Experimental parser: remove dead code.

tools/lexer_generator/nfa_builder.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 297 matching lines @@
 
   @staticmethod
   def add_continue(graph):
     return ('CONTINUE', graph)
 
   @staticmethod
   def catch_all():
     return ('CATCH_ALL',)
 
   @staticmethod
-  def epsilon():
-    return ('EPSILON',)
-
-  @staticmethod
   def join_subgraph(graph, name, subgraph):
     return ('JOIN', graph, name, subgraph)
 
   @staticmethod
   def or_graphs(graphs):
     return reduce(lambda acc, g: ('OR', acc, g), graphs)
 
   @staticmethod
   def cat_graphs(graphs):
     return reduce(lambda acc, g: ('CAT', acc, g), graphs)
 
   __modifer_map = {
     '+': 'ONE_OR_MORE',
     '?': 'ZERO_OR_ONE',
     '*': 'ZERO_OR_MORE',
   }
 
   @staticmethod
   def apply_modifier(modifier, graph):
     return (NfaBuilder.__modifer_map[modifier], graph)