmodule Protocol do
 
   ## Examples
 
-      # Get Elixir's ebin directory path and retrieve all protocols
+      # Get Elixir's ebin and retrieve all protocols
       iex> path = :code.lib_dir(:elixir, :ebin)
       iex> mods = Protocol.extract_impls(Enumerable, [path])
       iex> List in mods
       true
 
   """
-  @spec extract_impls(module, [charlist | String.t()]) :: [atom]
+  @spec extract_impls(module, [charlist | 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)
+    extract_matching_by_attribute paths, prefix, fn
+      _mod, attributes ->
+        case attributes[:protocol_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
@@ -259,9 +212,8 @@ defmodule Protocol do
     case :beam_lib.chunks(file, [:attributes]) do
       {:ok, {module, [attributes: attributes]}} ->
         callback.(module, attributes)
-
-      _ ->
-        nil
+       _ ->
+         nil
     end
   end
 
@@ -283,48 +235,44 @@ defmodule Protocol do
   are retrieved with the help of `extract_impls/2`.
 
   It returns the updated version of the protocol bytecode.
-  If the first element of the tuple is `:ok`, it means
-  the protocol was consolidated.
-
   A given bytecode or protocol implementation can be checked
   to be consolidated or not by analyzing the protocol
   attribute:
 
       Protocol.consolidated?(Enumerable)
 
+  If the first element of the tuple is `true`, it means
+  the protocol was consolidated.
+
   This function does not load the protocol at any point
   nor loads the new bytecode for the compiled module.
   However each implementation must be available and
   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, specs, compile_info} <- beam_protocol(protocol),
-         {:ok, definitions} <- change_debug_info(protocol, ast_info, types),
-         do: compile(definitions, specs, compile_info)
+    with {:ok, ast_info, chunks_info} <- beam_protocol(protocol),
+         {:ok, code} <- change_debug_info(ast_info, types),
+         do: compile(protocol, code, chunks_info)
   end
 
   defp beam_protocol(protocol) do
-    chunk_ids = [:debug_info, 'Docs', 'ExDp']
+    chunk_ids = [:abstract_code, :attributes, :compile_info, 'ExDc']
     opts = [:allow_missing_chunks]
-
     case :beam_lib.chunks(beam_file(protocol), chunk_ids, opts) do
-      {:ok, {^protocol, [{:debug_info, debug_info} | chunks]}} ->
-        {:debug_info_v1, _backend, {:elixir_v1, info, specs}} = debug_info
-        %{attributes: attributes, definitions: definitions} = info
-        chunks = :lists.map(fn {name, value} -> {List.to_string(name), value} end, chunks)
-
+      {:ok, {^protocol, [{:abstract_code, {_raw, abstract_code}},
+                         {:attributes, attributes},
+                         {:compile_info, compile_info},
+                         {'ExDc', docs}]}} ->
         case attributes[:protocol] do
           [fallback_to_any: any] ->
-            {:ok, {any, definitions}, specs, {info, chunks}}
-
+            {:ok, {protocol, any, abstract_code}, {compile_info, docs}}
           _ ->
             {:error, :not_a_protocol}
         end
-
       _ ->
         {:error, :no_beam_info}
     end
@@ -332,90 +280,125 @@ 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, definitions}, types) do
-    types = if any, do: types, else: List.delete(types, Any)
-    all = [Any] ++ for {_guard, mod} <- __built_in__(), do: mod
+  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
     structs = types -- all
-
-    case List.keytake(definitions, {:__protocol__, 1}, 0) do
-      {protocol_def, definitions} ->
-        {impl_for, definitions} = List.keytake(definitions, {:impl_for, 1}, 0)
-        {struct_impl_for, definitions} = List.keytake(definitions, {:struct_impl_for, 1}, 0)
-
-        protocol_def = change_protocol(protocol_def, types)
-        impl_for = change_impl_for(impl_for, protocol, types)
-        struct_impl_for = change_struct_impl_for(struct_impl_for, protocol, types, structs)
-
-        {:ok, [protocol_def, impl_for, struct_impl_for] ++ definitions}
-
-      nil ->
-        {:error, :not_a_protocol}
+    case change_impl_for(code, protocol, types, structs, false, []) do
+      {:ok, ret} -> {:ok, ret}
+      other      -> other
     end
   end
 
-  defp change_protocol({_name, _kind, meta, clauses}, types) do
-    clauses =
-      Enum.map(clauses, fn
-        {meta, [:consolidated?], [], _} -> {meta, [:consolidated?], [], true}
-        {meta, [:impls], [], _} -> {meta, [:impls], [], {:consolidated, types}}
-        clause -> clause
-      end)
+  defp change_impl_for([{:function, line, :__protocol__, 1, clauses} | tail], protocol, types, structs, _, acc) do
+    abstract_types = :erl_parse.abstract(:lists.usort(types))
 
-    {{:__protocol__, 1}, :def, meta, clauses}
+    clauses = :lists.map(fn
+      {:clause, l, [{:atom, _, :consolidated?}], [], [{:atom, _, _}]} ->
+        {:clause, l, [{:atom, 0, :consolidated?}], [], [{:atom, 0, true}]}
+      {:clause, l, [{:atom, _, :impls}], [], [{:atom, _, _}]} ->
+        {:clause, l, [{:atom, 0, :impls}], [], [{:tuple, 0, [{:atom, 0, :consolidated}, abstract_types]}]}
+      {:clause, _, _, _, _} = c ->
+        c
+    end, clauses)
+
+    change_impl_for(tail, protocol, types, structs, true,
+                    [{:function, line, :__protocol__, 1, clauses} | acc])
   end
 
-  defp change_impl_for({_name, _kind, meta, _clauses}, protocol, types) do
+  defp change_impl_for([{:function, line, :impl_for, 1, _} | tail], protocol, types, structs, protocol?, acc) do
     fallback = if Any in types, do: load_impl(protocol, Any)
-    line = meta[:line]
 
-    clauses =
-      for {guard, mod} <- __built_in__(),
-          mod in types,
-          do: built_in_clause_for(mod, guard, protocol, meta, line)
+    clauses = for {guard, mod} <- __builtin__(),
+                  mod in types,
+                  do: builtin_clause_for(mod, guard, protocol, line)
 
-    struct_clause = struct_clause_for(meta, line)
-    fallback_clause = fallback_clause_for(fallback, protocol, meta)
-    clauses = [struct_clause] ++ clauses ++ [fallback_clause]
+    clauses = [struct_clause_for(line) | clauses] ++
+              [fallback_clause_for(fallback, protocol, line)]
 
-    {{:impl_for, 1}, :def, meta, clauses}
+    change_impl_for(tail, protocol, types, structs, protocol?,
+                    [{:function, line, :impl_for, 1, clauses} | acc])
   end
 
-  defp change_struct_impl_for({_name, _kind, meta, _clauses}, protocol, types, structs) do
+  defp change_impl_for([{:function, line, :struct_impl_for, 1, _} | tail], protocol, types, structs, protocol?, acc) do
     fallback = if Any in types, do: load_impl(protocol, Any)
-    clauses = for struct <- structs, do: each_struct_clause_for(struct, protocol, meta)
-    clauses = clauses ++ [fallback_clause_for(fallback, protocol, meta)]
+    clauses = for struct <- structs, do: each_struct_clause_for(struct, protocol, line)
+    clauses = clauses ++ [fallback_clause_for(fallback, protocol, line)]
 
-    {{:struct_impl_for, 1}, :defp, meta, clauses}
+    change_impl_for(tail, protocol, types, structs, protocol?,
+                    [{:function, line, :struct_impl_for, 1, clauses} | acc])
   end
 
-  defp built_in_clause_for(mod, guard, protocol, meta, line) do
-    x = quote(line: line, do: x)
-    guard = quote(line: line, do: :erlang.unquote(guard)(unquote(x)))
-    body = load_impl(protocol, mod)
-    {meta, [x], [guard], body}
+  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?}]}, _]} ->
+          {:type, line, :fun,
+           [{:type, line, :product, [{:atom, 0, :consolidated?}]},
+            {:atom, 0, true}]}
+        {:type, line, :fun, [{:type, _, :product, [{:atom, _, :impls}]}, _]} ->
+          {:type, line, :fun,
+           [{:type, line, :product, [{:atom, 0, :impls}]},
+            {:type, 0, :tuple,
+             [{:atom, 0, :consolidated},
+              {:type, 0, :list, [{:type, 0, :module, []}]}]}]}
+        other -> other
+      end
+    end
+    change_impl_for(tail, protocol, types, structs, protocol?, [{:attribute, line, :spec, {{:__protocol__, 1}, new_specs}} | acc])
   end
 
-  defp struct_clause_for(meta, line) do
-    x = quote(line: line, do: x)
-    head = quote(line: line, do: %{__struct__: unquote(x)})
-    guard = quote(line: line, do: :erlang.is_atom(unquote(x)))
-    body = quote(line: line, do: struct_impl_for(unquote(x)))
-    {meta, [head], [guard], body}
+  defp change_impl_for([head | tail], protocol, info, types, protocol?, acc) do
+    change_impl_for(tail, protocol, info, types, protocol?, [head | acc])
   end
 
-  defp each_struct_clause_for(struct, protocol, meta) do
-    {meta, [struct], [], load_impl(protocol, struct)}
+  defp change_impl_for([], _protocol, _info, _types, protocol?, acc) do
+    if protocol? do
+      {:ok, Enum.reverse(acc)}
+    else
+      {:error, :not_a_protocol}
+    end
   end
 
-  defp fallback_clause_for(value, _protocol, meta) do
-    {meta, [quote(do: _)], [], value}
+  defp builtin_clause_for(mod, guard, protocol, line) do
+    {: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
+    {: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)}]}
+  end
+
+  defp fallback_clause_for(value, _protocol, line) do
+    {:clause, line, [{:var, line, :_}], [],
+      [{:atom, line, value}]}
   end
 
   defp load_impl(protocol, for) do
@@ -423,29 +406,28 @@ defmodule Protocol do
   end
 
   # Finally compile the module and emit its bytecode.
-  defp compile(definitions, specs, {info, chunks}) do
-    info = %{info | definitions: definitions}
-    {:ok, :elixir_erl.consolidate(info, specs, chunks)}
+  defp compile(protocol, code, {compile_info, docs}) 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,
+      case docs do
+        :missing_chunk -> binary
+        _ -> :elixir_erl.add_beam_chunks(binary, [{"ExDc", docs}])
+      end}
   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]
@@ -467,45 +449,30 @@ defmodule Protocol do
   end
 
   defp after_defprotocol do
-    quote bind_quoted: [built_in: __built_in__()] do
-      any_impl_for =
-        if @fallback_to_any do
-          quote do: unquote(__MODULE__.Any).__impl__(:target)
-        else
-          nil
-        end
-
-      # Disable dialyzer checks - before and after consolidation
-      # the types could be more strict
-      @dialyzer {:nowarn_function, __protocol__: 1, impl_for: 1, impl_for!: 1}
-
+    quote bind_quoted: [builtin: __builtin__()] do
       @doc false
       @spec impl_for(term) :: atom | nil
-      Kernel.def(impl_for(data))
+      Kernel.def impl_for(data)
 
       # Define the implementation for structs.
       #
       # It simply delegates to struct_impl_for which is then
       # optimized during protocol consolidation.
-      Kernel.def impl_for(%struct{}) do
+      Kernel.def impl_for(%{__struct__: struct}) when :erlang.is_atom(struct) do
         struct_impl_for(struct)
       end
 
       # Define the implementation for built-ins
-      :lists.foreach(
-        fn {guard, mod} ->
-          target = Module.concat(__MODULE__, mod)
+      :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,
-        built_in
-      )
+        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
@@ -514,35 +481,41 @@ defmodule Protocol do
       # 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)
+        any_impl_for()
       end
 
       @doc false
-      @spec impl_for!(term) :: atom
-      if any_impl_for do
-        Kernel.def impl_for!(data) do
-          impl_for(data)
-        end
+      @spec impl_for!(term) :: atom | no_return
+      Kernel.def impl_for!(data) do
+        impl_for(data) || raise(Protocol.UndefinedError, protocol: __MODULE__, value: 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
 
@@ -554,18 +527,18 @@ defmodule Protocol do
       @doc false
       @spec __protocol__(:module) :: __MODULE__
       @spec __protocol__(:functions) :: unquote(Protocol.__functions_spec__(@functions))
-      @spec __protocol__(:consolidated?) :: boolean
-      @spec __protocol__(:impls) :: :not_consolidated | {:consolidated, [module]}
-      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?) :: 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
     end
   end
 
   @doc false
-  def __functions_spec__([]), do: []
-
+  def __functions_spec__([]),
+    do: []
   def __functions_spec__([head | tail]),
     do: [:lists.foldl(&{:|, [], [&1, &2]}, head, tail), quote(do: ...)]
 
