Experimental lexer generator: Lex files with zeros properly.

tools/lexer_generator/rule_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 18 matching lines @@
 from automaton import Action
 from rule_lexer import RuleLexer
 from regex_parser import RegexParser
 from nfa_builder import NfaBuilder
 from dfa import Dfa
 from transition_keys import TransitionKey
 
 class RuleParserState:
 
   def __init__(self):
-    self.aliases = {
-      'eof' : RegexParser.parse("[\\0]"),
-    }
+    self.aliases = {}
     self.character_classes = {}
     self.current_state = None
     self.rules = {}
     self.transitions = set()
 
   def parse(self, string):
     return RuleParser.parse(string, self)
 
 class RuleParser:
 
@@ skipping 272 matching lines @@
     for k, v in parser_state.rules.items():
       if k == 'default': continue
       process(k, v)
     process('default', parser_state.rules['default'])
     # build the automata
     for rule_name, graph in rule_map.items():
       self.__automata[rule_name] = RuleProcessor.Automata(builder, graph)
     # process default_action
     default_action = parser_state.rules['default']['default_action']
     self.default_action = Action(None, default_action[1]) if default_action else None