Handle more types on bitsyntax.

Author: José Valim

lib/elixir/lib/kernel/special_forms.ex

@@ -90,7 +90,11 @@ defmodule Kernel.SpecialForms do
   is an arbitrary series of bits. A binary is a special case of
   bitstring that has a total size divisible by 8.
 
-  The utf8, utf16, and utf32 types are for UTF code points.
+  The utf8, utf16, and utf32 types are for UTF code points. They
+  can also be applied to literal strings and char lists:
+
+      iex> <<"foo" :: utf16>>.
+      <<0,102,0,111,0,111>>
 
   The bits type is an alias for bitstring. The bytes type is an
   alias for binary.

lib/elixir/src/elixir_literal.erl

@@ -122,7 +122,9 @@ types_allow_string([]) -> true;
 types_allow_string(_) -> false.
 
 types_allow_splice(default) -> true;
+types_allow_splice([bytes]) -> true;
 types_allow_splice([binary]) -> true;
+types_allow_splice([bits]) -> true;
 types_allow_splice([bitstring]) -> true;
 types_allow_splice(_) -> false.
 

lib/elixir/test/elixir/kernel/binary_test.exs

@@ -108,6 +108,9 @@ bar
 
   test :literal do
     assert <<106, 111, 115, 101>> == << "jose" :: binary >>
+    assert <<106, 111, 115, 101>> == << "jose" :: bits >>
+    assert <<106, 111, 115, 101>> == << "jose" :: bitstring >>
+    assert <<106, 111, 115, 101>> == << "jose" :: bytes >>
 
     assert <<106, 111, 115, 101>> == << "jose" :: utf8 >>
     assert <<106, 111, 115, 101>> == << 'jose' :: utf8 >>
@@ -122,6 +125,20 @@ bar
     assert <<0, 0, 0, 106, 0, 0, 0, 111, 0, 0, 0, 115, 0, 0, 0, 101>> == << 'jose' :: utf32 >>
   end
 
+  test :literal_errors do
+    assert_raise ArgumentError, fn ->
+      Code.eval_string(%b[<< "foo" :: integer >>])
+    end
+
+    assert_raise ArgumentError, fn ->
+      Code.eval_string(%b[<< "foo" :: float >>])
+    end
+
+    assert_raise ArgumentError, fn ->
+      Code.eval_string(%b[<< 'foo' :: binary >>])
+    end
+  end
+
   @binary   "new "
   @charlist 'old '