- public void performReductions(Node n2) {
- if (!allqueued) performReductions();
- else state.invokeReductions(token, this, this, n2);
- }
-
- public void performEmptyReductions() { state.invokeReductions(token, this, null, null); }
- public final void invoke(Position r, Node n, Node n2) {
- //if (r.owner().lame) return;
- if (n==null || n2==null || r.pos==0) {
- if (r.pos==0) {
- if (n==null) n = this;
- else return;
- }
- if (n==null) return;
- Forest[] holder = new Forest[r.pos];
- if (r.pos==0) n.finish(r, r.zero(), n.phase(), holder);
- else n.reduce(r, r.pos-1, n.phase(), holder, null, null);
- } else {
- Forest[] holder = new Forest[r.pos];
- if (r.pos<=0) throw new Error("called wrong form of reduce()");
- int pos = r.pos-1;
- n.reduce(r, pos, n.phase(), holder, n2, null);
- }
- }
-
- /*
- public void reduce(Position r, int pos, Phase target, Forest[] holder) {
- reduce(r, pos, target, holder, null); }
- public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only) {
- reduce(r, pos, target, holder, only, this.pending());
- }
- */
- public void reduce(Position r, int pos, Phase target, Forest[] holder, Node only, Forest pending) {
- Forest old = holder[pos];
-
- // FIXME: I'm unsure about this -- basically we want to deal with the case where
- // there are two nodes, each of whose Ref points to the same Forest instance.
- // Some node in the next phase has both of these as parents. This might happen
- // since the same reduction can appear in more than one state.
-
- for(Forest result : results())
- for(Node child : ((Forest.Ref<?>)result).parents) {
- if (only != null && child!=only) continue;
- pending = holder[pos] = result;
- if (pos==0) {
- System.arraycopy(holder, 0, r.holder, 0, holder.length);
- for(int i=0; i<r.pos; i++) if (r.holder[i]==null) throw new Error("realbad");
- Forest rex = null;
- if (r.pos==1) rex = singularReductions.get(pending, r);
- if (rex==null) {
- rex = r.rewrite(phase().getLocation());
- if (r.pos==1) singularReductions.put(pending, r, rex);
- }
- child.finish(r, rex, target, holder);
- } else {
- child.reduce(r, pos-1, target, holder, null, null);
- }
- }
-
- holder[pos] = old;
- }
-
- public void finish(Position r, Forest result, Phase<Tok> target, Forest[] holder) {
- Parser.Table<Tok>.State<Tok> state0 = state.gotoSetNonTerminals.get(r.owner());
- if (result==null) throw new Error();
- if (state0!=null)
- target.newNode(this, result, state0, r.pos<=0, r);
- }
-
- private Node(Node parent, Forest pending, State state) {
- this.state = state;
- this.merge(parent, pending);
- Phase start = parent==null ? null : parent.phase();
- if (parent != null) parents().add(parent, true);
- if (Phase.this.hash.get(state, start) != null) throw new Error("severe problem!");
- Phase.this.hash.put(state, start, this);
+ /** add a new node (merging with existing nodes if possible)
+ * @param parent the parent of the new node
+ * @param result the SPPF result corresponding to the new node
+ * @param state the state that the new node is in
+ * @param fromEmptyReduction true iff this node is being created as a result of a reduction of length zero (see GRMLR paper)
+ * @param start the earliest part of the input contributing to this node (used to make merging decisions)
+ */
+ private boolean newNode(Forest f, Pos reduction, Node pred, State state, boolean fromEmptyReduction) {
+ Node p = pred==null ? null : hash.get(state, pred.phase());
+ if (p != null) {
+ p.addResult(f, reduction, pred);
+ return !state.doomed();