Experimental parser: build regex parse trees for all rules

tools/lexer_generator/nfa.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 196 matching lines @@
     return ('ACTION', graph, action)
 
   @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)
+
 class Nfa:
 
   def __init__(self, start, end, nodes_created):
     self.__start = start
     self.__end = end
     self.__epsilon_closure_computed = False
     self.__verify(nodes_created)
 
   @staticmethod
   def __visit_edges(edge, compute_next_edge, visitor, state):
@@ skipping 101 matching lines @@
 digraph finite_state_machine {
   rankdir=LR;
   node [shape = circle, style=filled, bgcolor=lightgrey]; S_%s
   node [shape = doublecircle, style=unfilled]; S_%s
   node [shape = circle];
 %s
 }
     ''' % (self.__start.node_number(),
            self.__end.node_number(),
            "\n".join(node_content))