@@ -574,11 +547,11 @@ defmodule Protocol 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.
@@ -588,23 +561,23 @@ 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__)
 
       defmodule name do
         @behaviour protocol
-        @protocol protocol
-        @for for
+        @protocol  protocol
+        @for       for
 
         unquote(block)
 
@@ -618,38 +591,41 @@ defmodule Protocol do
 
   @doc false
   def __derive__(derives, for, %Macro.Env{} = env) when is_atom(for) do
-    struct = Macro.struct!(for, env)
+    struct =
+      if for == env.module do
+        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
+    :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__, :protocol_impl, persist: true)
             @protocol_impl [protocol: unquote(protocol), for: unquote(for)]
 
@@ -657,13 +633,11 @@ defmodule Protocol do
             @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
 
@@ -671,33 +645,43 @@ 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, pos} ->
+        if Kernel.Typespec.spec_to_signature(expr) == signature do
+          Module.store_typespec(module, :callback, {:callback, expr, pos})
+          true
+        end
+      end, specs)
+
+    :lists.any(& &1 == true, found)
+  end
+
   ## Helpers
 
   @doc false
-  def __built_in__ 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
-    ]
+  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]
   end
 end

lib/elixir/lib/range.ex

@@ -2,8 +2,8 @@ defmodule Range do
   @moduledoc """
   Defines a range.
 
-  A range represents a sequence of one or many,
-  ascending or descending, consecutive integers.
+  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
@@ -36,16 +36,13 @@ defmodule Range do
       iex> Enum.member?(range, 8)
       true
 
-  Such function calls are efficient memory-wise no matter the
-  size of the range. The implementation of the `Enumerable`
-  protocol uses logic based solely on the endpoints and does
-  not materialize the whole list of integers.
   """
 
   defstruct first: nil, last: nil
 
-  @type t :: %__MODULE__{first: integer, last: integer}
-  @type t(first, last) :: %__MODULE__{first: first, last: last}
+  @type t :: %Range{first: integer, last: integer}
+  @type t(first, last) :: %Range{first: first, last: last}
+
 
   @doc """
   Creates a new range.
@@ -57,40 +54,23 @@ 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
 
   @doc """
-  Checks if two ranges are disjoint.
+  Returns `true` if the given `term` is a valid range.
 
   ## Examples
 
-      iex> Range.disjoint?(1..5, 6..9)
+      iex> Range.range?(1..3)
       true
-      iex> Range.disjoint?(5..1, 6..9)
-      true
-      iex> Range.disjoint?(1..5, 5..9)
-      false
-      iex> Range.disjoint?(1..5, 2..7)
+
+      iex> Range.range?(0)
       false
 
   """
-  @doc since: "1.8.0"
-  @spec disjoint?(t, t) :: boolean
-  def disjoint?(first1..last1, first2..last2) do
-    {first1, last1} = normalize(first1, last1)
-    {first2, last2} = normalize(first2, last2)
-    last2 < first1 or last1 < first2
-  end
-
-  @compile inline: [normalize: 2]
-  defp normalize(first, last) when first > last, do: {last, first}
-  defp normalize(first, last), do: {first, last}
-
-  # TODO: Remove by 2.0
-  @doc false
-  @deprecated "Pattern match on first..last instead"
+  @spec range?(term) :: boolean
   def range?(term)
   def range?(first..last) when is_integer(first) and is_integer(last), do: true
   def range?(_), do: false
@@ -101,20 +81,20 @@ defimpl Enumerable, for: Range do
     reduce(first, last, acc, fun, _up? = 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, _up? = true) when x <= y do
+    reduce(x + 1, y, fun.(x, acc), fun, _up? = 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, _up? = false) when x >= y do
+    reduce(x - 1, y, fun.(x, acc), fun, _up? = false)
   end
 
   defp reduce(_, _, {:cont, acc}, _fun, _up) do
@@ -140,26 +120,12 @@ defimpl Enumerable, for: Range do
       {: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)])
+    concat [to_doc(first, opts), "..", to_doc(last, opts)]
   end
 end

lib/elixir/lib/record.ex

@@ -4,7 +4,7 @@ defmodule Record do
 
   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
@@ -28,10 +28,10 @@ defmodule Record do
 
       defmodule MyModule do
         require Record
-        Record.defrecord(:user, name: "john", age: 25)
+        Record.defrecord :user, name: "john", age: 25
 
-        @type user :: record(:user, name: String.t(), age: integer)
-        # expands to: "@type user :: {:user, String.t(), integer}"
+        @type user :: record(:user, name: String.t, age: integer)
+        # expands to: "@type user :: {:user, String.t, integer}"
       end
 
   """
@@ -54,41 +54,21 @@ defmodule Record do
       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 where those relative includes exist.
-
-    * `:macros` - (keyword list of macro names and values) if the record
-      being extracted 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.
 
   ## Examples
 
       iex> Record.extract(:file_info, from_lib: "kernel/include/file.hrl")
-      [
-        size: :undefined,
-        type: :undefined,
-        access: :undefined,
-        atime: :undefined,
-        mtime: :undefined,
-        ctime: :undefined,
-        mode: :undefined,
-        links: :undefined,
-        major_device: :undefined,
-        minor_device: :undefined,
-        inode: :undefined,
-        uid: :undefined,
-        gid: :undefined
-      ]
+      [size: :undefined, type: :undefined, access: :undefined, atime: :undefined,
+       mtime: :undefined, ctime: :undefined, mode: :undefined, links: :undefined,
+       major_device: :undefined, minor_device: :undefined, inode: :undefined,
+       uid: :undefined, gid: :undefined]
 
   """
   @spec extract(name :: atom, keyword) :: keyword
@@ -112,7 +92,6 @@ defmodule Record do
       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`
@@ -138,9 +117,21 @@ 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_atom(unquote(kind)) and is_tuple(unquote(data)) and tuple_size(unquote(data)) > 0 and
+            elem(unquote(data), 0) == unquote(kind)
+        end
+      false ->
+        quote do
+          result = unquote(data)
+          kind = unquote(kind)
+          is_atom(kind) and is_tuple(result) and tuple_size(result) > 0 and elem(result, 0) == kind
+        end
+    end
+  end
 
   @doc """
   Checks if the given `data` is a record.
@@ -157,8 +148,20 @@ 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(elem(unquote(data), 0))
+        end
+      false ->
+        quote do
+          result = unquote(data)
+          is_tuple(result) and tuple_size(result) > 0 and is_atom(elem(result, 0))
+        end
+    end
+  end
 
   @doc """
   Defines a set of macros to create, access, and pattern match
@@ -187,7 +190,7 @@ defmodule Record do
 
       defmodule User do
         require Record
-        Record.defrecord(:user, name: "meg", age: "25")
+        Record.defrecord :user, [name: "meg", age: "25"]
       end
 
   In the example above, a set of macros named `user` but with different
@@ -227,7 +230,7 @@ defmodule Record do
 
       defmodule User do
         require Record
-        Record.defrecord(:user, Customer, name: nil)
+        Record.defrecord :user, Customer, name: nil
       end
 
       require User
@@ -240,41 +243,30 @@ defmodule Record do
   a record after extracting it from an Erlang library that uses anonymous
   functions for defaults.
 
-      Record.defrecord(:my_rec, Record.extract(...))
+      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:
 
       defmodule MyRec do
         require Record
-        Record.defrecord(:my_rec, Record.extract(...) |> Keyword.merge(fun_field: &__MODULE__.foo/2))
+        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
-      defined_arity =
-        Enum.find(0..2, fn arity ->
-          Module.defines?(__MODULE__, {name, arity})
-        end)
-
-      if defined_arity do
-        raise ArgumentError,
-              "cannot define record #{inspect(name)} because a definition #{name}/#{defined_arity} already exists"
-      end
-
       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
@@ -285,25 +277,14 @@ defmodule Record do
   """
   defmacro defrecordp(name, tag \\ nil, kv) do
     quote bind_quoted: [name: name, tag: tag, kv: kv] do
-      defined_arity =
-        Enum.find(0..2, fn arity ->
-          Module.defines?(__MODULE__, {name, arity})
-        end)
-
-      if defined_arity do
-        raise ArgumentError,
-              "cannot define record #{inspect(name)} because a definition #{name}/#{defined_arity} already exists"
-      end
-
       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
@@ -312,7 +293,7 @@ defmodule Record do
   # Normalizes of record fields to have default values.
   @doc false
   def __fields__(type, fields) do
-    normalizer_fun = fn
+    :lists.map(fn
       {key, value} when is_atom(key) ->
         try do
           Macro.escape(value)
@@ -322,15 +303,11 @@ defmodule Record do
         else
           value -> {key, value}
         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.
@@ -339,23 +316,18 @@ defmodule Record do
     cond do
       is_atom(args) ->
         index(tag, fields, args)
-
       Keyword.keyword?(args) ->
         create(tag, 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})
-
           _ ->
-            quote(do: Record.__keyword__(unquote(tag), unquote(fields), unquote(args)))
+            quote do: Record.__keyword__(unquote(tag), unquote(fields), unquote(args))
         end
     end
   end
@@ -366,43 +338,46 @@ defmodule Record do
     cond do
       is_atom(args) ->
         get(tag, fields, record, args)
-
       Keyword.keyword?(args) ->
         update(tag, 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 a keyword list, got: #{Macro.to_string args}"
+        raise ArgumentError, msg
     end
   end
 
   # Gets the index of field.
   defp index(tag, fields, field) do
-    find_index(fields, field, 1) ||
-      raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(field)}"
+    if index = find_index(fields, field, 0) do
+      index - 1 # Convert to Elixir index
+    else
+      raise ArgumentError, "record #{inspect tag} 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
-    # Using {} here is safe, since it's not valid AST
-    default = if Macro.Env.in_match?(caller), do: {:_, [], nil}, else: {}
-    {default, keyword} = Keyword.pop(keyword, :_, default)
+    in_match = Macro.Env.in_match?(caller)
+    keyword = apply_underscore(fields, keyword)
 
-    {elements, remaining} =
-      Enum.map_reduce(fields, keyword, fn {key, field_default}, remaining ->
-        case Keyword.pop(remaining, key, default) do
-          {{}, remaining} -> {Macro.escape(field_default), remaining}
-          {default, remaining} -> {default, remaining}
-        end
+    {match, remaining} =
+      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)
+          end
+
+        {new_fields, Keyword.delete(each_keyword, field)}
       end)
 
     case remaining do
       [] ->
-        quote(do: {unquote(tag), unquote_splicing(elements)})
-
-      [{key, _} | _] ->
-        raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(key)}"
+        {:{}, [], [tag | match]}
+      _  ->
+        keys = for {key, _} <- remaining, do: key
+        raise ArgumentError, "record #{inspect tag} does not have the key: #{inspect hd(keys)}"
     end
   end
 
