Expand macros and quoted variables inside << >>, closes #1063

Author: José Valim

lib/elixir/src/elixir_literal.erl

@@ -96,37 +96,28 @@ build_bitstr_each(Fun, [{'::',_,[H,V]}|T], Meta, S, Acc) ->
 build_bitstr_each(Fun, [H|T], Meta, S, Acc) ->
   build_bitstr_each(Fun, T, Meta, S, Acc, H, default, default).
 
-build_bitstr_each(Fun, T, Meta, S, Acc, H, Size, Types) when is_list(H) ->
-  case is_default_or_utf(Types) of
-    true ->
-      { NewAcc, NewS } = lists:foldl(fun(L, { LA, LS }) ->
-        { FL, FS } = Fun(L, LS),
-        { [{ bin_element, ?line(Meta), FL, Size, Types }|LA], FS }
-      end, { Acc, S }, H),
-      build_bitstr_each(Fun, T, Meta, NewS, NewAcc);
-    false ->
-      build_bitstr_default(Fun, T, Meta, S, Acc, H, Size, Types)
-  end;
+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, _, BinElements } ->
+      build_bitstr_each(Fun, T, Meta, NS, rehash_bin_elements(BinElements, Size, Types, []) ++ Acc);
+    { cons, _, _, _ } = Cons ->
+      build_bitstr_each(Fun, T, Meta, NS, rehash_cons(Cons, Size, Types, []) ++ Acc);
+    { nil, _ } ->
+      build_bitstr_each(Fun, T, Meta, NS, Acc);
+    _ ->
+      build_bitstr_each(Fun, T, Meta, NS, [{ bin_element, ?line(Meta), Expr, Size, Types }|Acc])
+  end.
 
-build_bitstr_each(Fun, T, Meta, S, Acc, H, Size, Types) when is_bitstring(H) ->
-  case is_default_or_utf(Types) of
-    true ->
-      Line = ?line(Meta),
-      { bin, _, Elements } = elixir_tree_helpers:elixir_to_erl(H),
-      NewAcc = lists:foldl(fun({ bin_element, _, Expr, _, _ }, FinalAcc) ->
-        [{ bin_element, Line, Expr, Size, Types }|FinalAcc]
-      end, Acc, Elements),
-      build_bitstr_each(Fun, T, Meta, S, NewAcc);
-    false ->
-      build_bitstr_default(Fun, T, Meta, S, Acc, H, Size, Types)
-  end;
+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]).
 
-build_bitstr_each(Fun, T, Meta, S, Acc, H, Size, Types) ->
-  build_bitstr_default(Fun, T, Meta, S, Acc, H, Size, Types).
+rehash_bin_elements([{ bin_element, Line, Expr, _S, _T }|T], Size, Types, Acc) ->
+  rehash_bin_elements(T, Size, Types, [{ bin_element, Line, Expr, Size, Types }|Acc]);
 
-build_bitstr_default(Fun, T, Meta, S, Acc, H, Size, Types) ->
-  { Expr, NS } = Fun(H, S),
-  build_bitstr_each(Fun, T, Meta, NS, [{ bin_element, ?line(Meta), Expr, Size, Types }|Acc]).
+rehash_bin_elements([], _Size, _Types, Acc) ->
+  Acc.
 
 is_default_or_utf(default) -> true;
 is_default_or_utf([UTF|_]) when UTF == utf8; UTF == utf16; UTF == utf32 -> true;

lib/elixir/test/elixir/binary_test.exs

@@ -98,6 +98,14 @@ bar
     assert <<0,0,0,106,0,0,0,111,0,0,0,115,0,0,0,101>> == << 'jose' :: utf32 >>
   end
 
+  @binary   "new "
+  @charlist 'old '
+
+  test :bitsyntax_with_expansion do
+    assert <<@binary, "world">> == "new world"
+    assert <<@charlist, "world">> == "old world"
+  end
+
   test :bitsyntax_translation do
     refb = "sample"
     sec_data = "another"