- /** which GSS.Phase this Node belongs to */
- public GSS.Phase phase() { return phase; }
- public Iterator<Result> iterator() { return results.iterator(); }
- public Parser.Table.State state() { return state; }
-
- public int toInt() { return idx; }
-
- 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 int idx = node_idx++;
-
- private final GSS.Phase phase;
- private final Parser.Table.State state;
- 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;
- if (r.pos==0) finish(r, r.zero(phase().getLocation().createRegion(phase().getLocation())), phase());
- else reduce(r, r.pos-1, phase(), only);
- }
-
- private void reduce(Position r, int pos, GSS.Phase target, Result only) {
- Forest[] holder = r.holder;
- Forest old = holder[pos];
- for(Result res : results)
- if (only == null || res == only) {
- Node child = res.parent();
- holder[pos] = res.getForest();
- if (pos>0) child.reduce(r, pos-1, target, null);
- else new Reduction(child, r, r.rewrite(child.phase().getLocation().createRegion(target.getLocation())), target);
- }
- holder[pos] = old;
- }
-
- void finish(Position r, Forest forest, GSS.Phase target) {
- Parser.Table.State state0 = (Parser.Table.State)state.gotoSetNonTerminals.get(r.owner());
- Result result = new Result(forest, this, r);
- target.newNodeFromReduction(result, state0, r.pos<=0, r);
- }
-
- Node(GSS.Phase phase, Result result, State state, boolean fromEmptyReduction) {
- this.phase = phase;
- 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);
-
- for(Object s : state.also)
- phase.newNode(new Result(null, this, null), (State)s, fromEmptyReduction);
-
- state.invokeReductions(phase().token, this, true, null);
- if (!fromEmptyReduction)
- state.invokeReductions(phase().getToken(), this, false, null);
- }