@Override
public void visitState(ATNState p) {
if (p.getClass() == ATNState.class && p.getNumberOfTransitions() == 1) {
ATNState q = p.transition(0).target;
if (p.transition(0) instanceof RuleTransition) {
q = ((RuleTransition) p.transition(0)).followState;
}
if (q.getClass() == ATNState.class) {
// we have p-x->q for x in {rule, action, pred, token, ...}
// if edge out of q is single epsilon to block end
// we can strip epsilon p-x->q-eps->r
Transition trans = q.transition(0);
if (q.getNumberOfTransitions() == 1
&& trans.isEpsilon()
&& !(trans instanceof ActionTransition)) {
ATNState r = trans.target;
if (r instanceof BlockEndState
|| r instanceof PlusLoopbackState
|| r instanceof StarLoopbackState) {
// skip over q
if (p.transition(0) instanceof RuleTransition) {
((RuleTransition) p.transition(0)).followState = r;
} else {
p.transition(0).target = r;
}
atn.removeState(q);
}
}
}
}
}
public void addRuleFollowLinks() {
for (ATNState p : atn.states) {
if (p != null
&& p.getClass() == ATNState.class
&& p.getNumberOfTransitions() == 1
&& p.transition(0) instanceof RuleTransition) {
RuleTransition rt = (RuleTransition) p.transition(0);
addFollowLink(rt.ruleIndex, rt.followState);
}
}
}
/**
* add an EOF transition to any rule end ATNState that points to nothing (i.e., for all those
* rules not invoked by another rule). These are start symbols then.
*
* <p>Return the number of grammar entry points; i.e., how many rules are not invoked by another
* rule (they can only be invoked from outside). These are the start rules.
*/
public int addEOFTransitionToStartRules() {
int n = 0;
ATNState eofTarget = newState(null); // one unique EOF target for all rules
for (Rule r : g.rules.values()) {
ATNState stop = atn.ruleToStopState[r.index];
if (stop.getNumberOfTransitions() > 0) continue;
n++;
Transition t = new AtomTransition(eofTarget, Token.EOF);
stop.addTransition(t);
}
return n;
}