Experimental lexer generator: escaping fix

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 68 matching lines @@
 
   def t_class_CLASS_END(self, t):
     r'\]'
     self.lexer.pop_state()
     return t
 
   t_class_RANGE = '-'
   t_class_NOT = '\^'
 
   def t_class_ESCAPED_CLASS_LITERAL(self, t):
-    r'\\\^|\\-'
+    r'\\\^|\\-|\\\[|\\\]'
     t.type = 'CLASS_LITERAL'
     t.value = t.value[1:]
     return t
 
   t_class_CLASS_LITERAL = r'[a-zA-Z]' # fix this
 
   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)