public boolean merge(Result r) {
if (results.contains(r)) return true;
results.add(r);
+ r.addChild(this);
if (fromEmptyReduction) return false;
state.invokeReductions(phase().getToken(), this, false, r);
return false;
}
+ private boolean destroyed = false;
+ public boolean check() {
+ boolean dead = true;
+ // - all nodes must have a parent
+ // - non-doomed nodes must either:
+ // - be on the frontier or
+ // - have a non-doomed node closer to the frontier than themself
+
+ if (phase.isFrontier()) dead = false;
+ for(Result r : children)
+ if (state.doomed) { if (r.usedByAnyNode()) dead = false; }
+ else { if (r.usedByNonDoomedNode()) dead = false; }
+ dead |= results.size()==0;
+ if (!dead || destroyed) return dead;
+ destroyed = true;
+ while(children.size()>0)
+ for(Result r : children) {
+ children.remove(r);
+ r.destroy();
+ break;
+ }
+ while(results.size()>0)
+ for(Result r : results) {
+ results.remove(r);
+ r.removeChild(this);
+ r.check();
+ break;
+ }
+ return dead;
+ }
+
//////////////////////////////////////////////////////////////////////
private static int node_idx = 0;
private final boolean fromEmptyReduction;
//private FastSet<Result> results = new FastSet<Result>();
private HashSet<Result> results = new HashSet<Result>();
+ private HashSet<Result> children = new HashSet<Result>();
+ public void removeChild(Result child) { children.remove(child); }
+ public void removeResult(Result result) { results.remove(result); }
+ public void addChild(Result child) { children.add(child); }
public final void invoke(Position r, Boolean emptyProductions, Result only) {
if (emptyProductions != (r.pos==0)) return;
this.state = state;
this.fromEmptyReduction = fromEmptyReduction;
results.add(result);
+ result.addChild(this);
if (phase.hash.get(state, result.phase()) != null) throw new Error("severe problem!");
phase.hash.put(state, result.phase(), this);