Experimental parser: visualize rule trees.

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 228 matching lines @@
     except Exception:
       RuleParser.__static_instance = None
       raise
     parser.__state = None
     assert parser_state.transitions <= set(parser_state.rules.keys())
 
 class RuleProcessor(object):
 
   def __init__(self, parser_state):
     self.__automata = {}
+    self.__rule_trees = {}
     self.__process_parser_state(parser_state)
 
   @staticmethod
   def parse(string, encoding_name):
     parser_state = RuleParserState(KeyEncoding.get(encoding_name))
     RuleParser.parse(string, parser_state)
     return RuleProcessor(parser_state)
 
   def automata_iter(self):
     return iter(self.__automata.items())
 
   def default_automata(self):
     return self.__automata['default']
 
+  def rule_tree_dots(self):
+    result = {}
+    for rule in self.__rule_trees:
+      result[rule] = NfaBuilder.rule_tree_dot(self.__rule_trees[rule])
+    return result
+
   class Automata(object):
 
     def __init__(self, builder, graph):
       self.__builder = builder
       self.__graph = graph
       self.__nfa = None
       self.__dfa = None
       self.__minimial_dfa = None
 
     def nfa(self):
@@ skipping 48 matching lines @@
       graph = NfaBuilder.or_graphs(graphs)
       rule_map[subgraph] = graph
     # process first the subgraphs, then the default graph
     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)
+      self.__rule_trees[rule_name] = 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