@@ -412,65 +387,33 @@ defmodule Record do
       raise ArgumentError, "cannot invoke update style macro inside match"
     end
 
-    if Keyword.has_key?(keyword, :_) do
-      message = "updating a record with a default (:_) is equivalent to creating a new record"
-      IO.warn(message, Macro.Env.stacktrace(caller))
-      create(tag, fields, keyword, caller)
-    else
-      case build_updates(keyword, fields, [], [], []) do
-        {updates, [], []} ->
-          build_update(updates, var)
+    keyword = apply_underscore(fields, keyword)
 
-        {updates, vars, exprs} ->
-          quote do
-            {unquote_splicing(:lists.reverse(vars))} = {unquote_splicing(:lists.reverse(exprs))}
-            unquote(build_update(updates, var))
-          end
-
-        {:error, key} ->
-          raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(key)}"
-      end
-    end
-  end
-
-  defp build_update(updates, initial) do
-    updates
-    |> Enum.sort(fn {left, _}, {right, _} -> right <= left end)
-    |> Enum.reduce(initial, fn {key, value}, acc ->
-      quote(do: :erlang.setelement(unquote(key), unquote(acc), unquote(value)))
-    end)
-  end
-
-  defp build_updates([{key, value} | rest], fields, updates, vars, exprs) do
-    if index = find_index(fields, key, 2) do
-      if simple_argument?(value) do
-        build_updates(rest, fields, [{index, value} | updates], vars, exprs)
+    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
-        var = Macro.var(key, __MODULE__)
-        build_updates(rest, fields, [{index, var} | updates], [var | vars], [value | exprs])
+        raise ArgumentError, "record #{inspect tag} does not have the key: #{inspect key}"
       end
-    else
-      {:error, key}
     end
   end
 
-  defp build_updates([], _fields, updates, vars, exprs), do: {updates, vars, exprs}
-
-  defp simple_argument?({name, _, ctx}) when is_atom(name) and is_atom(ctx), do: true
-  defp simple_argument?(other), do: Macro.quoted_literal?(other)
-
   # Gets a record key from the given var.
   defp get(tag, fields, var, key) do
-    index =
-      find_index(fields, key, 2) ||
-        raise ArgumentError, "record #{inspect(tag)} does not have the key: #{inspect(key)}"
-
-    quote do
-      :erlang.element(unquote(index), unquote(var))
+    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}"
     end
   end
 
-  defp find_index([{k, _} | _], k, i), do: i
+  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
 
@@ -479,27 +422,36 @@ defmodule Record do
   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)
+          msg = "expected argument to be a #{inspect tag} record with #{expected_fields} fields, got: #{inspect record}"
+          raise ArgumentError, msg
       end
     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 tag} 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) # expected fields
 
-  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
 end

lib/elixir/lib/record/extractor.ex

@@ -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)
-
     case :code.where_is_file(file) do
       :non_existing -> file
       realfile -> realfile
@@ -35,33 +37,28 @@ 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))
-
     case :code.lib_dir(List.to_atom(app)) do
       {:error, _} ->
         raise ArgumentError, "lib file #{file} could not be found"
-
       libpath ->
         :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

lib/elixir/lib/regex.ex

@@ -7,9 +7,9 @@ defmodule Regex do
   in the [`:re` module documentation](http://www.erlang.org/doc/man/re.html).
 
   Regular expressions in Elixir can be created using the sigils
-  `~r` (see `Kernel.sigil_r/2`) or `~R` (see `Kernel.sigil_R/2`):
+  [`~r`](Kernel.html#sigil_r/2) or [`~R`](Kernel.html#sigil_R/2):
 
-      # A simple regular expression that matches foo anywhere in the string
+      # A simple regular expressions that matches foo anywhere in the string
       ~r/foo/
 
       # A regular expression with case insensitive and Unicode options
@@ -26,7 +26,7 @@ defmodule Regex do
 
       ~r/(?<foo>.)(?<bar>.)/ == ~r/(?<foo>.)(?<bar>.)/
 
-  may return `true` or `false` depending on your machine, endianness,
+  may return `true` or `false` depending on your machine, endianess,
   available optimizations and others. You can, however, retrieve the source
   of a compiled regular expression by accessing the `source` field, and then
   compare those directly:
@@ -40,11 +40,11 @@ defmodule Regex do
   different OTP releases, as OTP releases may update the underlying regular
   expression engine at any time.
 
-  For such reasons, we always recommend precompiling Elixir projects using
-  the Erlang/OTP version meant to run in production. In case cross-compilation is
-  really necessary, you can manually invoke `Regex.recompile/1` or
-  `Regex.recompile!/1` to perform a runtime version check and recompile the
-  regex if necessary.
+  For such reasons, we always recomend precompiling Elixir projects using
+  the OTP version meant to run in production. In case cross-compilation is
+  really necessary, you can manually invoke `Regex.recompile/1` or `Regex.
+  recompile!/1` to perform a runtime version check and recompile the regex
+  if necessary.
 
   ## Modifiers
 
@@ -58,7 +58,7 @@ defmodule Regex do
 
     * `dotall` (s) - causes dot to match newlines and also set newline to
       anycrlf; the new line setting can be overridden by setting `(*CR)` or
-      `(*LF)` or `(*CRLF)` or `(*ANY)` according to `:re` documentation
+      `(*LF)` or `(*CRLF)` or `(*ANY)` according to re documentation
 
     * `multiline` (m) - causes `^` and `$` to mark the beginning and end of
       each line; use `\A` and `\z` to match the end or beginning of the string
@@ -79,7 +79,7 @@ defmodule Regex do
     * `no_auto_capture` - not available, use `?:` instead
     * `newline` - not available, use `(*CR)` or `(*LF)` or `(*CRLF)` or
       `(*ANYCRLF)` or `(*ANY)` at the beginning of the regexp according to the
-      `:re` documentation
+      re documentation
 
   ## Captures
 
@@ -93,7 +93,7 @@ defmodule Regex do
       complete matching part of the string; all explicitly captured subpatterns
       are discarded
 
-    * `:all_but_first` - all but the first matching subpattern, i.e. all
+    * `:all_but_first`- all but the first matching subpattern, i.e. all
       explicitly captured subpatterns, but not the complete matching part of
       the string
 
@@ -117,9 +117,8 @@ defmodule Regex do
   Compiles the regular expression.
 
   The given options can either be a binary with the characters
-  representing the same regex options given to the
-  `~r` (see `Kernel.sigil_r/2`) sigil, or a list of options, as
-  expected by the Erlang's `:re` module.
+  representing the same regex options given to the `~r` sigil,
+  or a list of options, as expected by the Erlang's `:re` module.
 
   It returns `{:ok, regex}` in case of success,
   `{:error, reason}` otherwise.
@@ -127,14 +126,14 @@ defmodule Regex do
   ## Examples
 
       iex> Regex.compile("foo")
-      {:ok, ~r/foo/}
+      {:ok, ~r"foo"}
 
       iex> Regex.compile("*foo")
       {:error, {'nothing to repeat', 0}}
 
   """
   @spec compile(binary, binary | [term]) :: {:ok, t} | {:error, any}
-  def compile(source, options \\ "") when is_binary(source) do
+  def compile(source, options \\ "") do
     compile(source, options, version())
   end
 
@@ -152,11 +151,10 @@ defmodule Regex do
     compile(source, options, "", version)
   end
 
-  defp compile(source, opts, doc_opts, version) do
+  defp compile(source, opts, doc_opts, version) when is_binary(source) do
     case :re.compile(source, opts) do
       {:ok, re_pattern} ->
         {:ok, %Regex{re_pattern: re_pattern, re_version: version, source: source, opts: doc_opts}}
-
       error ->
         error
     end
@@ -166,7 +164,7 @@ defmodule Regex do
   Compiles the regular expression and raises `Regex.CompileError` in case of errors.
   """
   @spec compile!(binary, binary | [term]) :: t
-  def compile!(source, options \\ "") when is_binary(source) do
+  def compile!(source, options \\ "") do
     case compile(source, options) do
       {:ok, regex} -> regex
       {:error, {reason, at}} -> raise Regex.CompileError, "#{reason} at position #{at}"
@@ -179,15 +177,14 @@ defmodule Regex do
   This checks the version stored in the regular expression
   and recompiles the regex in case of version mismatch.
   """
-  @doc since: "1.4.0"
   @spec recompile(t) :: t
   def recompile(%Regex{} = regex) do
     version = version()
 
-    case regex do
-      %{re_version: ^version} ->
+    # We use Map.get/3 by choice to support old regexes versions.
+    case Map.get(regex, :re_version, :error) do
+      ^version ->
         {:ok, regex}
-
       _ ->
         %{source: source, opts: opts} = regex
         compile(source, opts, version)
@@ -197,7 +194,6 @@ defmodule Regex do
   @doc """
   Recompiles the existing regular expression and raises `Regex.CompileError` in case of errors.
   """
-  @doc since: "1.4.0"
   @spec recompile!(t) :: t
   def recompile!(regex) do
     case recompile(regex) do
@@ -209,10 +205,13 @@ defmodule Regex do
   @doc """
   Returns the version of the underlying Regex engine.
   """
-  @doc since: "1.4.0"
-  @spec version :: term()
+  # TODO: No longer check for function_exported? on OTP 20+.
   def version do
-    {:re.version(), :erlang.system_info(:endian)}
+    if function_exported?(:re, :version, 0) do
+      :re.version()
+    else
+      "8.33 2013-05-29"
+    end
   end
 
   @doc """
@@ -227,7 +226,7 @@ defmodule Regex do
       false
 
   """
-  @spec match?(t, String.t()) :: boolean
+  @spec match?(t, String.t) :: boolean
   def match?(%Regex{re_pattern: compiled}, string) when is_binary(string) do
     :re.run(string, compiled, [{:capture, :none}]) == :match
   end
@@ -256,8 +255,7 @@ defmodule Regex do
 
   ## Options
 
-    * `:return` - set to `:index` to return byte index and match length.
-      Defaults to `:binary`.
+    * `:return`  - sets to `:index` to return indexes. Defaults to `:binary`.
     * `:capture` - what to capture in the result. Check the moduledoc for `Regex`
       to see the possible capture values.
 
@@ -277,23 +275,20 @@ defmodule Regex do
   def run(regex, string, options \\ [])
 
   def run(%Regex{re_pattern: compiled}, string, options) when is_binary(string) do
-    return = Keyword.get(options, :return, :binary)
+    return   = Keyword.get(options, :return, :binary)
     captures = Keyword.get(options, :capture, :all)
 
     case :re.run(string, compiled, [{:capture, captures, return}]) do
       :nomatch -> nil
-      :match -> []
+      :match   -> []
       {:match, results} -> results
     end
   end
 
   @doc """
-  Returns the given captures as a map or `nil` if no captures are found.
-
-  ## Options
-
-    * `:return` - set to `:index` to return byte index and match length.
-      Defaults to `:binary`.
+  Returns the given captures as a map or `nil` if no captures are
+  found. The option `:return` can be set to `:index` to get indexes
+  back.
 
