Revision: 19312
Author: [email protected]
Date: Wed Feb 12 09:23:12 2014 UTC
Log: Experimental parser: make nfa nodes immutable
[email protected]
BUG=
Review URL: https://codereview.chromium.org/148293022
http://code.google.com/p/v8/source/detail?r=19312
Modified:
/branches/experimental/parser/tools/lexer_generator/nfa.py
/branches/experimental/parser/tools/lexer_generator/nfa_builder.py
=======================================
--- /branches/experimental/parser/tools/lexer_generator/nfa.py Mon Feb 10
07:59:18 2014 UTC
+++ /branches/experimental/parser/tools/lexer_generator/nfa.py Wed Feb 12
09:23:12 2014 UTC
@@ -55,9 +55,19 @@
assert isinstance(action, Action)
self.__action = action
- def transitions(self):
+ def state_iter_for_key(self, key):
+ assert self.is_closed()
+ if not key in self.__transitions:
+ return iter([])
+ return iter(self.__transitions[key])
+
+ def swap_key(self, old_key, new_key):
+ 'this is one of the few mutations allowed after closing'
assert self.is_closed()
- return self.__transitions
+ assert not new_key == TransitionKey.epsilon(), "changes epsilon
closure"
+ value = self.__transitions[old_key]
+ del self.__transitions[old_key]
+ self.__transitions[new_key] = value
def __add_transition(self, key, next_state):
assert key != None
@@ -97,6 +107,7 @@
state_filter = lambda x: True,
match_func = lambda x, y: True,
yield_func = lambda x, y: (x, y)):
+ assert self.is_closed()
for key, states in self.__transitions.items():
if key_filter(key):
for state in states:
=======================================
--- /branches/experimental/parser/tools/lexer_generator/nfa_builder.py Tue
Feb 11 18:23:07 2014 UTC
+++ /branches/experimental/parser/tools/lexer_generator/nfa_builder.py Wed
Feb 12 09:23:12 2014 UTC
@@ -248,20 +248,20 @@
@staticmethod
def __replace_catch_all(encoding, state):
catch_all = TransitionKey.unique('catch_all')
- transitions = state.transitions()
- if not catch_all in transitions:
+ states = list(state.state_iter_for_key(catch_all))
+ if not states:
return
f = lambda acc, state: acc | set(state.epsilon_closure_iter())
- reachable_states = reduce(f, transitions[catch_all], set())
- f = lambda acc, state: acc | set(state.transitions().keys())
+ reachable_states = reduce(f, states, set())
+ f = lambda acc, state: acc | set(state.key_iter())
keys = reduce(f, reachable_states, set())
keys.discard(TransitionKey.epsilon())
keys.discard(catch_all)
keys.discard(TransitionKey.unique('eos'))
inverse_key = TransitionKey.inverse_key(encoding, keys)
- if inverse_key:
- transitions[inverse_key] = transitions[catch_all]
- del transitions[catch_all]
+ if not inverse_key:
+ inverse_key = TransitionKey.unique('no_match')
+ state.swap_key(catch_all, inverse_key)
@staticmethod
def nfa(encoding, character_classes, subtree_map, name):
--
--
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