checkpoint
[sbp.git] / src / edu / berkeley / sbp / Forest.java
index 00f826a..7d872ad 100644 (file)
@@ -7,51 +7,76 @@ import java.util.*;
 import java.lang.reflect.*;
 
 /** an efficient representation of a collection of trees (Tomita's shared packed parse forest) */
-public abstract class Forest<T> /*extends PrintableTree<Forest.Body<T>>*/
-    implements IntegerMappable,
-               GraphViz.ToGraphViz {
+public abstract class Forest<T> implements GraphViz.ToGraphViz {
 
-    private static int master_idx = 0;
-    private final int idx = master_idx++;
-    public int toInt() { return idx; }
 
     /** assume that this forest contains exactly one tree and return it; otherwise throw an exception */
-    public final Tree<T> expand1() throws Ambiguous, ParseFailed {
-        try {
-            Iterator<Tree<T>> it = expand(true).iterator();
-            if (!it.hasNext()) throw new ParseFailed();
-            return it.next();
-        } catch (InnerAmbiguous ia) { throw new Ambiguous(ia.f); }
-    }
+    public abstract Tree<T> expand1() throws Ambiguous;
 
     /** expand this forest into a set of trees */
-    public abstract void expand(HashSet<Tree<T>> ht);
-    public HashSet<Tree<T>> expand(boolean toss) {
-        HashSet<Tree<T>> ret = new HashSet<Tree<T>>();
-        expand(ret);
-        return ret;
-    }
+    public void expand(HashSet<Tree<T>> ht) { expand(ht, new HashSet<Forest<T>>(), null); }
 
-    private static class InnerAmbiguous extends RuntimeException {
-        public final Forest<?> f;
-        public InnerAmbiguous(Forest<?> f) { this.f = f; }
+    /** create a new forest node */
+    public static <T> Forest<T> create(Input.Region loc, T head, Forest<T>[] children, boolean unwrap) {
+        return new Body<T>(loc, head, children, unwrap);
     }
 
-    static        <T> Forest<T> leaf(Input.Region loc, T tag) { return create(loc, tag, null, false); }
-    public static <T> Forest<T> create(Input.Region loc, T tag, Forest<T>[] tokens, boolean unwrap) {
-        return new Body<T>(loc, tag, tokens, unwrap);
-    }
-    // Body //////////////////////////////////////////////////////////////////////////////
+    // Package-Private //////////////////////////////////////////////////////////////////////////////
+
+    abstract void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus);
+    abstract void gather(HashSet<Forest<T>> ignore);
 
     public abstract void edges(GraphViz.Node n);
     public boolean ambiguous() { return false; }
-    public /*protected*/ static class Body<T> extends Forest<T> /* extends PrintableTree<Forest<T>> implements */ {
+
+    // Body //////////////////////////////////////////////////////////////////////////////
+
+    private static class Body<T> extends Forest<T> /* extends PrintableTree<Forest<T>> implements */ {
 
         private final Input.Region      location;
-        private final T                 tag;
-        private final Forest<T>[]       tokens;
+        private final T                 head;
+        private final Forest<T>[]       children;
         private final boolean           unwrap;
 
+        private Body(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];
+            if (children != null) System.arraycopy(children, 0, this.children, 0, children.length);
+            if (children != null) for(int i=0; i<children.length; i++) if (children[i]==null) throw new Error(i+"");
+            this.unwrap = unwrap;
+        }
+
+        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();
+            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);
+        }
+        public void expand(HashSet<Tree<T>> ht, HashSet<Forest<T>> ignore, Tree<T> bogus) {
+            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) {
+            if (i==children.length) {
+                ht.add(new Tree<T>(location, head, ta, unwrap));
+            } else {
+                HashSet<Tree<T>> ht2 = new HashSet<Tree<T>>();
+                children[i].expand(ht2, ignore, bogus);
+                for(Tree<T> tc : ht2) {
+                    ta[i] = tc;
+                    expand(i+1, ta, ht, ignore, bogus);
+                    ta[i] = null;
+                }
+            }
+        }
+
+        // GraphViz, ToInt //////////////////////////////////////////////////////////////////////////////
+
         public boolean isTransparent() { return false; }
         public boolean isHidden() { return false; }
         public GraphViz.Node toGraphViz(GraphViz gv) {
@@ -59,7 +84,6 @@ public abstract class Forest<T> /*extends PrintableTree<Forest.Body<T>>*/
             GraphViz.Node n = gv.createNode(this);
             n.label = headToString()==null?"":headToString();
             n.directed = true;
-            //n.comment = reduction==null?null:reduction+"";
             edges(n);
             return n;
         }
@@ -67,42 +91,16 @@ public abstract class Forest<T> /*extends PrintableTree<Forest.Body<T>>*/
         public void edges(GraphViz.Node n) {
             if (edges) return;
             edges = true;
-            for(int i=0; i<tokens.length; i++) {
-                if (i==tokens.length-1 && unwrap && !tokens[i].ambiguous()) {
-                    tokens[i].edges(n);
+            for(int i=0; i<children.length; i++) {
+                if (i==children.length-1 && unwrap && !children[i].ambiguous()) {
+                    children[i].edges(n);
                 } else {
-                    n.edge(tokens[i], null);
+                    n.edge(children[i], null);
                 }
             }
         }
 