   ## Examples
 
@@ -307,7 +302,7 @@ defmodule Regex do
       nil
 
   """
-  @spec named_captures(t, String.t(), [term]) :: map | nil
+  @spec named_captures(t, String.t, [term]) :: map | nil
   def named_captures(regex, string, options \\ []) when is_binary(string) do
     names = names(regex)
     options = Keyword.put(options, :capture, names)
@@ -332,7 +327,7 @@ defmodule Regex do
       "foo"
 
   """
-  @spec source(t) :: String.t()
+  @spec source(t) :: String.t
   def source(%Regex{source: source}) do
     source
   end
@@ -346,7 +341,7 @@ defmodule Regex do
       "m"
 
   """
-  @spec opts(t) :: String.t()
+  @spec opts(t) :: String.t
   def opts(%Regex{opts: opts}) do
     opts
   end
@@ -360,7 +355,7 @@ defmodule Regex do
       ["foo"]
 
   """
-  @spec names(t) :: [String.t()]
+  @spec names(t) :: [String.t]
   def names(%Regex{re_pattern: re_pattern}) do
     {:namelist, names} = :re.inspect(re_pattern, :namelist)
     names
@@ -375,8 +370,7 @@ defmodule Regex do
 
   ## Options
 
-    * `:return` - set to `:index` to return byte index and match length.
-      Defaults to `:binary`.
+    * `:return`  - sets to `:index` to return indexes. Defaults to `:binary`.
     * `:capture` - what to capture in the result. Check the moduledoc for `Regex`
       to see the possible capture values.
 
@@ -394,17 +388,14 @@ defmodule Regex do
       iex> Regex.scan(~r/\p{Sc}/u, "$, £, and €")
       [["$"], ["£"], ["€"]]
 
-      iex> Regex.scan(~r/=+/, "=ü†ƒ8===", return: :index)
-      [[{0, 1}], [{9, 3}]]
-
   """
-  @spec scan(t, String.t(), [term]) :: [[String.t()]]
+  @spec scan(t, String.t, [term]) :: [[String.t]]
   def scan(regex, string, options \\ [])
 
   def scan(%Regex{re_pattern: compiled}, string, options) when is_binary(string) do
-    return = Keyword.get(options, :return, :binary)
+    return   = Keyword.get(options, :return, :binary)
     captures = Keyword.get(options, :capture, :all)
-    options = [{:capture, captures, return}, :global]
+    options  = [{:capture, captures, return}, :global]
 
     case :re.run(string, compiled, options) do
       :match -> []
@@ -425,7 +416,6 @@ defmodule Regex do
       given pattern.
 
     * `:trim` - when `true`, removes empty strings (`""`) from the result.
-      Defaults to `false`.
 
     * `:on` - specifies which captures to split the string on, and in what
       order. Defaults to `:first` which means captures inside the regex do not
@@ -439,14 +429,14 @@ defmodule Regex do
       iex> Regex.split(~r{-}, "a-b-c")
       ["a", "b", "c"]
 
-      iex> Regex.split(~r{-}, "a-b-c", parts: 2)
+      iex> Regex.split(~r{-}, "a-b-c", [parts: 2])
       ["a", "b-c"]
 
       iex> Regex.split(~r{-}, "abc")
       ["abc"]
 
       iex> Regex.split(~r{}, "abc")
-      ["", "a", "b", "c", ""]
+      ["a", "b", "c", ""]
 
       iex> Regex.split(~r{a(?<second>b)c}, "abc")
       ["", ""]
@@ -461,7 +451,7 @@ defmodule Regex do
       ["a", "b", "c"]
 
   """
-  @spec split(t, String.t(), [term]) :: [String.t()]
+  @spec split(t, String.t, [term]) :: [String.t]
   def split(regex, string, options \\ [])
 
   def split(%Regex{}, "", opts) do
@@ -472,32 +462,26 @@ defmodule Regex do
     end
   end
 
-  def split(%Regex{re_pattern: compiled}, string, opts)
-      when is_binary(string) and is_list(opts) do
+  def split(%Regex{re_pattern: compiled}, string, opts) when is_binary(string) and is_list(opts) do
     on = Keyword.get(opts, :on, :first)
-
     case :re.run(string, compiled, [:global, capture: on]) do
       {:match, matches} ->
-        index = parts_to_index(Keyword.get(opts, :parts, :infinity))
-        trim = Keyword.get(opts, :trim, false)
-        include_captures = Keyword.get(opts, :include_captures, false)
-        do_split(matches, string, 0, index, trim, include_captures)
-
+        do_split(matches, string, 0,
+                 parts_to_index(Keyword.get(opts, :parts, :infinity)),
+                 Keyword.get(opts, :trim, false),
+                 Keyword.get(opts, :include_captures, false))
       :match ->
         [string]
-
       :nomatch ->
         [string]
     end
   end
 
-  defp parts_to_index(:infinity), do: 0
+  defp parts_to_index(:infinity),                      do: 0
   defp parts_to_index(n) when is_integer(n) and n > 0, do: n
 
-  defp do_split(_, string, offset, _counter, true, _with_captures)
-       when byte_size(string) <= offset do
-    []
-  end
+  defp do_split(_, string, offset, _counter, true, _with_captures) when byte_size(string) <= offset,
+    do: []
 
   defp do_split(_, string, offset, 1, _trim, _with_captures),
     do: [binary_part(string, offset, byte_size(string) - offset)]
@@ -505,10 +489,8 @@ defmodule Regex do
   defp do_split([], string, offset, _counter, _trim, _with_captures),
     do: [binary_part(string, offset, byte_size(string) - offset)]
 
-  defp do_split([[{pos, _} | h] | t], string, offset, counter, trim, with_captures)
-       when pos - offset < 0 do
-    do_split([h | t], string, offset, counter, trim, with_captures)
-  end
+  defp do_split([[{pos, _} | h] | t], string, offset, counter, trim, with_captures) when pos - offset < 0,
+    do: do_split([h | t], string, offset, counter, trim, with_captures)
 
   defp do_split([[] | t], string, offset, counter, trim, with_captures),
     do: do_split(t, string, offset, counter, trim, with_captures)
@@ -517,13 +499,16 @@ defmodule Regex do
     new_offset = pos + length
     keep = pos - offset
 
-    <<_::binary-size(offset), part::binary-size(keep), match::binary-size(length), _::binary>> =
-      string
-
-    if keep == 0 and trim do
-      [match | do_split([h | t], string, new_offset, counter - 1, trim, true)]
+    if keep == 0 and length == 0 do
+      do_split([h | t], string, new_offset, counter, trim, true)
     else
-      [part, match | do_split([h | t], string, new_offset, counter - 1, trim, true)]
+      <<_::binary-size(offset), part::binary-size(keep), match::binary-size(length), _::binary>> = string
+
+      if keep == 0 and (length == 0 or trim) do
+        [match | do_split([h | t], string, new_offset, counter - 1, trim, true)]
+      else
+        [part, match | do_split([h | t], string, new_offset, counter - 1, trim, true)]
+      end
     end
   end
 
@@ -531,7 +516,7 @@ defmodule Regex do
     new_offset = pos + length
     keep = pos - offset
 
-    if keep == 0 and trim do
+    if keep == 0 and (length == 0 or trim) do
       do_split([h | t], string, new_offset, counter, trim, false)
     else
       <<_::binary-size(offset), part::binary-size(keep), _::binary>> = string
@@ -584,7 +569,7 @@ defmodule Regex do
       "Abcadc"
 
   """
-  @spec replace(t, String.t(), String.t() | (... -> String.t()), [term]) :: String.t()
+  @spec replace(t, String.t, String.t | (... -> String.t), [term]) :: String.t
   def replace(regex, string, replacement, options \\ [])
 
   def replace(regex, string, replacement, options)
@@ -593,8 +578,8 @@ defmodule Regex do
   end
 
   def replace(regex, string, replacement, options)
-      when is_binary(string) and is_function(replacement) and is_list(options) do
-    {:arity, arity} = Function.info(replacement, :arity)
+      when is_binary(string) and is_function(replacement) and is_list(options)  do
+    {:arity, arity} = :erlang.fun_info(replacement, :arity)
     do_replace(regex, string, {replacement, arity}, options)
   end
 
@@ -605,16 +590,15 @@ defmodule Regex do
     case :re.run(string, compiled, opts) do
       :nomatch ->
         string
-
       {:match, [mlist | t]} when is_list(mlist) ->
-        apply_list(string, replacement, [mlist | t]) |> IO.iodata_to_binary()
-
+        apply_list(string, replacement, [mlist | t]) |> IO.iodata_to_binary
       {:match, slist} ->
-        apply_list(string, replacement, [slist]) |> IO.iodata_to_binary()
+        apply_list(string, replacement, [slist]) |> IO.iodata_to_binary
     end
   end
 
-  defp precompile_replacement(""), do: []
+  defp precompile_replacement(""),
+    do: []
 
   defp precompile_replacement(<<?\\, ?g, ?{, rest::binary>>) when byte_size(rest) > 0 do
     {ns, <<?}, rest::binary>>} = pick_int(rest)
@@ -634,7 +618,6 @@ defmodule Regex do
     case precompile_replacement(rest) do
       [head | t] when is_binary(head) ->
         [<<x, head::binary>> | t]
-
       other ->
         [<<x>> | other]
     end
@@ -661,8 +644,7 @@ defmodule Regex do
     string
   end
 
-  defp apply_list(whole, string, pos, replacement, [[{mpos, _} | _] | _] = list)
-       when mpos > pos do
+  defp apply_list(whole, string, pos, replacement, [[{mpos, _} | _] | _] = list) when mpos > pos do
     length = mpos - pos
     <<untouched::binary-size(length), rest::binary>> = string
     [untouched | apply_list(whole, rest, mpos, replacement, list)]
@@ -689,10 +671,8 @@ defmodule Regex do
       cond do
         is_binary(part) ->
           part
-
         part >= tuple_size(indexes) ->
           ""
-
         true ->
           get_index(string, elem(indexes, part))
       end
@@ -732,11 +712,11 @@ defmodule Regex do
       "\\\\what\\ if"
 
   """
-  @spec escape(String.t()) :: String.t()
+  @spec escape(String.t) :: String.t
   def escape(string) when is_binary(string) do
     string
     |> escape(_length = 0, string)
-    |> IO.iodata_to_binary()
+    |> IO.iodata_to_binary
   end
 
   @escapable '.^$*+?()[]{}|#-\\\t\n\v\f\r\s'
@@ -771,7 +751,7 @@ defmodule Regex do
   def unescape_map(?t), do: ?\t
   def unescape_map(?v), do: ?\v
   def unescape_map(?a), do: ?\a
-  def unescape_map(_), do: false
+  def unescape_map(_),  do: false
 
   # Private Helpers
 
@@ -780,15 +760,12 @@ defmodule Regex do
   defp translate_options(<<?x, t::binary>>, acc), do: translate_options(t, [:extended | acc])
   defp translate_options(<<?f, t::binary>>, acc), do: translate_options(t, [:firstline | acc])
   defp translate_options(<<?U, t::binary>>, acc), do: translate_options(t, [:ungreedy | acc])
-
-  defp translate_options(<<?s, t::binary>>, acc),
-    do: translate_options(t, [:dotall, {:newline, :anycrlf} | acc])
-
+  defp translate_options(<<?s, t::binary>>, acc), do: translate_options(t, [:dotall, {:newline, :anycrlf} | acc])
   defp translate_options(<<?m, t::binary>>, acc), do: translate_options(t, [:multiline | acc])
 
   # TODO: Remove on 2.0
   defp translate_options(<<?r, t::binary>>, acc) do
-    IO.warn("the /r modifier in regular expressions is deprecated, please use /U instead")
+    IO.warn "the /r modifier in regular expressions is deprecated, please use /U instead"
     translate_options(t, [:ungreedy | acc])
   end
 

lib/elixir/lib/registry.ex

@@ -11,7 +11,7 @@ defmodule Registry do
   Each entry in the registry is associated to the process that has
   registered the key. If the process crashes, the keys associated to that
   process are automatically removed. All key comparisons in the registry
-  are done using the match operation (`===/2`).
+  are done using the match operation (`===`).
 
