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Restrict lexer action execution to actions defined in the root lexer rule that matches a token

This commit is contained in:
Sam Harwell 2014-01-18 16:06:12 -06:00
parent 9b85e9c636
commit 214b715107
1 changed files with 22 additions and 3 deletions
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19
runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java
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@ -524,9 +524,28 @@ public class LexerATNSimulator extends ATNSimulator {
break;
case Transition.ACTION:
if (config.context == null || config.context.hasEmptyPath()) {
// execute actions anywhere in the start rule for a token.
//
// TODO: if the entry rule is invoked recursively, some
// actions may be executed during the recursive call. The
// problem can appear when hasEmptyPath() is true but
// isEmpty() is false. In this case, the config needs to be
// split into two contexts - one with just the empty path
// and another with everything but the empty path.
// Unfortunately, the current algorithm does not allow
// getEpsilonTarget to return two configurations, so
// additional modifications are needed before we can support
// the split operation.
LexerActionExecutor lexerActionExecutor = LexerActionExecutor.append(config.lexerActionExecutor, atn.lexerActions[((ActionTransition)t).actionIndex]);
c = new LexerATNConfig(config, t.target, lexerActionExecutor);
break;
}
else {
// ignore actions in referenced rules
c = new LexerATNConfig(config, t.target);
break;
}
case Transition.EPSILON:
c = new LexerATNConfig(config, t.target);