-        private Body(Input.Region loc, T tag, Forest<T>[] tokens, boolean unwrap) {
-            this.location = loc;
-            this.tag = tag;
-            this.tokens = tokens==null ? emptyForestArray : new Forest[tokens.length];
-            if (tokens != null) System.arraycopy(tokens, 0, this.tokens, 0, tokens.length);
-            if (tokens != null) for(int i=0; i<tokens.length; i++) if (tokens[i]==null) throw new Error(i+"");
-            this.unwrap = unwrap;
-        }
-
-        public void expand(HashSet<Tree<T>> ht) {
-            expand(0, new Tree[tokens.length], ht);
-        }
-        public void expand(final int i, Tree<T>[] ta, HashSet<Tree<T>> ht) {
-            if (i==tokens.length) {
-                ht.add(new Tree<T>(location, tag, ta, unwrap));
-                return;
-            }
-            HashSet<Tree<T>> ht2 = new HashSet<Tree<T>>();
-            tokens[i].expand(ht2);
-            for(Tree<T> tc : ht2) {
-                ta[i] = tc;
-                expand(i+1, ta, ht);
-                ta[i] = null;
-            }
-        }
-
-        protected String  headToString()         { return tag==null?null:tag.toString(); }
+        protected String  headToString()         { return head==null?null:head.toString(); }
         protected String  headToJava()           { return "null"; }
         protected String  left()                 { return "{"; }
         protected String  right()                { return "}"; }
@@ -118,27 +116,54 @@ public abstract class Forest<T> /*extends PrintableTree<Forest.Body<T>>*/
      *  viewed, it becomes immutable
      */
     static class Ref<T> extends Forest<T> {
-        public void expand(HashSet<Tree<T>> ht) {
-            for (Forest<T> f : hp)
-                f.expand(ht);
-        }
         public HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
-        public boolean contains(Forest f) {
-            return hp.contains(f);
+        private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
+
+        public Ref() { }
+
+        public Tree<T> expand1() throws Ambiguous {
+            if (hp.size() > 1) {
+                HashSet<Forest<T>> hf0 = new HashSet<Forest<T>>();
+                Iterator<Forest<T>> ih = hp.iterator();
+                ih.next().gather(hf0);
+                for(Forest<T> f : hp) {
+                    HashSet<Forest<T>> hf1 = new HashSet<Forest<T>>();
+                    f.gather(hf1);
+                    hf0.retainAll(hf1);
+                }
+                HashSet<Tree<T>> ht = new HashSet<Tree<T>>();
+                expand(ht, hf0, new Tree(null, "*"));
+                throw new Ambiguous((Forest<?>)this,
+                                    (HashSet<Tree<?>>)(Object)ht);
+            }
+            return hp.iterator().next().expand1();
         }
+        
+        public void gather(HashSet<Forest<T>> ht) {
+            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);
+        }
+        public boolean contains(Forest f) { return hp.contains(f); }
+        public void merge(Forest p) { if (p!=this) hp.add(p, true); }
         public boolean ambiguous() {
             if (hp.size()==0) return false;
             if (hp.size()==1) return hp.iterator().next().ambiguous();
             return true;
         }
-        private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
-        public Ref() { }
+
+        // GraphViz, ToInt //////////////////////////////////////////////////////////////////////////////
+        /*
         public int toInt() {
             if (hp.size()==1) return hp.iterator().next().toInt();
             return super.toInt();
         }
-        public void merge(Forest p) { if (p!=this) hp.add(p, true); }
-
+        */
         public boolean isTransparent() { return hp.size()==1; }
         public boolean isHidden() { return hp.size()==0; }
         public void edges(GraphViz.Node n) {
@@ -155,8 +180,6 @@ public abstract class Forest<T> /*extends PrintableTree<Forest.Body<T>>*/
             for(Forest f : hp) n.edge(f, null);
             return n;
         }
-
-        public Forest resolve() { return this; }
     }
 
     // Statics //////////////////////////////////////////////////////////////////////////////