protected SemanticContext _getPredicates(NFAState s, NFAState altStartState) {
// System.out.println("_getPredicates("+s+")");
if (s.isAcceptState()) {
return null;
}
// avoid infinite loops from (..)* etc...
if (lookBusy.contains(s)) {
return null;
}
lookBusy.add(s);
Transition transition0 = s.transition[0];
// no transitions
if (transition0 == null) {
return null;
}
// not a predicate and not even an epsilon
if (!(transition0.label.isSemanticPredicate() || transition0.label.isEpsilon())) {
return null;
}
SemanticContext p = null;
SemanticContext p0 = null;
SemanticContext p1 = null;
if (transition0.label.isSemanticPredicate()) {
// System.out.println("pred "+transition0.label);
p = transition0.label.getSemanticContext();
// ignore backtracking preds not on left edge for this decision
if (((SemanticContext.Predicate) p).predicateAST.getType() == ANTLRParser.BACKTRACK_SEMPRED
&& s == altStartState.transition[0].target) {
p = null; // don't count
}
}
// get preds from beyond this state
p0 = _getPredicates((NFAState) transition0.target, altStartState);
// get preds from other transition
Transition transition1 = s.transition[1];
if (transition1 != null) {
p1 = _getPredicates((NFAState) transition1.target, altStartState);
}
// join this&following-right|following-down
return SemanticContext.and(p, SemanticContext.or(p0, p1));
}
