X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FForest.java;h=34982bd11d935d2e238e059e29c1eb305af18ae4;hp=43ffb10fcfc4a0a1daaef9f0c59e92dc8559dfc1;hb=2afdfe14e78fa0597186614937c679a09d74ecdf;hpb=8a5250c184672495fae152e096b2e800749cd0db

diff --git a/src/edu/berkeley/sbp/Forest.java b/src/edu/berkeley/sbp/Forest.java
index 43ffb10..34982bd 100644
--- a/src/edu/berkeley/sbp/Forest.java
+++ b/src/edu/berkeley/sbp/Forest.java
@@ -1,10 +1,9 @@
+// Copyright 2006 all rights reserved; see LICENSE file for BSD-style license
+
 package edu.berkeley.sbp;
-import edu.berkeley.sbp.*;
-import edu.berkeley.sbp.Sequence.Position;
 import edu.berkeley.sbp.util.*;
 import java.io.*;
 import java.util.*;
-import java.lang.reflect.*;
 
 /**
  *   <font color=blue>
@@ -18,26 +17,38 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
     public abstract Tree<NodeType> expand1() throws Ambiguous;
 
     /** expand this forest into a set of trees */
-    public void expand(HashSet<Tree<NodeType>> ht) { expand(ht, new HashSet<Forest<NodeType>>(), null); }
-
-    static <NodeType> Forest<NodeType> create(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
-        if (loc == null) throw new Error();
-        return new One<NodeType>(loc, head, children, lift);
+    public Iterable<Tree<NodeType>> expand() {
+        HashSet<Tree<NodeType>> ht = new HashSet<Tree<NodeType>>();
+        expand(ht, new HashSet<Forest<NodeType>>(), null);
+        return ht;
     }
 
-    /** create a new forest */
-    public static <NodeType> Forest<NodeType> create(Input.Region loc, NodeType head, Forest<NodeType>[] children) {
-        return Forest.create(loc, head, children, false); }
+    /** returns the input Region which this Forest was parsed from */
+    public abstract Input.Region getRegion();
 
     // Package-Private //////////////////////////////////////////////////////////////////////////////
 
+    static <NodeType> Forest<NodeType> create(Input.Region region, NodeType head, Forest<NodeType>[] children,
+                                              boolean lift) {
+        if (region == null) throw new RuntimeException("invoked Forest.create(region=null) -- this should never happen");
+        return new One<NodeType>(region, head, children, lift);
+    }
+
+    static <NodeType> Forest<NodeType> create(Input.Region region, NodeType head, Forest<NodeType>[] children,
+                                              boolean lift, boolean liftLeft) {
+        if (region == null) throw new RuntimeException("invoked Forest.create(region=null) -- this should never happen");
+        return new One<NodeType>(region, head, children, lift, liftLeft);
+    }
+
+    /** create a new forest */
+    public static <NodeType> Forest<NodeType> create(Input.Region region, NodeType head, Forest<NodeType>[] children) {
+        return Forest.create(region, head, children, false); }
+
     abstract void expand(HashSet<Tree<NodeType>> ht, HashSet<Forest<NodeType>> ignore, Tree<NodeType> bogus);
     abstract void gather(HashSet<Forest<NodeType>> ignore);
     abstract void edges(GraphViz.Node n);
     boolean ambiguous() { return false; }
     
-    abstract Input.Region getRegion();
-
     // One //////////////////////////////////////////////////////////////////////////////
 
     /** A "single" forest with a head and child subforests */    
@@ -49,22 +60,28 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
 
         /** if true, the last child's children are considered children of this node */
         private final boolean           lift;
+        private final boolean           liftLeft;
 
-        Input.Region getRegion() { return location; }
+        public Input.Region getRegion() { return location; }
 
         private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
+            this(loc, head, children, lift, false);
+        }
+        private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift, boolean liftLeft) {
             this.location = loc;
             this.head = head;
+            if (head==null) throw new RuntimeException("invoked Forest.create(,null,,,) -- this should never happen");
             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.lift = lift;
+            this.liftLeft = liftLeft;
         }
 
         public Tree<NodeType> expand1() throws Ambiguous {
             Tree<NodeType>[] ret = new Tree[children.length];
             for(int i=0; i<children.length; i++) ret[i] = children[i].expand1();
-            return new Tree<NodeType>(location, head, ret, lift);
+            return new Tree<NodeType>(location, head, ret, lift, liftLeft);
         }
 
         void gather(HashSet<Forest<NodeType>> hf) {
@@ -75,9 +92,10 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
             if (ignore.contains(this)) { ht.add(bogus); return; }
             expand(0, new Tree[children.length], ht, ignore, bogus);
         }
-        private void expand(final int i, Tree<NodeType>[] ta, HashSet<Tree<NodeType>> ht, HashSet<Forest<NodeType>> ignore, Tree<NodeType> bogus) {
+        private void expand(final int i, Tree<NodeType>[] ta, HashSet<Tree<NodeType>> ht, HashSet<Forest<NodeType>> ignore,
+                            Tree<NodeType> bogus) {
             if (i==children.length) {
-                ht.add(new Tree<NodeType>(location, head, ta, lift));
+                ht.add(new Tree<NodeType>(location, head, ta, lift, liftLeft));
             } else {
                 HashSet<Tree<NodeType>> ht2 = new HashSet<Tree<NodeType>>();
                 children[i].expand(ht2, ignore, bogus);
@@ -127,13 +145,12 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
     /** An "ambiguity node"; this is immutable once it has been "looked at" */
     static class Many<NodeType> extends Forest<NodeType> {
 
-        HashSet<GSS.Phase.Node> parents = new HashSet<GSS.Phase.Node>();
         private FastSet<Forest<NodeType>> hp = new FastSet<Forest<NodeType>>();
         private boolean touched = false;
 
         public Many() { }
 
-        Input.Region getRegion() { return hp.iterator().next().getRegion(); } // all should be identical
+        public Input.Region getRegion() { return hp.iterator().next().getRegion(); } // all should be identical
 
         public Tree<NodeType> expand1() throws Ambiguous {
             touched();
@@ -156,6 +173,14 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
         
         void gather(HashSet<Forest<NodeType>> ht) {
             touched();
+
+            // FIXME: do something more sensible here
+            if (ht.contains(this)) {
+                System.err.println("WARNING: grammar produced a circular forest\n" + this);
+                //throw new Error("grammar produced a circular forest:\n" + this);
+                return;
+            }
+
             ht.add(this);
             for(Forest<NodeType> f : hp) f.gather(ht);
         }