From 152c784a075bcad4e8a74ac3a8a17dd71f0bb472 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@plataformatec.com.br>
Date: Tue, 24 Jul 2012 13:04:33 +0200
Subject: [PATCH] Add binary_part to the list of guard functions

---
 lib/elixir/lib/kernel.ex             | 21 +++++++++++++++++++++
 lib/elixir/src/elixir_def.erl        |  4 ++--
 lib/elixir/src/elixir_dispatch.erl   |  4 +---
 lib/elixir/test/elixir/code_test.exs |  2 +-
 4 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/elixir/lib/kernel.ex b/lib/elixir/lib/kernel.ex
index 76224bb1df..4972a65466 100644
--- a/lib/elixir/lib/kernel.ex
+++ b/lib/elixir/lib/kernel.ex
@@ -352,6 +352,27 @@ defmodule Kernel do
   @spec atom_to_list(atom), do: list
   defmacro atom_to_list(atom)
 
+  @doc """
+  Extracts the part of the binary starting at `start` with length `length`.
+  Binaries are zero-indexed.
+
+  If start or length references in any way outside the binary, an
+  `ArgumentError` exception is raised.
+
+  Allowed in guard tests.
+
+  ## Examples
+
+      binary_part "foo", 1, 2 #=> "oo"
+
+  A negative length can be used to extract bytes at the end of a binary:
+
+      binary_part "foo", 3, -1 #=> 1
+
+  """
+  @spec binary_part(binary, pos_integer, integer), do: binary
+  defmacro binary_part(binary, start, length)
+
   @doc """
   Returns the atom whose text representation is `binary`. If `encoding` is latin1,
   no translation of bytes in the binary is done. If `encoding` is utf8 or unicode,
diff --git a/lib/elixir/src/elixir_def.erl b/lib/elixir/src/elixir_def.erl
index 41e1f3ebbd..68b423412f 100644
--- a/lib/elixir/src/elixir_def.erl
+++ b/lib/elixir/src/elixir_def.erl
@@ -257,7 +257,7 @@ store_each(Check, Kind, File, Location, Stack, Table, Defaults, {function, Line,
       FinalDefaults = Defaults + StoredDefaults,
       FinalClauses  = Clauses ++ StoredClauses,
       check_valid_kind(Line, File, Name, Arity, Kind, StoredKind),
-      check_valid_defaults(Line, File, Name, Arity, Defaults),
+      check_valid_defaults(Line, File, Name, Arity, FinalDefaults),
       Check andalso (Stack == StoredStack) andalso check_valid_clause(Line, File, Name, Arity, Table);
     [] ->
       FinalLocation = Location,
@@ -297,7 +297,7 @@ add_to_guards(Line, Expr, Clauses) ->
 %% Format errors
 
 format_error({clauses_with_docs,{Name,Arity}}) ->
-  io_lib:format("function ~s/~B has default values and multiple clauses, it is recommended to use a separate clause for declaring defaults", [Name, Arity]);
+  io_lib:format("function ~s/~B has default values and multiple clauses, use a separate clause for declaring defaults", [Name, Arity]);
 
 format_error({private_doc,{Name,Arity}}) ->
   io_lib:format("function ~s/~B is private, @doc's are always discarded for private functions", [Name, Arity]);
diff --git a/lib/elixir/src/elixir_dispatch.erl b/lib/elixir/src/elixir_dispatch.erl
index 91023a8211..d227ab6caa 100644
--- a/lib/elixir/src/elixir_dispatch.erl
+++ b/lib/elixir/src/elixir_dispatch.erl
@@ -254,9 +254,7 @@ in_erlang_functions() ->
     { abs, 1 },
     { atom_to_binary, 2 },
     { atom_to_list, 1 },
-    % Those are allowed in guard clauses, so we need to bring them back.
-    % { binary_part, 2 },
-    % { binary_part, 3 },
+    { binary_part, 3 },
     { binary_to_atom, 2 },
     { binary_to_existing_atom, 2 },
     { binary_to_list, 1 },
diff --git a/lib/elixir/test/elixir/code_test.exs b/lib/elixir/test/elixir/code_test.exs
index d9e3c11ab6..3706dfaf69 100644
--- a/lib/elixir/test/elixir/code_test.exs
+++ b/lib/elixir/test/elixir/code_test.exs
@@ -70,6 +70,6 @@ defmodule CodeTest do
 
   test :compile_info_returned_with_source_accessible_through_keyword_module do
     compile = __MODULE__.__info__(:compile)
-    refute_nil Keyword.get(compile, :source)
+    assert Keyword.get(compile, :source) != nil
   end
 end