import java.util.*;
import java.lang.reflect.*;
-class Node<OtherNode extends Node>
+abstract class Node<OtherNode extends Node>
implements IntegerMappable,
GraphViz.ToGraphViz,
Iterable<OtherNode> {
+ /**
+ * Every Node has a phase; StateNodes belong to the phase in
+ * which they were shifted, ResultNodes belong to the phase of
+ * their predecessors. All of the predecessors of a given node
+ * must belong to the same phase
+ */
+ public Node(GSS.Phase phase, GSS.Phase predecessorPhase) {
+ this.phase = phase;
+ this.predecessorPhase = predecessorPhase;
+ }
+
+ private final GSS.Phase phase;
+ private final GSS.Phase predecessorPhase;
+ public GSS.Phase phase() { return phase; }
+ public GSS.Phase predecessorPhase() { return predecessorPhase; }
+ protected boolean destroyed = false;
+ private int numNonDoomedSuccessors = 0;
+ public boolean hasSuccessors() { return successors.size() > 0; }
+ public boolean hasNonDoomedSuccessors() { return numNonDoomedSuccessors > 0; }
+
+ /** only to be invoked (or overridden as public) by the subclass */
+ protected void addPred(OtherNode pred) {
+ if (predecessors.contains(pred)) throw new Error("a predecessor was added twice");
+ if (pred.phase() != predecessorPhase()) throw new Error();
+ predecessors.add(pred);
+ pred.addSucc(this);
+ }
+ public void addSucc(OtherNode succ) {
+ if (successors.contains(succ)) throw new Error("a predecessor was added twice");
+ successors.add(succ);
+ numNonDoomedSuccessors += succ.isDoomedState() ? 0 : 1;
+ if (predecessors.size() > 1 && (((Object)this) instanceof ResultNode)) throw new Error();
+ }
+ public void removeSucc(OtherNode succ) {
+ if (!successors.contains(succ)) return;
+ successors.remove(succ);
+ numNonDoomedSuccessors -= succ.isDoomedState() ? 0 : 1;
+ check();
+ }
+
+ protected void destroy() {
+ destroyed = true;
+ while(predecessors.size() > 0)
+ for(OtherNode pred : predecessors) {
+ removePred(pred);
+ pred.removeSucc(this);
+ break;
+ }
+ predecessors = null;
+ while(successors.size() > 0)
+ for(OtherNode succ : successors) {
+ removeSucc(succ);
+ succ.removePred(this);
+ break;
+ }
+ successors = null;
+ }
+
+ public abstract boolean isDoomedState();
+ protected abstract void check();
+
+ public void removePred(OtherNode pred) {
+ if (!predecessors.contains(pred)) return;
+ predecessors.remove(pred);
+ check();
+ }
+
protected FastSet<OtherNode> predecessors = new FastSet<OtherNode>();
protected FastSet<OtherNode> successors = new FastSet<OtherNode>();
//private HashSet<OtherNode> predecessors = new HashSet<OtherNode>();
extends Node<StateNode> {
private Forest.Many f = new Forest.Many();
- private boolean destroyed = false;
- private boolean primordeal;
- private int usedByNonDoomedNode = 0;
private Pos reduction;
- private GSS.Phase predPhase;
+ public void merge(Forest newf) { this.f.merge(newf); }
public Pos reduction() { return reduction; }
- public void merge(Forest newf) {
- this.f.merge(newf);
- /*
- if (predecessors.contains(pred)) return;
- addPred(pred);
- if (fromEmptyReduction) return;
- n.state().invokeReductions(n.phase().getToken(), n, this);
- */
- }
-
- public GSS.Phase phase() { return predPhase; }
+ public boolean isDoomedState() { /* this is irrelevant */ return false; }
public Forest getForest() { return f; }
- public void addSucc(StateNode succ) {
- if (successors.contains(succ)) return;
- successors.add(succ);
- usedByNonDoomedNode += succ.state().doomed ? 0 : 1;
- if (predecessors.size() > 1) throw new Error();
- }
- public void removeSucc(StateNode succ) {
- if (!successors.contains(succ)) return;
- successors.remove(succ);
- usedByNonDoomedNode -= succ.state().doomed ? 0 : 1;
- check();
- }
-
- public boolean usedByAnyNode() { return successors.size() > 0; }
- public boolean usedByNonDoomedNode() { return usedByNonDoomedNode > 0; }
-
- public String toString() { return super.toString()+"->"+predPhase; }
