Revision: 17581
Author: [email protected]
Date: Fri Nov 8 10:28:35 2013 UTC
Log: Experimental lexer generator: fix dfa generation when there are
epsilon transitions with actions.
[email protected]
BUG=
Review URL: https://codereview.chromium.org/66493003
http://code.google.com/p/v8/source/detail?r=17581
Modified:
/branches/experimental/parser/tools/lexer_generator/lexer_test.py
/branches/experimental/parser/tools/lexer_generator/nfa.py
=======================================
--- /branches/experimental/parser/tools/lexer_generator/lexer_test.py Thu
Nov 7 15:42:57 2013 UTC
+++ /branches/experimental/parser/tools/lexer_generator/lexer_test.py Fri
Nov 8 10:28:35 2013 UTC
@@ -65,3 +65,22 @@
self.__verify_action_stream(
lexer.lex(string),
[('SHL', '<<'), ('SPACE', ' '), ('LT', '<')])
+
+
+ def test_consecutive_epsilon_transitions(self):
+ # This rule set will create a NFA where we first have an epsilon
transition,
+ # then following that, an epsilon transition with an action. This will
test
+ # that the action is correctly pulled forward when creating the dfa.
+ rules = '''
+ digit = [0-9];
+ number = (digit+ ("." digit+)?);
+ <default>
+ number { NUMBER }
+ eof <<terminate>>'''
+
+ lexer = Lexer(rules)
+
+ string = '555\0'
+ self.__verify_action_stream(
+ lexer.lex(string),
+ [('NUMBER', '555')])
=======================================
--- /branches/experimental/parser/tools/lexer_generator/nfa.py Fri Nov 8
07:29:01 2013 UTC
+++ /branches/experimental/parser/tools/lexer_generator/nfa.py Fri Nov 8
10:28:35 2013 UTC
@@ -399,6 +399,11 @@
for e_trans in state.transitions()[e]:
if e_trans[1]:
actions.append(e_trans[1])
+ for s in state.epsilon_closure():
+ if e in s.transitions():
+ for e_trans in s.transitions()[e]:
+ if e_trans[1]:
+ actions.append(e_trans[1])
assert len(match_states) == len(transitions)
--
--
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