/** a node in the GSS */
final class StateNode
- extends Node
- implements Invokable<Pos, ResultNode, Object>,
- Iterable<ResultNode> {
+ extends Node<ResultNode>
+ implements Invokable<Pos, ResultNode, Object> {
+
+ private final Parser.Table.State state;
/** which GSS.Phase this StateNode belongs to */
- public GSS.Phase phase() { return phase; }
- public Iterator<ResultNode> iterator() { return results.iterator(); }
public Parser.Table.State state() { return state; }
-
- boolean destroyed = false;
+ public boolean isDoomedState() { return state.doomed; }
+ public boolean hasPathToRoot() {
+ if (state.doomed) return false;
+ return super.hasPathToRoot();
+ }
public void check() {
if (destroyed) return;
// - 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;
- else for(ResultNode r : successors)
- if (state.doomed) { if (r.usedByAnyNode()) { dead = false; break; } }
- else { if (r.usedByNonDoomedNode()) { dead = false; break; } }
- dead |= results.size()==0;
+ if (phase().isFrontier()) dead = false;
+ else for(ResultNode r : successors())
+ if (state.doomed) { if (r.hasSuccessors()) { dead = false; break; } }
+ else { if (r.hasNonDoomedSuccessors()) { dead = false; break; } }
+ dead |= !hasPredecessors();
if (!dead) return;
- destroyed = true;
if (phase() != null && phase().hash != null)
- phase().hash.remove(state, predPhase);
- while(successors.size()>0)
- for(ResultNode r : successors) {
- successors.remove(r);
- r.removePred(this);
- break;
- }
- while(results.size()>0)
- for(ResultNode r : results) {
- results.remove(r);
- r.removeSucc(this);
- break;
- }
- results = null;
- successors = null;
+ phase().hash.remove(state, predecessorPhase());
+ destroy();
}
- //////////////////////////////////////////////////////////////////////
-
- private final GSS.Phase phase;
- private final GSS.Phase predPhase;
- private final Parser.Table.State state;
- private boolean fromEmptyReduction;
- private FastSet<ResultNode> results = new FastSet<ResultNode>();
- private FastSet<ResultNode> successors = new FastSet<ResultNode>();
- //private HashSet<ResultNode> results = new HashSet<ResultNode>();
- //private HashSet<ResultNode> successors = new HashSet<ResultNode>();
-
public final void invoke(Pos r, ResultNode only, Object o) {
boolean emptyProductions = only==null;
if (emptyProductions != (r.numPops()==0)) return;
- if (r.numPops()!=0) reduce(r, r.numPops()-1, phase(), only);
- else {
+ if (r.numPops()==0) {
Input.Region region = phase().getLocation().createRegion(phase().getLocation());
phase().newNodeFromReduction(r.rewrite(region), r, this);
+ } else {
+ // never start reductions at a node that was created via a right-nulled rule
+ if (only.reduction() != null && only.reduction().numPops()==0) return;
+ reduce(r, r.numPops()-1, phase(), only);
}
}
private void reduce(Pos r, int pos, GSS.Phase target, ResultNode only) {
- for(ResultNode res : results)
+ for(ResultNode res : this)
if (only == null || res == only)
- for(StateNode pred : res.getPreds())
- reduce2(r, pos, target, pred, res.getForest());
+ for(StateNode pred : res) {
+ Forest[] holder = r.holder;
+ Forest old = pos >= holder.length ? null : holder[pos];
+ if (pos < holder.length) holder[pos] = res.getForest();
+ if (pos>0) pred.reduce(r, pos-1, target, null);
+ else new Reduction(pred, r,
+ pred.hasPathToRoot()
+ ? r.rewrite(pred.phase().getLocation().createRegion(target.getLocation()))
+ : null,
+ target);
+ if (pos < holder.length) holder[pos] = old;
+ }
}
- void reduce2(Pos r, int pos, GSS.Phase target, StateNode pred, Forest f) {
- Forest[] holder = r.holder;
- Forest old = pos >= holder.length ? null : holder[pos];
- if (pos < holder.length) holder[pos] = f;
- if (pos>0) pred.reduce(r, pos-1, target, null);
- else {
- Input.Region region = pred.phase().getLocation().createRegion(target.getLocation());
- new Reduction(pred, r, r.rewrite(region), target);
- }
- if (pos < holder.length) holder[pos] = old;
- }
-
- StateNode(GSS.Phase phase, Forest f, Pos reduction, StateNode pred, State state, boolean fromEmptyReduction) {
- this(phase, new ResultNode(f, reduction, pred), state, fromEmptyReduction);
- }
- StateNode(GSS.Phase phase, ResultNode pred, State state, boolean fromEmptyReduction) {
- this.phase = phase;
+ StateNode(GSS.Phase phase, ResultNode pred, State state) {
+ super(phase, pred.phase());
this.state = state;
- this.fromEmptyReduction = fromEmptyReduction;
if (phase.hash.get(state, pred.phase()) != null) throw new Error("severe problem!");
- this.predPhase = pred.phase();
phase.hash.put(state, pred.phase(), this);
-
- results.add(pred);
- pred.addSucc(this);
- if (!fromEmptyReduction)
- state.invokeReductions(phase().getToken(), this, pred);
-
+ addPred(pred);
state.invokeEpsilonReductions(phase().token, this);
}
- // Add/Remove Successors/Results //////////////////////////////////////////////////////////////////////////////
+ // Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
- public void removeSucc(ResultNode succ) {
- successors.remove(succ);
- check();
- }
- public void removeResult(ResultNode result) {
- results.remove(result);
- check();
- }
- public void addSucc(ResultNode succ) {
- successors.add(succ);
- }
- public void addResult(Forest f, Pos reduction, StateNode pred) {
- for(ResultNode r : results)
+ public void addPred(Forest f, Pos reduction, StateNode pred) {
+ for(ResultNode r : this)
if (r.predecessorsContains(pred)) {
r.merge(f);
return;
}
- ResultNode result = new ResultNode(f, reduction, pred);
- results.add(result);
- result.addSucc(this);
- if (!this.fromEmptyReduction) state.invokeReductions(phase().getToken(), this, result);
+ addPred(new ResultNode(f, reduction, pred));
+ }
+ protected void addPred(ResultNode result) {
+ super.addPred(result);
+ state.invokeReductions(phase().getToken(), this, result);
}
}
projects / sbp.git / blobdiff