Experimental lexer generator: parse \000 etc. inside char classes.

tools/lexer_generator/regex_lexer.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 35 matching lines @@
     'REPEAT_BEGIN',
     'REPEAT_END',
 
     'NUMBER',
     'COMMA',
     'LITERAL',
 
     'RANGE',
     'NOT',
     'CLASS_LITERAL',
+    'CLASS_LITERAL_AS_OCTAL',
     'CHARACTER_CLASS',
   )
 
   states = (
     ('class','exclusive'),
     ('repeat','exclusive'),
   )
 
   def t_ESCAPED_LITERAL(self, t):
     r'\\\(|\\\)|\\\[|\\\]|\\\||\\\+|\\\*|\\\?|\\\.|\\\\|\\\{|\\\}'
@@ skipping 20 matching lines @@
 
   def t_class_CLASS_END(self, t):
     r'\]'
     self.lexer.pop_state()
     return t
 
   t_class_RANGE = '-'
   t_class_NOT = '\^'
   t_class_CHARACTER_CLASS = r':\w+:'
 
+  def t_class_CLASS_LITERAL_AS_OCTAL(self, t):
+    r'\\\d+'
+    return t
+
   def t_class_ESCAPED_CLASS_LITERAL(self, t):
     r'\\\^|\\-|\\\[|\\\]|\\\:|\\\w'
     t.type = 'CLASS_LITERAL'
     t.value = t.value[1:]
     return t
 
-  t_class_CLASS_LITERAL = r'[\w $_+]' # fix this
+  t_class_CLASS_LITERAL = r'[\w $_+]'
 
   def t_REPEAT_BEGIN(self, t):
     r'\{'
     self.lexer.push_state('repeat')
     return t
 
   def t_repeat_REPEAT_END(self, t):
     r'\}'
     self.lexer.pop_state()
     return t
 
   t_repeat_NUMBER = r'[0-9]+'
   t_repeat_COMMA = r','
 
   t_ANY_ignore  = '\n'
 
   def t_ANY_error(self, t):
     raise Exception("Illegal character '%s'" % t.value[0])
 
   def build(self, **kwargs):
     self.lexer = lex.lex(module=self, **kwargs)