   The registry can be used for different purposes, such as name lookups (using
   the `:via` option), storing properties, custom dispatching rules, or a pubsub
@@ -32,26 +32,10 @@ defmodule Registry do
       {:ok, _} = Agent.start_link(fn -> 0 end, name: name)
       Agent.get(name, & &1)
       #=> 0
-      Agent.update(name, &(&1 + 1))
+      Agent.update(name, & &1 + 1)
       Agent.get(name, & &1)
       #=> 1
 
-  In the previous example, we were not interested in associating a value to the
-  process:
-
-      Registry.lookup(Registry.ViaTest, "agent")
-      #=> [{self(), nil}]
-
-  However, in some cases it may be desired to associate a value to the process
-  using the alternate `{:via, Registry, {registry, key, value}}` tuple:
-
-      {:ok, _} = Registry.start_link(keys: :unique, name: Registry.ViaTest)
-      name = {:via, Registry, {Registry.ViaTest, "agent", :hello}}
-      {:ok, _} = Agent.start_link(fn -> 0 end, name: name)
-      Registry.lookup(Registry.ViaTest, "agent")
-      #=> [{self(), :hello}]
-
-  To this point, we have been starting `Registry` using `start_link/1`.
   Typically the registry is started as part of a supervision tree though:
 
       {Registry, keys: :unique, name: Registry.ViaTest}
@@ -99,15 +83,14 @@ defmodule Registry do
   errors:
 
       require Logger
-
       Registry.dispatch(Registry.DispatcherTest, "hello", fn entries ->
         for {pid, {module, function}} <- entries do
           try do
             apply(module, function, [pid])
           catch
             kind, reason ->
-              formatted = Exception.format(kind, reason, __STACKTRACE__)
-              Logger.error("Registry.dispatch/3 failed with #{formatted}")
+              formatted = Exception.format(kind, reason, System.stacktrace)
+              Logger.error "Registry.dispatch/3 failed with #{formatted}"
           end
         end
       end)
@@ -128,15 +111,9 @@ defmodule Registry do
   schedulers online, which will make the registry more performant on highly
   concurrent environments:
 
-      {:ok, _} =
-        Registry.start_link(
-          keys: :duplicate,
-          name: Registry.PubSubTest,
-          partitions: System.schedulers_online()
-        )
-
+      {:ok, _} = Registry.start_link(keys: :duplicate, name: Registry.PubSubTest,
+                                     partitions: System.schedulers_online)
       {:ok, _} = Registry.register(Registry.PubSubTest, "hello", [])
-
       Registry.dispatch(Registry.PubSubTest, "hello", fn entries ->
         for {pid, _} <- entries, do: send(pid, {:broadcast, "world"})
       end)
@@ -194,45 +171,27 @@ defmodule Registry do
   @typedoc "The type of registry metadata values"
   @type meta_value :: term
 
-  @typedoc "A pattern to match on objects in a registry"
-  @type match_pattern :: atom | term
-
-  @typedoc "A guard to be evaluated when matching on objects in a registry"
-  @type guard :: {atom | term}
-
-  @typedoc "A list of guards to be evaluated when matching on objects in a registry"
-  @type guards :: [guard] | []
-
   ## Via callbacks
 
   @doc false
-  def whereis_name({registry, key}), do: whereis_name(registry, key)
-  def whereis_name({registry, key, _value}), do: whereis_name(registry, key)
-
-  defp whereis_name(registry, key) do
+  def whereis_name({registry, key}) do
     case key_info!(registry) do
       {:unique, partitions, key_ets} ->
         key_ets = key_ets || key_ets!(registry, key, partitions)
-
         case safe_lookup_second(key_ets, key) do
           {pid, _} ->
             if Process.alive?(pid), do: pid, else: :undefined
-
           _ ->
             :undefined
         end
-
       {kind, _, _} ->
         raise ArgumentError, ":via is not supported for #{kind} registries"
     end
   end
 
   @doc false
-  def register_name({registry, key}, pid), do: register_name(registry, key, nil, pid)
-  def register_name({registry, key, value}, pid), do: register_name(registry, key, value, pid)
-
-  defp register_name(registry, key, value, pid) when pid == self() do
-    case register(registry, key, value) do
+  def register_name({registry, key}, pid) when pid == self() do
+    case register(registry, key, nil) do
       {:ok, _} -> :yes
       {:error, _} -> :no
     end
@@ -264,23 +223,21 @@ defmodule Registry do
 
       Supervisor.start_link([
         {Registry, keys: :unique, name: MyApp.Registry}
-      ], strategy: :one_for_one)
+      ])
 
   For intensive workloads, the registry may also be partitioned (by specifying
   the `:partitions` option). If partitioning is required then a good default is to
   set the number of partitions to the number of schedulers available:
 
-      Registry.start_link(
-        keys: :unique,
-        name: MyApp.Registry,
-        partitions: System.schedulers_online()
-      )
+      Registry.start_link(keys: :unique, name: MyApp.Registry,
+                          partitions: System.schedulers_online())
 
   or:
 
       Supervisor.start_link([
-        {Registry, keys: :unique, name: MyApp.Registry, partitions: System.schedulers_online()}
-      ], strategy: :one_for_one)
+        {Registry, keys: :unique, name: MyApp.Registry,
+                   partitions: System.schedulers_online()}
+      ])
 
   ## Options
 
@@ -299,70 +256,52 @@ defmodule Registry do
     * `:meta` - a keyword list of metadata to be attached to the registry.
 
   """
-  @doc since: "1.5.0"
-  @spec start_link(
-          keys: keys,
-          name: registry,
-          partitions: pos_integer,
-          listeners: [atom],
-          meta: meta
-        ) :: {:ok, pid} | {:error, term}
-        when meta: [{meta_key, meta_value}]
+  @spec start_link(keys: keys, name: registry, partitions: pos_integer, listeners: [atom],
+                   meta: [{meta_key, meta_value}]) :: {:ok, pid} | {:error, term}
   def start_link(options) do
     keys = Keyword.get(options, :keys)
-
     unless keys in @keys do
-      raise ArgumentError,
-            "expected :keys to be given and be one of :unique or :duplicate, got: #{inspect(keys)}"
+      raise ArgumentError, "expected :keys to be given and be one of :unique or :duplicate, got: #{inspect keys}"
     end
 
     name = Keyword.get(options, :name)
-
     unless is_atom(name) do
-      raise ArgumentError, "expected :name to be given and to be an atom, got: #{inspect(name)}"
+      raise ArgumentError, "expected :name to be given and to be an atom, got: #{inspect name}"
     end
 
     meta = Keyword.get(options, :meta, [])
-
     unless Keyword.keyword?(meta) do
-      raise ArgumentError, "expected :meta to be a keyword list, got: #{inspect(meta)}"
+      raise ArgumentError, "expected :meta to be a keyword list, got: #{inspect meta}"
     end
 
     partitions = Keyword.get(options, :partitions, 1)
-
     unless is_integer(partitions) and partitions >= 1 do
-      raise ArgumentError,
-            "expected :partitions to be a positive integer, got: #{inspect(partitions)}"
+      raise ArgumentError, "expected :partitions to be a positive integer, got: #{inspect partitions}"
     end
 
     listeners = Keyword.get(options, :listeners, [])
-
     unless is_list(listeners) and Enum.all?(listeners, &is_atom/1) do
-      raise ArgumentError,
-            "expected :listeners to be a list of named processes, got: #{inspect(listeners)}"
+      raise ArgumentError, "expected :listeners to be a list of named processes, got: #{inspect listeners}"
     end
 
     # The @info format must be kept in sync with Registry.Partition optimization.
-    entries = [
-      {@all_info, {keys, partitions, nil, nil, listeners}},
-      {@key_info, {keys, partitions, nil}} | meta
-    ]
-
+    entries = [{@all_info, {keys, partitions, nil, nil, listeners}},
+               {@key_info, {keys, partitions, nil}} | meta]
     Registry.Supervisor.start_link(keys, name, partitions, listeners, entries)
   end
 
-  @doc false
-  @deprecated "Use Registry.start_link/1 instead"
+  @doc """
+  Starts the registry as a supervisor process.
+
+  Similar to `start_link/1` except the required options,
+  `keys` and `name` are given as arguments.
+  """
+  @spec start_link(keys, registry, keyword) :: {:ok, pid} | {:error, term}
   def start_link(keys, name, options \\ []) when keys in @keys and is_atom(name) do
     start_link([keys: keys, name: name] ++ options)
   end
 
-  @doc """
-  Returns a specification to start a registry under a supervisor.
-
-  See `Supervisor`.
-  """
-  @doc since: "1.5.0"
+  @doc false
   def child_spec(opts) do
     %{
       id: Keyword.get(opts, :name, Registry),
@@ -381,24 +320,21 @@ defmodule Registry do
 
   ## Examples
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UpdateTest)
+      iex> Registry.start_link(:unique, Registry.UpdateTest)
       iex> {:ok, _} = Registry.register(Registry.UpdateTest, "hello", 1)
       iex> Registry.lookup(Registry.UpdateTest, "hello")
       [{self(), 1}]
-      iex> Registry.update_value(Registry.UpdateTest, "hello", &(&1 + 1))
+      iex> Registry.update_value(Registry.UpdateTest, "hello", & &1 + 1)
       {2, 1}
       iex> Registry.lookup(Registry.UpdateTest, "hello")
       [{self(), 2}]
 
   """
-  @doc since: "1.4.0"
-  @spec update_value(registry, key, (value -> value)) ::
-          {new_value :: term, old_value :: term} | :error
+  @spec update_value(registry, key, (value -> value)) :: {new_value :: term, old_value :: term} | :error
   def update_value(registry, key, callback) when is_atom(registry) and is_function(callback, 1) do
     case key_info!(registry) do
       {:unique, partitions, key_ets} ->
         key_ets = key_ets || key_ets!(registry, key, partitions)
-
         try do
           :ets.lookup_element(key_ets, key, 2)
         catch
@@ -408,11 +344,9 @@ defmodule Registry do
             new_value = callback.(old_value)
             :ets.insert(key_ets, {key, {pid, new_value}})
             {new_value, old_value}
-
           {_, _} ->
             :error
         end
-
       {kind, _, _} ->
         raise ArgumentError, "Registry.update_value/3 is not supported for #{kind} registries"
     end
@@ -435,9 +369,7 @@ defmodule Registry do
   See the module documentation for examples of using the `dispatch/3`
   function for building custom dispatching or a pubsub system.
   """
-  @doc since: "1.4.0"
-  @spec dispatch(registry, key, dispatcher, keyword) :: :ok
-        when dispatcher: (entries :: [{pid, value}] -> term) | {module(), atom(), [any()]}
+  @spec dispatch(registry, key, (entries :: [{pid, value}] -> term), keyword) :: :ok
   def dispatch(registry, key, mfa_or_fun, opts \\ [])
       when is_atom(registry) and is_function(mfa_or_fun, 1)
       when is_atom(registry) and tuple_size(mfa_or_fun) == 3 do
@@ -447,12 +379,10 @@ defmodule Registry do
         |> safe_lookup_second(key)
         |> List.wrap()
         |> apply_non_empty_to_mfa_or_fun(mfa_or_fun)
-
       {:duplicate, 1, key_ets} ->
         key_ets
         |> safe_lookup_second(key)
         |> apply_non_empty_to_mfa_or_fun(mfa_or_fun)
-
       {:duplicate, partitions, _} ->
         if Keyword.get(opts, :parallel, false) do
           registry
@@ -462,55 +392,44 @@ defmodule Registry do
           dispatch_serial(registry, key, mfa_or_fun, partitions)
         end
     end
-
     :ok
   end
 
