Splice nested binaries with default types and size

Author: José Valim

lib/elixir/src/elixir_literal.erl

@@ -94,9 +94,16 @@ build_bitstr_each(Fun, [H|T], Meta, S, Acc) ->
 
 build_bitstr_each(Fun, T, Meta, S, Acc, H, Size, Types) ->
   { Expr, NS } = Fun(H, S),
-  case (is_default_or_utf(Types) andalso Expr) of
-    { bin, _,[{ bin_element, 0, { string, 0, String }, default, default }] } ->
+
+  AllowString = types_allow_string(Types),
+  AllowSplice = types_allow_splice(Types),
+  AllowAny    = (AllowString orelse AllowSplice) andalso (Size == default),
+
+  case AllowAny andalso Expr of
+    { bin, _, [{ bin_element, 0, { string, 0, String }, default, default }] } when AllowString ->
       build_bitstr_each(Fun, T, Meta, NS, [{ bin_element, ?line(Meta), { string, 0, String }, Size, Types }|Acc]);
+    { bin, _, Elements } when AllowSplice ->
+      build_bitstr_each(Fun, T, Meta, NS, lists:reverse(Elements) ++ Acc);
     { cons, _, _, _ } = Cons ->
       build_bitstr_each(Fun, T, Meta, NS, rehash_cons(Cons, Size, Types, []) ++ Acc);
     { nil, _ } ->
@@ -109,10 +116,15 @@ rehash_cons({ nil, _ }, _Size, _Types, Acc) -> Acc;
 rehash_cons({ cons, Line, Left, Right }, Size, Types, Acc) ->
   rehash_cons(Right, Size, Types, [{ bin_element, Line, Left, Size, Types }|Acc]).
 
-is_default_or_utf(default) -> true;
-is_default_or_utf([UTF|_]) when UTF == utf8; UTF == utf16; UTF == utf32 -> true;
-is_default_or_utf([_|T]) -> is_default_or_utf(T);
-is_default_or_utf([]) -> false.
+types_allow_string([End|T]) when End == little; End == big -> types_allow_string(T);
+types_allow_string([UTF|T]) when UTF == utf8; UTF == utf16; UTF == utf32 -> types_allow_string(T);
+types_allow_string([]) -> true;
+types_allow_string(_) -> false.
+
+types_allow_splice(default) -> true;
+types_allow_splice([binary]) -> true;
+types_allow_splice([bitstring]) -> true;
+types_allow_splice(_) -> false.
 
 %% Extra bitstring specifiers
 

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

@@ -96,13 +96,19 @@ bar
     assert <<_a, _b :: size(s)>> = "foo"
   end
 
+  test :pattern_match_with_splice do
+    assert << 1, <<2, 3, 4>>, 5 >> = <<1, 2, 3, 4, 5>>
+  end
+
   test :partial_application do
     assert (<< &1, 2 >>).(1) == << 1, 2 >>
     assert (<< &1, &2 >>).(1, 2) == << 1, 2 >>
     assert (<< &2, &1 >>).(2, 1) == << 1, 2 >>
   end
 
-  test :bitsyntax_with_utf do
+  test :literal do
+    assert <<106, 111, 115, 101>> == << "jose" :: binary >>
+
     assert <<106, 111, 115, 101>> == << "jose" :: utf8 >>
     assert <<106, 111, 115, 101>> == << 'jose' :: utf8 >>