X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FForest.java;h=3795c9ad19d5cdb17a2a72d9f9d1195567a82086;hp=7d872adda98152a53979ae8ac47c438dda3615fd;hb=815430f1fa820e28981bf4cff3fe15a4b9f5d97d;hpb=4b5b35b9dbcf29da663c72d12aaf6ac3d2083d27

diff --git a/src/edu/berkeley/sbp/Forest.java b/src/edu/berkeley/sbp/Forest.java
index 7d872ad..3795c9a 100644
--- a/src/edu/berkeley/sbp/Forest.java
+++ b/src/edu/berkeley/sbp/Forest.java
@@ -6,7 +6,10 @@ import java.io.*;
 import java.util.*;
 import java.lang.reflect.*;
 
-/** an efficient representation of a collection of trees (Tomita's shared packed parse forest) */
+/**
+ *   An efficient representation of a collection of trees (Tomita's
+ *   shared packed parse forest).
+ */
 public abstract class Forest<T> implements GraphViz.ToGraphViz {
 
 
@@ -16,29 +19,34 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
     /** expand this forest into a set of trees */
     public void expand(HashSet<Tree<T>> ht) { expand(ht, new HashSet<Forest<T>>(), null); }
 
-    /** create a new forest node */
+    /** create a new forest */
     public static <T> Forest<T> create(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
-        return new Body<T>(loc, head, children, unwrap);
+        return new One<T>(loc, head, children, unwrap);
     }
 
+
     // Package-Private //////////////////////////////////////////////////////////////////////////////
 
     abstract void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus);
     abstract void gather(HashSet<Forest<T>> ignore);
+    boolean ambiguous() { return false; }
 
     public abstract void edges(GraphViz.Node n);
-    public boolean ambiguous() { return false; }
 
-    // Body //////////////////////////////////////////////////////////////////////////////
 
-    private static class Body<T> extends Forest<T> /* extends PrintableTree<Forest<T>> implements */ {
+    // One //////////////////////////////////////////////////////////////////////////////
+
+    /** A "single" forest with a head and child subforests */    
+    public static class One<T> extends Forest<T> {
 
         private final Input.Region      location;
         private final T                 head;
         private final Forest<T>[]       children;
+
+        /** if true, the last child's children are considered children of this node */
         private final boolean           unwrap;
 
-        private Body(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
+        private One(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
             this.location = loc;
             this.head = head;
             this.children = children==null ? emptyForestArray : new Forest[children.length];
@@ -49,10 +57,10 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
 
         public Tree<T> expand1() throws Ambiguous {
             Tree<T>[] ret = new Tree[children.length];
-            for(int i=0; i<children.length; i++)
-                ret[i] = children[i].expand1();
+            for(int i=0; i<children.length; i++) ret[i] = children[i].expand1();
             return new Tree<T>(location, head, ret, unwrap);
         }
+
         public void gather(HashSet<Forest<T>> hf) {
             hf.add(this);
             for(Forest<T> f : children) f.gather(hf);
@@ -61,7 +69,7 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
             if (ignore.contains(this)) { ht.add(bogus); return; }
             expand(0, new Tree[children.length], ht, ignore, bogus);
         }
-        public void expand(final int i, Tree<T>[] ta, HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
+        private void expand(final int i, Tree<T>[] ta, HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
             if (i==children.length) {
                 ht.add(new Tree<T>(location, head, ta, unwrap));
             } else {
@@ -108,20 +116,24 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
     }
 
 
-    // Ref //////////////////////////////////////////////////////////////////////////////
+    // Many //////////////////////////////////////////////////////////////////////////////
+
+    /** An "ambiguity node"; this is immutable once it has been "looked at" */
+    public static class Many<T> extends Forest<T> {
 
-    /**
-     *  This class represents a partially complete collection of
-     *  forests to be viewed as a forest at some later date; once
-     *  viewed, it becomes immutable
-     */
-    static class Ref<T> extends Forest<T> {
-        public HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
+        HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
         private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
+        private boolean touched = false;
 
-        public Ref() { }
+        public Many() { }
+
+        public Iterator<One<T>> iterator() {
+            touched();
+            return (Iterator<One<T>>)hp.iterator();    // FIXME: fastset's iterator is not safe!
+        }
 
         public Tree<T> expand1() throws Ambiguous {
+            touched();
             if (hp.size() > 1) {
                 HashSet<Forest<T>> hf0 = new HashSet<Forest<T>>();
                 Iterator<Forest<T>> ih = hp.iterator();
@@ -140,30 +152,46 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
         }
         
         public void gather(HashSet<Forest<T>> ht) {
+            touched();
             ht.add(this);
             for(Forest<T> f : hp) f.gather(ht);
         }
 
-        public Forest resolve() { return this; }
-        public void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
-            if (ignore.contains(this)) { ht.add(bogus); return; }
-            for (Forest<T> f : hp) f.expand(ht, ignore, bogus);
+        private void touched() {
+            if (touched) return;
+            touched = true;
+            FastSet<Forest<T>> f2 = new FastSet<Forest<T>>();
+            for(Forest f : hp)
+                if (f instanceof Forest.One) f2.add(f);
+                else for(Forest ff : ((Forest.Many)f))
+                    f2.add(ff);
+            hp = f2;
         }
-        public boolean contains(Forest f) { return hp.contains(f); }
-        public void merge(Forest p) { if (p!=this) hp.add(p, true); }
-        public boolean ambiguous() {
+        public boolean contains(Forest f) {
+            touched();
+            return hp.contains(f);
+        }
+        public void merge(Forest p) { 
+            if (touched) throw new RuntimeException("attempt to merge() on a Forest.Many that has already been examined");
+            if (p==this) throw new RuntimeException("attempt to merge() a Forest.Many to itself!");
+            hp.add(p, true);
+        }
+        boolean ambiguous() {
+            touched();
             if (hp.size()==0) return false;
             if (hp.size()==1) return hp.iterator().next().ambiguous();
             return true;
         }
 
-        // GraphViz, ToInt //////////////////////////////////////////////////////////////////////////////
-        /*
-        public int toInt() {
-            if (hp.size()==1) return hp.iterator().next().toInt();
-            return super.toInt();
+        public void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
+            touched();
+            if (ignore.contains(this)) { ht.add(bogus); return; }
+            for (Forest<T> f : hp) f.expand(ht, ignore, bogus);
         }
-        */
+
+
+        // GraphViz, ToInt //////////////////////////////////////////////////////////////////////////////
+
         public boolean isTransparent() { return hp.size()==1; }
         public boolean isHidden() { return hp.size()==0; }
         public void edges(GraphViz.Node n) {
@@ -171,7 +199,6 @@ public abstract class Forest<T> implements GraphViz.ToGraphViz {
             for(Forest f : hp) f.edges(n);
         }
         public GraphViz.Node toGraphViz(GraphViz gv) {
-            //if (hp.size()==0) return null;
             if (hp.size()==1) return hp.iterator().next().toGraphViz(gv);
             if (gv.hasNode(this)) return gv.createNode(this);
             GraphViz.Node n = gv.createNode(this);