X-Git-Url: http://git.megacz.com/?p=sbp.git;a=blobdiff_plain;f=src%2Fedu%2Fberkeley%2Fsbp%2FForest.java;h=073e37bc84185ea26970216ed2ee2db153ecdc13;hp=4f79bb607301ff1073248f8c9275a5a20f6ddb67;hb=HEAD;hpb=2c1c0293545f3d12c23220fd05c663e6aa3f3de1

diff --git a/src/edu/berkeley/sbp/Forest.java b/src/edu/berkeley/sbp/Forest.java
index 4f79bb6..073e37b 100644
--- a/src/edu/berkeley/sbp/Forest.java
+++ b/src/edu/berkeley/sbp/Forest.java
@@ -1,10 +1,9 @@
+// Copyright 2006-2007 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>
@@ -18,24 +17,29 @@ 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) {
-        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 //////////////////////////////////////////////////////////////////////////////
 
+    public static <NodeType> Forest<NodeType> create(Input.Region region, NodeType head, Forest<NodeType>[] children) {
+        return create(region, head, children, new boolean[children==null ? 0 : children.length]); }
+    public static <NodeType> Forest<NodeType> create(Input.Region region, NodeType head, Forest<NodeType>[] children, boolean[] lifts) {
+        if (region == null) throw new RuntimeException("invoked Forest.create(region=null) -- this should never happen");
+        return new One<NodeType>(region, head, children, lifts);
+    }
+
     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);
+    abstract void edges(GraphViz.StateNode n);
     boolean ambiguous() { return false; }
-
-
+    
     // One //////////////////////////////////////////////////////////////////////////////
 
     /** A "single" forest with a head and child subforests */    
@@ -46,21 +50,25 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
         private final Forest<NodeType>[]       children;
 
         /** if true, the last child's children are considered children of this node */
-        private final boolean           lift;
+        private final boolean[]         lifts;
 
-        private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
+        public Input.Region getRegion() { return location; }
+
+        private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean[] lifts) {
             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.lifts = lifts;
         }
 
         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);
+            if (children.length == 0)
+                return new Tree<NodeType>(location, head);
+            else
+                return expand1ForOneAndMany((Forest<NodeType>)this);
         }
 
         void gather(HashSet<Forest<NodeType>> hf) {
@@ -71,9 +79,10 @@ 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, lifts));
             } else {
                 HashSet<Tree<NodeType>> ht2 = new HashSet<Tree<NodeType>>();
                 children[i].expand(ht2, ignore, bogus);
@@ -89,20 +98,20 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
 
         public boolean isTransparent() { return false; }
         public boolean isHidden() { return false; }
-        public GraphViz.Node toGraphViz(GraphViz gv) {
+        public GraphViz.StateNode toGraphViz(GraphViz gv) {
             if (gv.hasNode(this)) return gv.createNode(this);
-            GraphViz.Node n = gv.createNode(this);
+            GraphViz.StateNode n = gv.createNode(this);
             n.label = headToString()==null?"":headToString();
             n.directed = true;
             edges(n);
             return n;
         }
         boolean edges = false; // FIXME ??
-        public void edges(GraphViz.Node n) {
+        public void edges(GraphViz.StateNode n) {
             if (edges) return;
             edges = true;
             for(int i=0; i<children.length; i++) {
-                if (i==children.length-1 && lift && !children[i].ambiguous()) {
+                if (lifts[i] && !children[i].ambiguous()) {
                     children[i].edges(n);
                 } else {
                     n.edge(children[i], null);
@@ -123,13 +132,14 @@ 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() { }
 
-        public Tree<NodeType> expand1() throws Ambiguous {
+        public Input.Region getRegion() { return hp.iterator().next().getRegion(); } // all should be identical
+
+        Forest<NodeType> simplify() throws Ambiguous {
             touched();
             if (hp.size() > 1) {
                 HashSet<Forest<NodeType>> hf0 = new HashSet<Forest<NodeType>>();
@@ -145,11 +155,24 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
                 throw new Ambiguous((Forest<?>)this,
                                     (HashSet<Tree<?>>)(Object)ht);
             }
-            return hp.iterator().next().expand1();
+
+            return hp.iterator().next();
+        }
+
+        public Tree<NodeType> expand1() throws Ambiguous {
+            return simplify().expand1();
         }
         
