diff --git a/parso/grammar.py b/parso/grammar.py
index a03ec8f..15a1361 100644
--- a/parso/grammar.py
+++ b/parso/grammar.py
@@ -16,9 +16,11 @@ _loaded_grammars = {}
 
 class Grammar(object):
     """
+    Create custom grammars by calling this. It's not really supported, yet.
+
     :param text: A BNF representation of your grammar.
     """
-    def __init__(self, text, tokenizer=generate_tokens, parser=BaseParser,
+    def __init__(self, text, parser=BaseParser, tokenizer=generate_tokens,
                  diff_parser=None):
         self._pgen_grammar = generate_grammar(text)
         self._parser = parser