   defp dispatch_serial(_registry, _key, _mfa_or_fun, 0) do
     :ok
   end
-
   defp dispatch_serial(registry, key, mfa_or_fun, partition) do
     partition = partition - 1
-
     registry
     |> key_ets!(partition)
     |> safe_lookup_second(key)
     |> apply_non_empty_to_mfa_or_fun(mfa_or_fun)
-
     dispatch_serial(registry, key, mfa_or_fun, partition)
   end
 
   defp dispatch_parallel(_registry, _key, _mfa_or_fun, 0) do
     []
   end
-
   defp dispatch_parallel(registry, key, mfa_or_fun, partition) do
     partition = partition - 1
     parent = self()
-
-    task =
-      Task.async(fn ->
-        registry
-        |> key_ets!(partition)
-        |> safe_lookup_second(key)
-        |> apply_non_empty_to_mfa_or_fun(mfa_or_fun)
-
-        Process.unlink(parent)
-        :ok
-      end)
-
+    task = Task.async(fn ->
+      registry
+      |> key_ets!(partition)
+      |> safe_lookup_second(key)
+      |> apply_non_empty_to_mfa_or_fun(mfa_or_fun)
+      Process.unlink(parent)
+      :ok
+    end)
     [task | dispatch_parallel(registry, key, mfa_or_fun, partition)]
   end
 
   defp apply_non_empty_to_mfa_or_fun([], _mfa_or_fun) do
     :ok
   end
-
   defp apply_non_empty_to_mfa_or_fun(entries, {module, function, args}) do
     apply(module, function, [entries | args])
   end
-
   defp apply_non_empty_to_mfa_or_fun(entries, fun) do
     fun.(entries)
   end
@@ -528,18 +447,18 @@ defmodule Registry do
   In the example below we register the current process and look it up
   both from itself and other processes:
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueLookupTest)
+      iex> Registry.start_link(:unique, Registry.UniqueLookupTest)
       iex> Registry.lookup(Registry.UniqueLookupTest, "hello")
       []
       iex> {:ok, _} = Registry.register(Registry.UniqueLookupTest, "hello", :world)
       iex> Registry.lookup(Registry.UniqueLookupTest, "hello")
       [{self(), :world}]
-      iex> Task.async(fn -> Registry.lookup(Registry.UniqueLookupTest, "hello") end) |> Task.await()
+      iex> Task.async(fn -> Registry.lookup(Registry.UniqueLookupTest, "hello") end) |> Task.await
       [{self(), :world}]
 
   The same applies to duplicate registries:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateLookupTest)
+      iex> Registry.start_link(:duplicate, Registry.DuplicateLookupTest)
       iex> Registry.lookup(Registry.DuplicateLookupTest, "hello")
       []
       iex> {:ok, _} = Registry.register(Registry.DuplicateLookupTest, "hello", :world)
@@ -550,17 +469,14 @@ defmodule Registry do
       [{self(), :another}, {self(), :world}]
 
   """
-  @doc since: "1.4.0"
   @spec lookup(registry, key) :: [{pid, value}]
   def lookup(registry, key) when is_atom(registry) do
     case key_info!(registry) do
       {:unique, partitions, key_ets} ->
         key_ets = key_ets || key_ets!(registry, key, partitions)
-
         case safe_lookup_second(key_ets, key) do
           {_, _} = pair ->
             [pair]
-
           _ ->
             []
         end
@@ -580,14 +496,14 @@ defmodule Registry do
 
   Pattern must be an atom or a tuple that will match the structure of the
   value stored in the registry. The atom `:_` can be used to ignore a given
-  value or tuple element, while the atom `:"$1"` can be used to temporarily assign part
+  value or tuple element, while :"$1" can be used to temporarily assign part
   of pattern to a variable for a subsequent comparison.
 
-  Optionally, it is possible to pass a list of guard conditions for more precise matching.
-  Each guard is a tuple, which describes checks that should be passed by assigned part of pattern.
-  For example the `$1 > 1` guard condition would be expressed as the `{:>, :"$1", 1}` tuple.
-  Please note that guard conditions will work only for assigned variables like `:"$1"`, `:"$2"`, etc.
-  Avoid usage of special match variables `:"$_"` and `:"$$"`, because it might not work as expected.
+  It is possible to pass list of guard conditions for more precise matching.
+  Each guard is a tuple, which describes check that should be passed by assigned part of pattern.
+  For example :"$1" > 1 guard condition would be expressed as {:>, :"$1", 1} tuple.
+  Please note that guard conditions will work only for assigned variables like :"$1", :"$2", etc.
+  Avoid usage of special match variables :"$_" and :"$$", because it might not work as expected.
 
   An empty list will be returned if there is no match.
 
@@ -599,7 +515,7 @@ defmodule Registry do
   In the example below we register the current process under the same
   key in a duplicate registry but with different values:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.MatchTest)
+      iex> Registry.start_link(:duplicate, Registry.MatchTest)
       iex> {:ok, _} = Registry.register(Registry.MatchTest, "hello", {1, :atom, 1})
       iex> {:ok, _} = Registry.register(Registry.MatchTest, "hello", {2, :atom, 2})
       iex> Registry.match(Registry.MatchTest, "hello", {1, :_, :_})
@@ -610,16 +526,13 @@ defmodule Registry do
       [{self(), {1, :atom, 1}}, {self(), {2, :atom, 2}}]
       iex> Registry.match(Registry.MatchTest, "hello", {:"$1", :_, :"$1"}) |> Enum.sort()
       [{self(), {1, :atom, 1}}, {self(), {2, :atom, 2}}]
-      iex> guards = [{:>, :"$1", 1}]
-      iex> Registry.match(Registry.MatchTest, "hello", {:_, :_, :"$1"}, guards)
+      iex> Registry.match(Registry.MatchTest, "hello", {:_, :_, :"$1"}, [{:>, :"$1", 1}])
       [{self(), {2, :atom, 2}}]
-      iex> guards = [{:is_atom, :"$1"}]
-      iex> Registry.match(Registry.MatchTest, "hello", {:_, :"$1", :_}, guards) |> Enum.sort()
+      iex> Registry.match(Registry.MatchTest, "hello", {:_, :"$1", :_}, [{:is_atom, :"$1"}]) |> Enum.sort()
       [{self(), {1, :atom, 1}}, {self(), {2, :atom, 2}}]
 
   """
-  @doc since: "1.4.0"
-  @spec match(registry, key, match_pattern, guards) :: [{pid, term}]
+  @spec match(registry, key, match_pattern :: atom() | tuple(), guards :: list()) :: [{pid, term}]
   def match(registry, key, pattern, guards \\ []) when is_atom(registry) and is_list(guards) do
     guards = [{:"=:=", {:element, 1, :"$_"}, {:const, key}} | guards]
     spec = [{{:_, {:_, pattern}}, guards, [{:element, 2, :"$_"}]}]
@@ -651,7 +564,7 @@ defmodule Registry do
 
   Registering under a unique registry does not allow multiple entries:
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueKeysTest)
+      iex> Registry.start_link(:unique, Registry.UniqueKeysTest)
       iex> Registry.keys(Registry.UniqueKeysTest, self())
       []
       iex> {:ok, _} = Registry.register(Registry.UniqueKeysTest, "hello", :world)
@@ -662,7 +575,7 @@ defmodule Registry do
 
   Such is possible for duplicate registries though:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateKeysTest)
+      iex> Registry.start_link(:duplicate, Registry.DuplicateKeysTest)
       iex> Registry.keys(Registry.DuplicateKeysTest, self())
       []
       iex> {:ok, _} = Registry.register(Registry.DuplicateKeysTest, "hello", :world)
@@ -671,19 +584,17 @@ defmodule Registry do
       ["hello", "hello"]
 
   """
-  @doc since: "1.4.0"
   @spec keys(registry, pid) :: [key]
   def keys(registry, pid) when is_atom(registry) and is_pid(pid) do
     {kind, partitions, _, pid_ets, _} = info!(registry)
     {_, pid_ets} = pid_ets || pid_ets!(registry, pid, partitions)
 
-    keys =
-      try do
-        spec = [{{pid, :"$1", :"$2"}, [], [{{:"$1", :"$2"}}]}]
-        :ets.select(pid_ets, spec)
-      catch
-        :error, :badarg -> []
-      end
+    keys = try do
+      spec = [{{pid, :'$1', :'$2'}, [], [{{:'$1', :'$2'}}]}]
+      :ets.select(pid_ets, spec)
+    catch
+      :error, :badarg -> []
+    end
 
     # Handle the possibility of fake keys
     keys = gather_keys(keys, [], false)
@@ -697,15 +608,12 @@ defmodule Registry do
   defp gather_keys([{key, {_, remaining}} | rest], acc, _fake) do
     gather_keys(rest, [key | acc], {key, remaining})
   end
-
   defp gather_keys([{key, _} | rest], acc, fake) do
     gather_keys(rest, [key | acc], fake)
   end
-
   defp gather_keys([], acc, {key, remaining}) do
-    List.duplicate(key, remaining) ++ Enum.reject(acc, &(&1 === key))
+    List.duplicate(key, remaining) ++ Enum.reject(acc, & &1 === key)
   end
-
   defp gather_keys([], acc, false) do
     acc
   end
@@ -722,7 +630,7 @@ defmodule Registry do
 
   For unique registries:
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueUnregisterTest)
+      iex> Registry.start_link(:unique, Registry.UniqueUnregisterTest)
       iex> Registry.register(Registry.UniqueUnregisterTest, "hello", :world)
       iex> Registry.keys(Registry.UniqueUnregisterTest, self())
       ["hello"]
@@ -733,7 +641,7 @@ defmodule Registry do
 
   For duplicate registries:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateUnregisterTest)
+      iex> Registry.start_link(:duplicate, Registry.DuplicateUnregisterTest)
       iex> Registry.register(Registry.DuplicateUnregisterTest, "hello", :world)
       iex> Registry.register(Registry.DuplicateUnregisterTest, "hello", :world)
       iex> Registry.keys(Registry.DuplicateUnregisterTest, self())
@@ -744,7 +652,6 @@ defmodule Registry do
       []
 
   """
-  @doc since: "1.4.0"
   @spec unregister(registry, key) :: :ok
   def unregister(registry, key) when is_atom(registry) do
     self = self()
@@ -776,7 +683,7 @@ defmodule Registry do
   For unique registries it can be used to conditionally unregister a key on
   the basis of whether or not it matches a particular value.
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueUnregisterMatchTest)
+      iex> Registry.start_link(:unique, Registry.UniqueUnregisterMatchTest)
       iex> Registry.register(Registry.UniqueUnregisterMatchTest, "hello", :world)
       iex> Registry.keys(Registry.UniqueUnregisterMatchTest, self())
       ["hello"]
@@ -791,7 +698,7 @@ defmodule Registry do
 
   For duplicate registries:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateUnregisterMatchTest)
+      iex> Registry.start_link(:duplicate, Registry.DuplicateUnregisterMatchTest)
       iex> Registry.register(Registry.DuplicateUnregisterMatchTest, "hello", :world_a)
       iex> Registry.register(Registry.DuplicateUnregisterMatchTest, "hello", :world_b)
       iex> Registry.register(Registry.DuplicateUnregisterMatchTest, "hello", :world_c)
@@ -803,9 +710,7 @@ defmodule Registry do
       ["hello", "hello"]
       iex> Registry.lookup(Registry.DuplicateUnregisterMatchTest, "hello")
       [{self(), :world_b}, {self(), :world_c}]
-
   """
-  @doc since: "1.5.0"
   def unregister_match(registry, key, pattern, guards \\ []) when is_list(guards) do
     self = self()
 
