Experimental lexer generator: parse {} in regexps.

tools/lexer_generator/regex_parser.py

 # Copyright 2013 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 46 matching lines @@
     else:
       p[0] = self.__cat(p[1], p[2])
 
   def p_fragment(self, p):
     '''fragment : literal maybe_modifier
                 | class maybe_modifier
                 | group maybe_modifier
                 | any maybe_modifier
     '''
     if p[2] != None:
-      p[0] = (p[2], p[1])
+      if isinstance(p[2], tuple) and p[2][0] == 'REPEAT':
+        p[0] = (p[2][0], p[2][1], p[2][2], p[1])
+      else:
+        p[0] = (p[2], p[1])
     else:
       p[0] = p[1]
 
   def p_maybe_modifier(self, p):
     '''maybe_modifier : ONE_OR_MORE
                       | ZERO_OR_ONE
                       | ZERO_OR_MORE
+                      | repetition
                       | empty'''
     p[0] = p[1]
-    if p[1] != None:
+    if p[1] in self.token_map:
       p[0] = self.token_map[p[1]]
 
+  def p_repetition(self, p):
+    '''repetition : REPEAT_BEGIN NUMBER REPEAT_END
+                  | REPEAT_BEGIN NUMBER COMMA NUMBER REPEAT_END'''
+    if len(p) == 4:
+      p[0] = ("REPEAT", p[2], p[2])
+    else:
+      p[0] = ("REPEAT", p[2], p[4])
+
   def p_literal(self, p):
     '''literal : LITERAL'''
     p[0] = ('LITERAL', p[1])
 
   def p_any(self, p):
     '''any : ANY'''
     p[0] = (self.token_map[p[1]],)
 
   def p_class(self, p):
     '''class : CLASS_BEGIN class_content CLASS_END
@@ skipping 41 matching lines @@
   def build(self, **kwargs):
     self.parser = yacc.yacc(module=self, debug=0, write_tables=0, **kwargs)
     self.lexer = RegexLexer()
     self.lexer.build(**kwargs)
 
   @staticmethod
   def parse(data):
     parser = RegexParser()
     parser.build()
     return parser.parser.parse(data, lexer=parser.lexer.lexer)