diff --git a/lib/message_format/parser.rb b/lib/message_format/parser.rb
index 79d22e5..5b866c9 100644
--- a/lib/message_format/parser.rb
+++ b/lib/message_format/parser.rb
@@ -181,7 +181,7 @@ def parse_arg_id ()
       id = ''
       while @index < @length
         char = @pattern[@index]
-        if char == '{' or char == '#'
+        if char == '{' or char == '#' or char == '.' or char == '(' or char == ')'
           raise_expected('argument id')
         end
         if char == '}' or char == ',' or is_whitespace(char)