X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FNode.java;h=b216d3f9b664ae3f7d7848b9e44abb06631633de;hp=b360071aeadae7bdb68f6eb83ef6cd9715b6607f;hb=dc9bb3a45ed306e2e35549076842b3e74efecb48;hpb=0a543da83c6f21d79b6682415327b52abca38362

diff --git a/src/edu/berkeley/sbp/Node.java b/src/edu/berkeley/sbp/Node.java
index b360071..b216d3f 100644
--- a/src/edu/berkeley/sbp/Node.java
+++ b/src/edu/berkeley/sbp/Node.java
@@ -11,24 +11,48 @@ import java.lang.reflect.*;
 
 /** a node in the GSS */
 final class Node
-    implements Invokable<Position, Boolean, Result>,
+    implements Invokable<Position, Result>,
                IntegerMappable,
                GraphViz.ToGraphViz,
                Iterable<Result> {
 
     /** which GSS.Phase this Node belongs to */
-    public  GSS.Phase phase() { return phase; }
+    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);
-        if (fromEmptyReduction) return false;
-        state.invokeReductions(phase().getToken(), this, false, r);
-        return false;
+    boolean destroyed = false;
+
+    public void check() {
+        if (destroyed) return;
+        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; break; } }
+            else              { if (r.usedByNonDoomedNode()) { dead = false; break; } }
+        dead |= results.size()==0;
+        if (!dead || destroyed) return;
+        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);
+                break;
+            }
+        results = null;
+        children = null;
     }
 
     //////////////////////////////////////////////////////////////////////
@@ -41,46 +65,66 @@ final class Node
     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 final void invoke(Position r, Boolean emptyProductions, Result only) {
+    public final void invoke(Position r, Result only) {
+        boolean emptyProductions = only==null;
         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);
+        if (r.pos!=0)  reduce(r, r.pos-1, phase(), only);
+        else {
+            Input.Region region = phase().getLocation().createRegion(phase().getLocation());
+            new Result(r.rewrite(region, phase().parser().cache()), this, r, phase());
+        }
     }
 
     private void reduce(Position r, int pos, GSS.Phase target, Result only) {
         Forest[] holder = r.holder;
         Forest old = holder[pos];
+        if (results==null) return;   // FIXME: this should not happen
         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);
+                else {
+                    Input.Region region = child.phase().getLocation().createRegion(target.getLocation());
+                    new Reduction(child, r, r.rewrite(region, phase().parser().cache()), 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);
         if (phase.hash.get(state, result.phase()) != null) throw new Error("severe problem!");
         phase.hash.put(state, result.phase(), this);
+        addResult(result);
+        state.invokeEpsilonReductions(phase().token, this);
+    }
 
-        for(Object s : state.also)
-            phase.newNode(new Result(null, this, null), (State)s, fromEmptyReduction);
+    // Add/Remove Children/Results //////////////////////////////////////////////////////////////////////////////
 
-        state.invokeReductions(phase().token, this, true, null);
-        if (!fromEmptyReduction)
-            state.invokeReductions(phase().getToken(), this, false, null);
+    public void removeChild(Result child)   {
+        if (children==null) return;
+        children.remove(child);
+        check();
+    }
+    public void removeResult(Result result) {
+        if (results==null) return;
+        results.remove(result);
+        check();
+    }
+    public void addChild(Result child)      {
+        if (children==null) return;   // FIXME: this should not happen
+        children.add(child);
+    }
+    public void addResult(Result r) {
+        if (results.contains(r)) return;
+        results.add(r);
+        r.addChild(this);
+        if (!fromEmptyReduction) state.invokeReductions(phase().getToken(), this, r);
     }
 
     // GraphViz //////////////////////////////////////////////////////////////////////////////
@@ -89,7 +133,7 @@ final class Node
         if (results.size()==0) return null;
         if (gv.hasNode(this)) return gv.createNode(this);
         GraphViz.Node n = gv.createNode(this);
-        n.label = ""+state.toStringx();
+        n.label = "state["+state.toInt()+"]";
         n.shape = "rectangle";
         boolean hasparents = false;
         for(Result r : results) n.edge(r, "");