+ public String toString() { return super.toString()+"->"+phase(); }
public void check() {
+ if (destroyed) return;
if (successors.size()==0) destroy();
else if (predecessors.size()==0) destroy();
}
- public void destroy() {
+ protected void destroy() {
if (destroyed) return;
- if (primordeal) return; // never destroy the "primordeal" result
- destroyed = true;
- while(predecessors.size() > 0)
- for(StateNode pred : predecessors) {
- removePred(pred);
- pred.removeSucc(this);
- break;
- }
- predecessors = null;
- while(successors.size() > 0)
- for(StateNode succ : successors) {
- removeSucc(succ);
- succ.removePred(this);
- break;
- }
- successors = null;
- }
-
- public void removePred(StateNode pred) {
- if (!predecessors.contains(pred)) return;
- predecessors.remove(pred);
- check();
+ if (predecessorPhase()==null) return; // never destroy the "primordeal" result
+ super.destroy();
}
public void addPred(StateNode pred) {
- if (predPhase==null) predPhase = pred.phase();
- if (predPhase != pred.phase()) throw new Error();
- predecessors.add(pred);
- pred.addSucc(this);
+ super.addPred(pred);
+ // results have only one predecessor
if (predecessors.size() > 1) throw new Error();
}
- public ResultNode() {
- this(null, null, null);
- this.primordeal = true;
- }
+ public ResultNode() { this(null, null, null); }
public ResultNode(Forest f, Pos reduction, StateNode pred) {
+ super(pred==null ? null : pred.phase(),
+ pred==null ? null : pred.phase());
this.f.merge(f);
this.reduction = reduction;
if (pred != null) addPred(pred);
}
-
-
}
\ No newline at end of file
extends Node<ResultNode>
implements Invokable<Pos, ResultNode, Object> {
+ private final Parser.Table.State state;
+ private boolean fromEmptyReduction;
+
/** which GSS.Phase this StateNode belongs to */
- public GSS.Phase phase() { return phase; }
public Iterator<ResultNode> iterator() { return predecessors.iterator(); }
public Parser.Table.State state() { return state; }
-
- boolean destroyed = false;
+ public boolean isDoomedState() { return state.doomed; }
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;
+ 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; } }
+ if (state.doomed) { if (r.hasSuccessors()) { dead = false; break; } }
+ else { if (r.hasNonDoomedSuccessors()) { dead = false; break; } }
dead |= predecessors.size()==0;
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(predecessors.size()>0)
- for(ResultNode r : predecessors) {
- predecessors.remove(r);
- r.removeSucc(this);
- break;
- }
- predecessors = 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;
-
public final void invoke(Pos r, ResultNode only, Object o) {
boolean emptyProductions = only==null;
if (emptyProductions != (r.numPops()==0)) return;
this(phase, new ResultNode(f, reduction, pred), state, fromEmptyReduction);
}
StateNode(GSS.Phase phase, ResultNode pred, State state, boolean fromEmptyReduction) {
- this.phase = phase;
+ 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);
-
- predecessors.add(pred);
- pred.addSucc(this);
- if (!fromEmptyReduction)
- state.invokeReductions(phase().getToken(), this, pred);
-
+ addPred(pred);
state.invokeEpsilonReductions(phase().token, this);
}
// Add/Remove Successors/Predecessors //////////////////////////////////////////////////////////////////////////////
- public void removeSucc(ResultNode succ) {
- successors.remove(succ);
- check();
- }
- public void removePred(ResultNode result) {
- predecessors.remove(result);
- check();
- }
- public void addSucc(ResultNode succ) {
- successors.add(succ);
- }
public void addPred(Forest f, Pos reduction, StateNode pred) {
for(ResultNode r : predecessors)
if (r.predecessorsContains(pred)) {
r.merge(f);
return;
}
- ResultNode result = new ResultNode(f, reduction, pred);
- predecessors.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);
+ if (!this.fromEmptyReduction)
+ state.invokeReductions(phase().getToken(), this, result);
}
}
projects / sbp.git / commitdiff