@@ -825,8 +730,7 @@ defmodule Registry do
     total = :ets.select_count(key_ets, total_spec)
 
     # We only want to delete things that match the pattern
-    delete_spec = [{{:_, {self, pattern}}, [underscore_guard | guards], [true]}]
-
+    delete_spec = [{{:_, {self, pattern}}, [underscore_guard | guards] ,[true]}]
     case :ets.select_delete(key_ets, delete_spec) do
       # We deleted everything, we can just delete the object
       ^total ->
@@ -882,7 +786,7 @@ defmodule Registry do
 
   Registering under a unique registry does not allow multiple entries:
 
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueRegisterTest)
+      iex> Registry.start_link(:unique, Registry.UniqueRegisterTest)
       iex> {:ok, _} = Registry.register(Registry.UniqueRegisterTest, "hello", :world)
       iex> Registry.register(Registry.UniqueRegisterTest, "hello", :later)
       {:error, {:already_registered, self()}}
@@ -891,14 +795,13 @@ defmodule Registry do
 
   Such is possible for duplicate registries though:
 
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateRegisterTest)
+      iex> Registry.start_link(:duplicate, Registry.DuplicateRegisterTest)
       iex> {:ok, _} = Registry.register(Registry.DuplicateRegisterTest, "hello", :world)
       iex> {:ok, _} = Registry.register(Registry.DuplicateRegisterTest, "hello", :world)
       iex> Registry.keys(Registry.DuplicateRegisterTest, self())
       ["hello", "hello"]
 
   """
-  @doc since: "1.4.0"
   @spec register(registry, key, value) :: {:ok, pid} | {:error, {:already_registered, pid}}
   def register(registry, key, value) when is_atom(registry) do
     self = self()
@@ -907,23 +810,19 @@ defmodule Registry do
     key_ets = key_ets || key_ets!(registry, key_partition)
     {pid_server, pid_ets} = pid_ets || pid_ets!(registry, pid_partition)
 
-    # Notice we write first to the pid_ets table because it will
-    # always be able to do the cleanup. If we register first to the
+    # Notice we write first to the pid ets table because it will
+    # always be able to do the clean up. If we register first to the
     # key one and the process crashes, the key will stay there forever.
     Process.link(pid_server)
     true = :ets.insert(pid_ets, {self, key, key_ets})
-
     case register_key(kind, pid_server, key_ets, key, {key, {self, value}}) do
       {:ok, _} = ok ->
         for listener <- listeners do
           Kernel.send(listener, {:register, registry, key, self, value})
         end
-
         ok
-
       {:error, {:already_registered, ^self}} = error ->
         error
-
       {:error, _} = error ->
         true = :ets.delete_object(pid_ets, {self, key, key_ets})
         unlink_if_unregistered(pid_server, pid_ets, self)
@@ -935,7 +834,6 @@ defmodule Registry do
     true = :ets.insert(key_ets, entry)
     {:ok, pid_server}
   end
-
   defp register_key(:unique, pid_server, key_ets, key, entry) do
     if :ets.insert_new(key_ets, entry) do
       {:ok, pid_server}
@@ -950,7 +848,6 @@ defmodule Registry do
             :ets.delete_object(key_ets, current)
             register_key(:unique, pid_server, key_ets, key, entry)
           end
-
         [] ->
           register_key(:unique, pid_server, key_ets, key, entry)
       end
@@ -964,21 +861,20 @@ defmodule Registry do
 
   ## Examples
 
-      iex> Registry.start_link(keys: :unique, name: Registry.MetaTest, meta: [custom_key: "custom_value"])
+      iex> Registry.start_link(:unique, Registry.MetaTest, meta: [custom_key: "custom_value"])
       iex> Registry.meta(Registry.MetaTest, :custom_key)
       {:ok, "custom_value"}
       iex> Registry.meta(Registry.MetaTest, :unknown_key)
       :error
 
   """
-  @doc since: "1.4.0"
   @spec meta(registry, meta_key) :: {:ok, meta_value} | :error
   def meta(registry, key) when is_atom(registry) and (is_atom(key) or is_tuple(key)) do
     try do
       :ets.lookup(registry, key)
     catch
       :error, :badarg ->
-        raise ArgumentError, "unknown registry: #{inspect(registry)}"
+        raise ArgumentError, "unknown registry: #{inspect registry}"
     else
       [{^key, value}] -> {:ok, value}
       _ -> :error
@@ -992,7 +888,7 @@ defmodule Registry do
 
   ## Examples
 
-      iex> Registry.start_link(keys: :unique, name: Registry.PutMetaTest)
+      iex> Registry.start_link(:unique, Registry.PutMetaTest)
       iex> Registry.put_meta(Registry.PutMetaTest, :custom_key, "custom_value")
       :ok
       iex> Registry.meta(Registry.PutMetaTest, :custom_key)
@@ -1003,7 +899,6 @@ defmodule Registry do
       {:ok, "tuple_value"}
 
   """
-  @doc since: "1.4.0"
   @spec put_meta(registry, meta_key, meta_value) :: :ok
   def put_meta(registry, key, value) when is_atom(registry) and (is_atom(key) or is_tuple(key)) do
     try do
@@ -1011,121 +906,7 @@ defmodule Registry do
       :ok
     catch
       :error, :badarg ->
-        raise ArgumentError, "unknown registry: #{inspect(registry)}"
-    end
-  end
-
-  @doc """
-  Returns the number of registered keys in a registry.
-  It runs in constant time.
-
-  ## Examples
-  In the example below we register the current process and ask for the
-  number of keys in the registry:
-
-      iex> Registry.start_link(keys: :unique, name: Registry.UniqueCountTest)
-      iex> Registry.count(Registry.UniqueCountTest)
-      0
-      iex> {:ok, _} = Registry.register(Registry.UniqueCountTest, "hello", :world)
-      iex> {:ok, _} = Registry.register(Registry.UniqueCountTest, "world", :world)
-      iex> Registry.count(Registry.UniqueCountTest)
-      2
-
-  The same applies to duplicate registries:
-
-      iex> Registry.start_link(keys: :duplicate, name: Registry.DuplicateCountTest)
-      iex> Registry.count(Registry.DuplicateCountTest)
-      0
-      iex> {:ok, _} = Registry.register(Registry.DuplicateCountTest, "hello", :world)
-      iex> {:ok, _} = Registry.register(Registry.DuplicateCountTest, "hello", :world)
-      iex> Registry.count(Registry.DuplicateCountTest)
-      2
-
-  """
-  @doc since: "1.7.0"
-  @spec count(registry) :: non_neg_integer()
-  def count(registry) when is_atom(registry) do
-    case key_info!(registry) do
-      {_kind, partitions, nil} ->
-        Enum.reduce(0..(partitions - 1), 0, fn partition_index, acc ->
-          acc + safe_size(key_ets!(registry, partition_index))
-        end)
-
-      {_kind, 1, key_ets} ->
-        safe_size(key_ets)
-    end
-  end
-
-  defp safe_size(ets) do
-    try do
-      :ets.info(ets, :size)
-    catch
-      :error, :badarg -> 0
-    end
-  end
-
-  @doc """
-  Returns the number of `{pid, value}` pairs under the given `key` in `registry`
-  that match `pattern`.
-
-  Pattern must be an atom or a tuple that will match the structure of the
-  value stored in the registry. The atom `:_` can be used to ignore a given
-  value or tuple element, while the atom `:"$1"` can be used to temporarily assign part
-  of pattern to a variable for a subsequent comparison.
-
-  Optionally, it is possible to pass a list of guard conditions for more precise matching.
-  Each guard is a tuple, which describes checks that should be passed by assigned part of pattern.
-  For example the `$1 > 1` guard condition would be expressed as the `{:>, :"$1", 1}` tuple.
-  Please note that guard conditions will work only for assigned variables like `:"$1"`, `:"$2"`, etc.
-  Avoid usage of special match variables `:"$_"` and `:"$$"`, because it might not work as expected.
-
-  Zero will be returned if there is no match.
-
-  For unique registries, a single partition lookup is necessary. For
-  duplicate registries, all partitions must be looked up.
-
-  ## Examples
-
-  In the example below we register the current process under the same
-  key in a duplicate registry but with different values:
-
-      iex> Registry.start_link(keys: :duplicate, name: Registry.CountMatchTest)
-      iex> {:ok, _} = Registry.register(Registry.CountMatchTest, "hello", {1, :atom, 1})
-      iex> {:ok, _} = Registry.register(Registry.CountMatchTest, "hello", {2, :atom, 2})
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {1, :_, :_})
-      1
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {2, :_, :_})
-      1
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {:_, :atom, :_})
-      2
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {:"$1", :_, :"$1"})
-      2
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {:_, :_, :"$1"}, [{:>, :"$1", 1}])
-      1
-      iex> Registry.count_match(Registry.CountMatchTest, "hello", {:_, :"$1", :_}, [{:is_atom, :"$1"}])
-      2
-
-  """
-  @doc since: "1.7.0"
-  @spec count_match(registry, key, match_pattern, guards) :: non_neg_integer()
-  def count_match(registry, key, pattern, guards \\ [])
-      when is_atom(registry) and is_list(guards) do
-    guards = [{:"=:=", {:element, 1, :"$_"}, {:const, key}} | guards]
-    spec = [{{:_, {:_, pattern}}, guards, [true]}]
-
-    case key_info!(registry) do
-      {:unique, partitions, key_ets} ->
-        key_ets = key_ets || key_ets!(registry, key, partitions)
-        :ets.select_count(key_ets, spec)
-
-      {:duplicate, 1, key_ets} ->
-        :ets.select_count(key_ets, spec)
-
-      {:duplicate, partitions, _key_ets} ->
-        Enum.reduce(0..(partitions - 1), 0, fn partition_index, acc ->
-          count = :ets.select_count(key_ets!(registry, partition_index), spec)
-          acc + count
-        end)
+        raise ArgumentError, "unknown registry: #{inspect registry}"
     end
   end
 
@@ -1142,7 +923,7 @@ defmodule Registry do
       :ets.lookup_element(registry, @all_info, 2)
     catch
       :error, :badarg ->
-        raise ArgumentError, "unknown registry: #{inspect(registry)}"
+        raise ArgumentError, "unknown registry: #{inspect registry}"
     end
   end
 
@@ -1151,7 +932,7 @@ defmodule Registry do
       :ets.lookup_element(registry, @key_info, 2)
     catch
       :error, :badarg ->
-        raise ArgumentError, "unknown registry: #{inspect(registry)}"
+        raise ArgumentError, "unknown registry: #{inspect registry}"
     end
   end
 
@@ -1182,7 +963,6 @@ defmodule Registry do
   defp partitions(:unique, key, pid, partitions) do
     {hash(key, partitions), hash(pid, partitions)}
   end
-
   defp partitions(:duplicate, _key, pid, partitions) do
     partition = hash(pid, partitions)
     {partition, partition}
@@ -1200,8 +980,7 @@ defmodule Registry.Supervisor do
   use Supervisor
 
   def start_link(kind, registry, partitions, listeners, entries) do
-    arg = {kind, registry, partitions, listeners, entries}
-    Supervisor.start_link(__MODULE__, arg, name: registry)
+    Supervisor.start_link(__MODULE__, {kind, registry, partitions, listeners, entries}, name: registry)
   end
 
   def init({kind, registry, partitions, listeners, entries}) do
@@ -1209,7 +988,7 @@ defmodule Registry.Supervisor do
     true = :ets.insert(registry, entries)
 
     children =
-      for i <- 0..(partitions - 1) do
+      for i <- 0..partitions - 1 do
         key_partition = Registry.Partition.key_name(registry, i)
         pid_partition = Registry.Partition.pid_name(registry, i)
         arg = {kind, registry, i, partitions, key_partition, pid_partition, listeners}
@@ -1233,7 +1012,7 @@ end
 defmodule Registry.Partition do
   @moduledoc false
 
