Experimental parser: some support for adding subraphs

tools/lexer_generator/generator.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 62 matching lines @@
     loads.append(load_template % ("nfa [%s]" % name, nfa_i))
     loads.append(load_template % ("dfa [%s]" % name, dfa_i))
   body = "\n".join(scripts) + (load_outer_template % "\n".join(loads))
   return file_template % body
 
 def process_rules(parser_state):
   rule_map = {}
   builder = NfaBuilder()
   builder.set_character_classes(parser_state.character_classes)
   assert 'default' in parser_state.rules
-  for k, v in parser_state.rules.items():
+  def process(k, v):
     assert 'default' in v
     graphs = []
     for (graph, action) in v['regex']:
-      graphs.append(NfaBuilder.add_action(graph, action))
-    rule_map[k] = NfaBuilder.or_graphs(graphs)
+      (precedence, code, transition) = action
+      if code:
+        graph = NfaBuilder.add_action(graph, (precedence, code, None))
+      if transition == 'continue':
+        graph = NfaBuilder.add_continue(graph)
+      elif (transition == 'break' or
+            transition == 'terminate' or
+            transition == 'terminate_illegal'):
+        pass
+      else:
+        assert k == 'default'
+        graph = NfaBuilder.join_subgraph(graph, transition, rule_map[transition])
+      graphs.append(graph)
+    graph = NfaBuilder.or_graphs(graphs)
+    # merge default action
+    (precedence, code, transition) = v['default'][1]
+    assert transition == 'continue' or transition == 'break'
+    if code:
+      graph = NfaBuilder.add_incoming_action(graph, (precedence, code, None))
+    rule_map[k] = graph
+  for k, v in parser_state.rules.items():
+    if k == 'default': continue
+    process(k, v)
+  process('default', parser_state.rules['default'])
   html_data = []
   for rule_name, graph in rule_map.items():
     nfa = builder.nfa(graph)
     (start, dfa_nodes) = nfa.compute_dfa()
     dfa = Dfa(start, dfa_nodes)
     html_data.append((rule_name, nfa, dfa))
   return html_data
 
 if __name__ == '__main__':
 
   parser = argparse.ArgumentParser()
   parser.add_argument('--html')
+  parser.add_argument('--re', default='src/lexer/lexer_py.re')
   args = parser.parse_args()
 
-  re_file = 'src/lexer/lexer_py.re'
-
+  re_file = args.re
   parser_state = RuleParserState()
+  print "parsing %s" % re_file
   with open(re_file, 'r') as f:
     RuleParser.parse(f.read(), parser_state)
   html_data = process_rules(parser_state)
 
   html_file = args.html
   if html_file:
     html = generate_html(html_data)
     with open(args.html, 'w') as f:
       f.write(html)
       print "wrote html to %s" % html_file