-
- // Node /////////////////////////////////////////////////////////////////////////////////
-
- /** a node in the GSS */
- final class Node extends FastSet<Node> implements Invokable<Position, Node, Node>, IntegerMappable {
-
- private Forest.Ref holder = null;
- private boolean allqueued = false;
-
- /** what state this node is in */
- public final Parser.Table<Tok>.State<Tok> state;
-
- /** which Phase this Node belongs to (node that Node is also a non-static inner class of Phase) */
- public Phase phase() { return Phase.this; }
- public Forest.Ref holder() { return holder==null ? (holder = new Forest.Ref()) : holder; }
- public Forest pending() { return Phase.this.closed ? holder().resolve() : holder; }
- public FastSet<Node> parents() { return this; }
-
- public void performReductions() {
- if (allqueued) return;
- allqueued = true;
- state.invokeReductions(token, this, this, null);
- }
-
- 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 (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);
- } 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);
- }
- }
-
- 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) {
- Forest old = holder[pos];
- holder[pos] = this.pending();
- 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;
-
- // 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.
- if (r.pos==1) rex = singularReductions.get(this.pending(), r);
- if (rex==null) {
- rex = r.rewrite(phase().getLocation());
- if (r.pos==1) singularReductions.put(this.pending(), r, rex);
- }
- if (only != null) only.finish(r, rex, target, holder);
- else for(Node child : this.parents()) child.finish(r, rex, target, holder);
- } else {
- if (only != null) only.reduce(r, pos-1, target, holder);
- else for(Node child : this.parents()) child.reduce(r, pos-1, target, holder);
- }
- 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.holder().merge(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);
- }
- public int toInt() { return idx; }
- private final int idx = node_idx++;