-  # This process owns the equivalent key and pid ETS tables
+  # This process owns the equivalent key and pid ets tables
   # and is responsible for monitoring processes that map to
   # its own pid table.
   use GenServer
@@ -1276,11 +1055,9 @@ defmodule Registry.Partition do
     # If we have only one partition, we do an optimization which
     # is to write the table information alongside the registry info.
     if partitions == 1 do
-      entries = [
-        {@key_info, {kind, partitions, key_ets}},
-        {@all_info, {kind, partitions, key_ets, {self(), pid_ets}, listeners}}
-      ]
-
+      entries =
+        [{@key_info, {kind, partitions, key_ets}},
+         {@all_info, {kind, partitions, key_ets, {self(), pid_ets}, listeners}}]
       true = :ets.insert(registry, entries)
     else
       true = :ets.insert(registry, {i, key_ets, {self(), pid_ets}})
@@ -1294,25 +1071,14 @@ defmodule Registry.Partition do
   defp init_key_ets(:unique, key_partition) do
     :ets.new(key_partition, [:set, :public, read_concurrency: true, write_concurrency: true])
   end
-
   defp init_key_ets(:duplicate, key_partition) do
-    :ets.new(key_partition, [
-      :duplicate_bag,
-      :public,
-      read_concurrency: true,
-      write_concurrency: true
-    ])
+    :ets.new(key_partition, [:duplicate_bag, :public, read_concurrency: true, write_concurrency: true])
   end
 
   # A process can always have multiple keys, so the
   # pid partition is always a duplicate bag.
   defp init_pid_ets(_, pid_partition) do
-    :ets.new(pid_partition, [
-      :duplicate_bag,
-      :public,
-      read_concurrency: true,
-      write_concurrency: true
-    ])
+    :ets.new(pid_partition, [:duplicate_bag, :public, read_concurrency: true, write_concurrency: true])
   end
 
   def handle_call(:sync, _, state) do
@@ -1321,17 +1087,12 @@ defmodule Registry.Partition do
 
   def handle_info({:EXIT, pid, _reason}, ets) do
     entries = :ets.take(ets, pid)
-
     for {_pid, key, key_ets} <- entries do
-      key_ets =
-        case key_ets do
-          # In case the fake key_ets is being used. See unregister_match/2.
-          {key_ets, _} ->
-            key_ets
-
-          _ ->
-            key_ets
-        end
+      key_ets = case key_ets do
+        # In case the fake key ets is being used. See unregister_match/2.
+        {key_ets, _} -> key_ets
+        _ -> key_ets
+      end
 
       try do
         :ets.match_delete(key_ets, {key, {pid, :_}})
@@ -1339,7 +1100,9 @@ defmodule Registry.Partition do
         :error, :badarg -> :badarg
       end
     end
-
     {:noreply, ets}
   end
+  def handle_info(msg, state) do
+    super(msg, state)
+  end
 end

lib/elixir/lib/set.ex

@@ -1,34 +1,32 @@
 defmodule Set do
   @moduledoc ~S"""
-  Generic API for sets.
+  WARNING: this module is deprecated.
 
-  This module is deprecated, use the `MapSet` module instead.
+  Use the `MapSet` module instead.
   """
 
-  @moduledoc deprecated: "Use MapSet instead"
-
   @type value :: any
   @type values :: [value]
   @type t :: map
 
   # TODO: Remove by 2.0
-  message = "Use the MapSet module for working with sets"
+  # (hard-deprecated in elixir_dispatch)
 
   defmacrop target(set) do
     quote do
       case unquote(set) do
-        %module{} -> module
-        set -> unsupported_set(set)
+        %{__struct__: x} when is_atom(x) ->
+          x
+        x ->
+          unsupported_set(x)
       end
     end
   end
 
-  @deprecated message
   def delete(set, value) do
     target(set).delete(set, value)
   end
 
-  @deprecated message
   def difference(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -38,12 +36,10 @@ defmodule Set do
     else
       Enumerable.reduce(set2, {:cont, set1}, fn v, acc ->
         {:cont, target1.delete(acc, v)}
-      end)
-      |> elem(1)
+      end) |> elem(1)
     end
   end
 
-  @deprecated message
   def disjoint?(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -54,19 +50,17 @@ defmodule Set do
       Enumerable.reduce(set2, {:cont, true}, fn member, acc ->
         case target1.member?(set1, member) do
           false -> {:cont, acc}
-          _ -> {:halt, false}
+          _     -> {:halt, false}
         end
-      end)
-      |> elem(1)
+      end) |> elem(1)
     end
   end
 
-  @deprecated message
+  @doc false
   def empty(set) do
     target(set).empty(set)
   end
 
-  @deprecated message
   def equal?(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -83,7 +77,7 @@ defmodule Set do
     end
   end
 
-  @deprecated message
+
   def intersection(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -93,27 +87,24 @@ defmodule Set do
     else
       Enumerable.reduce(set1, {:cont, target1.new}, fn v, acc ->
         {:cont, if(target2.member?(set2, v), do: target1.put(acc, v), else: acc)}
-      end)
-      |> elem(1)
+      end) |> elem(1)
     end
   end
 
-  @deprecated message
+
   def member?(set, value) do
     target(set).member?(set, value)
   end
 
-  @deprecated message
+
   def put(set, value) do
     target(set).put(set, value)
   end
 
-  @deprecated message
   def size(set) do
     target(set).size(set)
   end
 
-  @deprecated message
   def subset?(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -125,12 +116,10 @@ defmodule Set do
     end
   end
 
-  @deprecated message
   def to_list(set) do
     target(set).to_list(set)
   end
 
-  @deprecated message
   def union(set1, set2) do
     target1 = target(set1)
     target2 = target(set2)
@@ -140,8 +129,7 @@ defmodule Set do
     else
       Enumerable.reduce(set2, {:cont, set1}, fn v, acc ->
         {:cont, target1.put(acc, v)}
-      end)
-      |> elem(1)
+      end) |> elem(1)
     end
   end
 
@@ -149,13 +137,12 @@ defmodule Set do
     Enumerable.reduce(set1, {:cont, true}, fn member, acc ->
       case target2.member?(set2, member) do
         true -> {:cont, acc}
-        _ -> {:halt, false}
+        _    -> {:halt, false}
       end
-    end)
-    |> elem(1)
+    end) |> elem(1)
   end
 
   defp unsupported_set(set) do
-    raise ArgumentError, "unsupported set: #{inspect(set)}"
+    raise ArgumentError, "unsupported set: #{inspect set}"
   end
 end

lib/elixir/lib/stream/reducers.ex

@@ -4,8 +4,7 @@ defmodule Stream.Reducers do
 
   def chunk_every(chunk_by, enumerable, count, step, leftover) do
     limit = :erlang.max(count, step)
-
-    chunk_fun = fn entry, {acc_buffer, acc_count} ->
+    chunk_by.(enumerable, {[], 0}, fn entry, {acc_buffer, acc_count} ->
       acc_buffer = [entry | acc_buffer]
       acc_count = acc_count + 1
 
@@ -22,44 +21,46 @@ defmodule Stream.Reducers do
       else
         {:cont, new_state}
       end
-    end
-
-    after_fun = fn {acc_buffer, acc_count} ->
-      if leftover == :discard or acc_count == 0 or acc_count >= count do
+    end, fn {acc_buffer, acc_count} ->
+      if leftover == :discard or acc_count == 0 or (step > count and acc_count >= count) do
         {:cont, []}
       else
         {:cont, :lists.reverse(acc_buffer, Enum.take(leftover, count - acc_count)), []}
       end
-    end
-
-    chunk_by.(enumerable, {[], 0}, chunk_fun, after_fun)
+    end)
   end
 
   def chunk_by(chunk_by, enumerable, fun) do
-    chunk_fun = fn
+    chunk_by.(enumerable, nil, fn
       entry, nil ->
         {:cont, {[entry], fun.(entry)}}
-
       entry, {acc, value} ->
         case fun.(entry) do
           ^value -> {:cont, {[entry | acc], value}}
           new_value -> {:cont, :lists.reverse(acc), {[entry], new_value}}
         end
-    end
-
-    after_fun = fn
+    end, fn
       nil -> {:cont, :done}
       {acc, _value} -> {:cont, :lists.reverse(acc), :done}
-    end
+    end)
+  end
 
-    chunk_by.(enumerable, nil, chunk_fun, after_fun)
+  defmacro chunk_while(callback, fun \\ nil) do
+    quote do
+      fn entry, acc(head, acc, tail) ->
+        case unquote(callback).(entry, acc) do
+          {:cont, emit, acc} -> next_with_acc(unquote(fun), emit, head, acc, tail)
+          {:cont, acc} -> skip(acc(head, acc, tail))
+          {:halt, acc} -> {:halt, acc(head, acc, tail)}
+        end
+      end
+    end
   end
 
   defmacro dedup(callback, fun \\ nil) do
     quote do
       fn entry, acc(head, prev, tail) = acc ->
         value = unquote(callback).(entry)
-
         case prev do
           {:value, ^value} -> skip(acc)
           _ -> next_with_acc(unquote(fun), entry, head, {:value, value}, tail)
@@ -73,7 +74,6 @@ defmodule Stream.Reducers do
       fn
         _entry, acc(head, amount, tail) when amount > 0 ->
           skip(acc(head, amount - 1, tail))
-
         entry, acc(head, amount, tail) ->
           next_with_acc(unquote(fun), entry, head, amount, tail)
       end
@@ -85,7 +85,6 @@ defmodule Stream.Reducers do
       fn
         entry, acc(head, curr, tail) when curr in [unquote(nth), :first] ->
           skip(acc(head, 1, tail))
-
         entry, acc(head, curr, tail) ->
           next_with_acc(unquote(fun), entry, head, curr + 1, tail)
       end
@@ -141,7 +140,6 @@ defmodule Stream.Reducers do
       fn
         entry, acc(head, curr, tail) when curr in [unquote(nth), :first] ->
           next_with_acc(unquote(fun), unquote(mapper).(entry), head, 1, tail)
-
         entry, acc(head, curr, tail) ->
           next_with_acc(unquote(fun), entry, head, curr + 1, tail)
       end
@@ -165,7 +163,6 @@ defmodule Stream.Reducers do
       fn
         entry, acc(head, :first, tail) ->
           next_with_acc(unquote(fun), entry, head, {:ok, entry}, tail)
-
         entry, acc(head, {:ok, acc}, tail) ->
           value = unquote(callback).(entry, acc)
           next_with_acc(unquote(fun), value, head, {:ok, value}, tail)
@@ -188,11 +185,9 @@ defmodule Stream.Reducers do
         case curr do
           0 ->
             {:halt, original}
-
           1 ->
             {_, acc} = next_with_acc(unquote(fun), entry, head, 0, tail)
             {:halt, acc}
-
           _ ->
             next_with_acc(unquote(fun), entry, head, curr - 1, tail)
         end
@@ -205,7 +200,6 @@ defmodule Stream.Reducers do
       fn
         entry, acc(head, curr, tail) when curr in [unquote(nth), :first] ->
           next_with_acc(unquote(fun), entry, head, 1, tail)
-
         entry, acc(head, curr, tail) ->
           skip(acc(head, curr + 1, tail))
       end
@@ -228,7 +222,6 @@ defmodule Stream.Reducers do
     quote do
       fn entry, acc(head, prev, tail) = original ->
         value = unquote(callback).(entry)
-
         if Map.has_key?(prev, value) do
           skip(original)
         else