Improve error messages when there is a space in between function name and parenthesis

Author: José Valim

lib/elixir/src/elixir_aliases.erl

@@ -68,7 +68,7 @@ expand_one(H, Aliases) ->
 ensure_loaded(Line, Ref, S) ->
   ensure_loaded(Line, S#elixir_scope.file, Ref, S#elixir_scope.context_modules).
 
-ensure_loaded(_Line, _File, 'Elixir.Kernel', FileModules) ->
+ensure_loaded(_Line, _File, 'Elixir.Kernel', _FileModules) ->
   ok;
 
 ensure_loaded(Line, File, Ref, FileModules) ->

lib/elixir/src/elixir_parser.yrl

@@ -10,7 +10,8 @@ Nonterminals
   open_curly close_curly
   open_bit close_bit
   base_comma_expr comma_expr optional_comma_expr matched_comma_expr
-  call_args call_args_parens call_args_parens_not_one call_args_no_parens parens_call
+  call_args call_args_parens parens_call
+  call_args_no_parens call_args_no_parens_strict call_args_parens_not_one
   stab stab_eol stab_op stab_expr stab_maybe_expr
   kw_eol kw_expr kw_comma kw_base
   matched_kw_expr matched_kw_comma matched_kw_base
@@ -142,16 +143,16 @@ matched_op_expr -> comp_expr_op matched_expr : { '$1', '$2' }.
 
 block_expr -> parens_call call_args_parens do_block : build_identifier('$1', '$2' ++ '$3').
 block_expr -> parens_call call_args_parens call_args_parens do_block : build_nested_parens('$1', '$2', '$3' ++ '$4').
-block_expr -> dot_punctuated_identifier call_args_no_parens do_block : build_identifier('$1', '$2' ++ '$3').
+block_expr -> dot_punctuated_identifier call_args_no_parens_strict do_block : build_identifier('$1', '$2' ++ '$3').
 block_expr -> dot_do_identifier do_block : build_identifier('$1', '$2').
-block_expr -> dot_identifier call_args_no_parens do_block : build_identifier('$1', '$2' ++ '$3').
+block_expr -> dot_identifier call_args_no_parens_strict do_block : build_identifier('$1', '$2' ++ '$3').
 
 fn_expr -> fn_eol stab end_eol : build_fn('$1', build_stab(lists:reverse('$2'))).
 fn_expr -> call_expr : '$1'.
 
-call_expr -> dot_punctuated_identifier call_args_no_parens : build_identifier('$1', '$2').
-call_expr -> dot_op_identifier call_args_no_parens : build_identifier('$1', '$2').
-call_expr -> dot_identifier call_args_no_parens : build_identifier('$1', '$2').
+call_expr -> dot_punctuated_identifier call_args_no_parens_strict : build_identifier('$1', '$2').
+call_expr -> dot_op_identifier call_args_no_parens_strict : build_identifier('$1', '$2').
+call_expr -> dot_identifier call_args_no_parens_strict : build_identifier('$1', '$2').
 call_expr -> dot_punctuated_identifier : build_identifier('$1', []).
 call_expr -> dot_do_identifier : build_identifier('$1', nil).
 call_expr -> var : build_identifier('$1', nil).
@@ -388,6 +389,11 @@ parens_call -> matched_expr dot_call_op : { '.', [{line,?line('$2')}], ['$1'] }.
 matched_comma_expr -> matched_expr : ['$1'].
 matched_comma_expr -> matched_comma_expr ',' matched_expr : ['$3'|'$1'].
 
+call_args_no_parens_strict -> call_args_no_parens : '$1'.
+call_args_no_parens_strict -> open_paren ')' : throw_no_parens_strict('$1').
+call_args_no_parens_strict -> open_paren matched_kw_base close_paren : throw_no_parens_strict('$1').
+call_args_no_parens_strict -> open_paren matched_expr ',' call_args_no_parens close_paren : throw_no_parens_strict('$1').
+
 call_args_no_parens -> matched_comma_expr : lists:reverse('$1').
 call_args_no_parens -> matched_kw_base : ['$1'].
 call_args_no_parens -> matched_comma_expr ',' matched_kw_base : lists:reverse(['$3'|'$1']).
@@ -584,3 +590,13 @@ build_stab([H|T], Marker, Temp, Acc) ->
 build_stab([], Marker, Temp, Acc) ->
   H = { Marker, build_block(lists:reverse(Temp)) },
   lists:reverse([H|Acc]).
+
+%% Errors
+
+throw(Line, Error, Token) ->
+  throw({ error, { Line, ?MODULE, [Error, Token] }}).
+
+throw_no_parens_strict(Token) ->
+  throw(?line(Token), "invalid comma inside parenthesis. If you are making a "
+    "function call, do not insert spaces in between the function name and the "
+    "opening parentheses. Syntax error before: ", ")").

lib/elixir/src/elixir_translator.erl

@@ -14,9 +14,11 @@
 forms(String, StartLine, File, Opts) ->
   try elixir_tokenizer:tokenize(String, StartLine, [{ file, File }|Opts]) of
     { ok, Tokens } ->
-      case elixir_parser:parse(Tokens) of
+      try elixir_parser:parse(Tokens) of
         { ok, Forms } -> { ok, Forms };
         { error, { Line, _, [Error, Token] } } -> { error, { Line, Error, Token } }
+      catch
+        { error, { Line, _, [Error, Token] } } -> { error, { Line, Error, Token } }
       end;
     { error, { _, _, _ } } = Else -> Else
   catch

lib/elixir/test/elixir/kernel/errors_test.exs

@@ -43,6 +43,12 @@ defmodule Kernel.ErrorsTest do
     assert "nofile:1: syntax error before: '.'" == format_rescue '+.foo'
   end
 
+  test :syntax_error_on_parens_call do
+    assert "nofile:1: invalid comma inside parenthesis. If you are making a function call, " <>
+           "do not insert spaces in between the function name and the opening parentheses. " <>
+           "Syntax error before: )" == format_rescue 'foo (hello, world)'
+  end
+
   test :syntax_error_with_no_token do
     assert "nofile:1: missing terminator: ) (for \"(\" starting at line 1)" == format_rescue 'case 1 ('
   end

lib/elixir/test/erlang/translator_test.erl

@@ -107,7 +107,7 @@ oror_test() ->
   false = eval([{'||', [{line,1}], [false, false]}]),
   true  = eval([{'||', [{line,1}], [true, {error, [{line,1}], [omg]}]}]).
 
-%% Method calls
+%% Function calls
 
 local_call_test() ->
   42.0 = eval([{float, [{line,1}], [42]}]).