void DefaultErrorStrategy::sync(Parser *recognizer) {
atn::ATNState *s = recognizer->getInterpreter<atn::ATNSimulator>()->atn.states[recognizer->getState()];
// If already recovering, don't try to sync
if (inErrorRecoveryMode(recognizer)) {
return;
}
TokenStream *tokens = recognizer->getTokenStream();
size_t la = tokens->LA(1);
// try cheaper subset first; might get lucky. seems to shave a wee bit off
if (recognizer->getATN().nextTokens(s).contains(la) || la == Token::EOF) {
return;
}
// Return but don't end recovery. only do that upon valid token match
if (recognizer->isExpectedToken((int)la)) {
return;
}
switch (s->getStateType()) {
case atn::ATNState::BLOCK_START:
case atn::ATNState::STAR_BLOCK_START:
case atn::ATNState::PLUS_BLOCK_START:
case atn::ATNState::STAR_LOOP_ENTRY:
// report error and recover if possible
if (singleTokenDeletion(recognizer) != nullptr) {
return;
}
throw InputMismatchException(recognizer);
case atn::ATNState::PLUS_LOOP_BACK:
case atn::ATNState::STAR_LOOP_BACK: {
reportUnwantedToken(recognizer);
misc::IntervalSet expecting = recognizer->getExpectedTokens();
misc::IntervalSet whatFollowsLoopIterationOrRule = expecting.Or(getErrorRecoverySet(recognizer));
consumeUntil(recognizer, whatFollowsLoopIterationOrRule);
}
break;
default:
// do nothing if we can't identify the exact kind of ATN state
break;
}
}