         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);
         }
@@ -193,14 +216,14 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
 
         public boolean isTransparent() { return hp.size()==1; }
         public boolean isHidden() { return hp.size()==0; }
-        public void edges(GraphViz.Node n) {
+        public void edges(GraphViz.StateNode n) {
             if (hp.size()==1) { hp.iterator().next().edges(n); return; }
             for(Forest f : hp) f.edges(n);
         }
-        public GraphViz.Node toGraphViz(GraphViz gv) {
+        public GraphViz.StateNode toGraphViz(GraphViz gv) {
             if (hp.size()==1) return hp.iterator().next().toGraphViz(gv);
             if (gv.hasNode(this)) return gv.createNode(this);
-            GraphViz.Node n = gv.createNode(this);
+            GraphViz.StateNode n = gv.createNode(this);
             n.label = "?";
             n.color = "red";
             for(Forest f : hp) n.edge(f, null);
@@ -208,8 +231,87 @@ public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
         }
     }
 
+
     // Statics //////////////////////////////////////////////////////////////////////////////
 
+    /** Depth-first expansion, handling .One and .Many without recursion. */
+    private static <NodeType> Tree<NodeType> expand1ForOneAndMany(
+            Forest<NodeType> forest) throws Ambiguous {
+        List<Tree<NodeType>> nodes = new ArrayList<Tree<NodeType>>();
+        List<Tree<NodeType>> build = new ArrayList<Tree<NodeType>>();
+
+        // path stack
+        List<Forest.One<NodeType>> path = new ArrayList<Forest.One<NodeType>>();
+        List<Integer> sizes = new ArrayList<Integer>(),
+                      poss  = new ArrayList<Integer>();
+
+        // handle the left-most leaf
+        expand1Descend(path, nodes, sizes, poss, forest);
+
+        for (Forest.One<NodeType> f; path.size() > 0;) {
+            // up one
+            f = pop(path);
+            int size = pop(sizes) + 1;
+            int pos = pop(poss) + 1;
+            Forest<NodeType>[] children = f.children;
+            if (pos < children.length) {
+                // down the next branch
+                path.add(f);
+                sizes.add(new Integer(size));
+                poss.add(new Integer(pos));
+
+                // handle the left-most leaf
+                expand1Descend(path, nodes, sizes, poss, children[pos]);
+            } else {
+                if (path.size() > 0 && peek(path).lifts[peek(poss)]) {
+                    // skip assembling this node, lift children
+                    sizes.add(pop(sizes) + size - 1);
+                    continue;
+                }
+                // assemble this node
+                for (int i=size; i > 0; i--)
+                    build.add(nodes.remove(nodes.size() - i));
+                nodes.add(new Tree<NodeType>(f.location, f.head, build));
+                build.clear();
+            }
+        }
+
+        return pop(nodes);
+    }
+
+    /** Descend to the left-most leaf, building the path. */
+    private static <NodeType> void expand1Descend(
+            List<Forest.One<NodeType>> path, List<Tree<NodeType>> nodes,
+            List<Integer> sizes, List<Integer> poss, Forest<NodeType> f)
+            throws Ambiguous {
+        while (true) {
+            if (f instanceof Forest.Many)
+                f = ((Forest.Many<NodeType>)f).simplify();
+            else if (f instanceof Forest.One) {
+                Forest.One<NodeType> one = (Forest.One<NodeType>)f;
+                if (one.children.length == 0)
+                    break;
+                path.add(one);
+                sizes.add(0);
+                poss.add(0);
+                f = one.children[0];
+            } else {
+                nodes.add(f.expand1());
+                return;
+            }
+        }
+
+        if (path.size() > 0 && peek(path).lifts[peek(poss)])
+            sizes.add(pop(sizes) - 1); // ignore lifted leafs
+        else
+            nodes.add(f.expand1());
+    }
+
+    private static <T> T pop(List<T> list) {
+        return list.remove(list.size() - 1); }
+    private static <T> T peek(List<T> list) {
+        return list.get(list.size() - 1); }
+
     private static Tree[] tree_hint = new Tree[0];
     private static String[] string_hint = new String[0];
     private static final Forest[] emptyForestArray = new Forest[0];