Experimental parser: move code gen to own class

tools/lexer_generator/dfa.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 38 matching lines @@
   def actions(self):
     return self.__actions
 
   def add_transition(self, key, state):
     assert not self.__transitions.has_key(key)
     self.__transitions[key] = state
 
   def transitions(self):
     return self.__transitions
 
-  def to_code(self, start_node_number):
-    # FIXME: add different check types (if, switch, lookup table)
-    # FIXME: add action + break / continue
-    # FIXME: add default action
-    code = '''
-code_%s:
-    fprintf(stderr, "state %s\\n");''' % (self.node_number(), self.node_number())
-
-    action = self.action()
-    if action:
-      if action[1] == 'terminate':
-        code += 'return 0;'
-        return code
-      elif action[1] == 'terminate_illegal':
-        code += 'return 1;'
-        return code
-
-    code += '''
-    yych = *(++cursor_);
-    fprintf(stderr, "char at hand is %c (%d)\\n", yych, yych);\n'''
-
-    for key, state in self.__transitions.items():
-      code += key.to_code()
-      code += ''' {
-        goto code_%s;
-    }
-''' % state.node_number()
-
-    if action:
-      code += '%s\nyych = *(--cursor_);\ngoto code_%s;\n' % (self.action()[1], start_node_number)
-
-    return code
-
 class Dfa(Automaton):
 
   def __init__(self, start_name, mapping):
     super(Dfa, self).__init__()
     self.__terminal_set = set()
     self.__name_map = {}
     for i, (name, node_data) in enumerate(mapping.items()):
       node = DfaState(name, i, node_data['actions'])
       self.__name_map[name] = node
       if node_data['terminal']:
         self.__terminal_set.add(node)
     for name, node_data in mapping.items():
       node = self.__name_map[name]
       inversion = {}
       for key, state in node_data['transitions'].items():
         if not state in inversion:
           inversion[state] = []
         inversion[state].append(key)
       for state, keys in inversion.items():
         merged_key = TransitionKey.merged_key(keys)
         node.add_transition(merged_key, self.__name_map[state])
     self.__start = self.__name_map[start_name]
     assert self.__terminal_set
 
+  def start_state(self):
+    return self.__start
+
   def start_set(self):
     return set([self.__start])
 
   def terminal_set(self):
     return set(self.__terminal_set)
 
+  def all_states_iter(self):
+    return iter(self.__name_map.values())
+
   @staticmethod
   def __match_char(state, char):
     match = list(state.state_iter(key_filter = lambda k: k.matches_char(char)))
     if not match: return None
     assert len(match) == 1
     return match[0]
 
   def collect_actions(self, string):
     state = self.__start
     for c in string:
@@ skipping 23 matching lines @@
         last_position = pos
         # lex next token
         next = Dfa.__match_char(self.__start, c)
         assert next
       state = next
     assert state.action() # must invoke default action here
     yield (state.action()[1], last_position, len(string))
 
   def minimize(self):
     pass
-
-  def to_code(self):
-    code = '''
-YYCTYPE yych = *cursor_;
-goto code_%s;
-''' % (self.__start.node_number())
-    for n in self.__name_map.values():
-      code += n.to_code(self.__start.node_number())
-    return code