+// 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 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.MyBody<T>>*/
- implements Visitable<Forest.Body<T>>,
- IntegerMappable,
- GraphViz.ToGraphViz {
-
- private static int master_idx = 0;
- private final int idx = master_idx++;
- public int toInt() { return idx; }
+/**
+ * <font color=blue>
+ * An efficient representation of a collection of trees (Tomita's
+ * shared packed parse forest).
+ * </font>
+ */
+public abstract class Forest<NodeType> implements GraphViz.ToGraphViz {
/** 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<NodeType> expand1() throws Ambiguous;
/** expand this forest into a set of trees */
- public HashSet<Tree<T>> expand(boolean toss) {
- final HashSetTreeConsumer<T> ret = new HashSetTreeConsumer<T>();
- visit(new TreeMaker2<T>(toss, ret), null, null);
- if (toss && ret.size() > 1) throw new InnerAmbiguous(this);
- return ret;
- }
+ public void expand(HashSet<Tree<NodeType>> ht) { expand(ht, new HashSet<Forest<NodeType>>(), null); }
- private static class InnerAmbiguous extends RuntimeException {
- public final Forest<?> f;
- public InnerAmbiguous(Forest<?> f) { this.f = f; }
+ static <NodeType> Forest<NodeType> create(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
+ if (loc == null) throw new RuntimeException("invoked Forest.create(null,,,,) -- this should never happen");
+ return new One<NodeType>(loc, head, children, lift);
}
- static interface TreeConsumer<T> {
- public void addTree(Tree<T> t);
- }
- static class HashSetTreeConsumer<T> extends HashSet<Tree<T>> implements TreeConsumer<T> {
- public void addTree(Tree<T> t) {
- super.add(t);
+ /** 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); }
+
+ // Package-Private //////////////////////////////////////////////////////////////////////////////
+
+ 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 */
+ private static class One<NodeType> extends Forest<NodeType> {
+
+ private final Input.Region location;
+ private final NodeType head;
+ private final Forest<NodeType>[] children;
+
+ /** if true, the last child's children are considered children of this node */
+ private final boolean lift;
+
+ Input.Region getRegion() { return location; }
+
+ private One(Input.Region loc, NodeType head, Forest<NodeType>[] children, boolean lift) {
+ 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;
}
- }
- static <T> Forest<T> singleton(Input.Location loc, Position p) {
- return create(loc, null, new Forest[] { }, new Object[0], false, true, p); }
- static <T> Forest<T> singleton(Input.Location loc, Forest<T> body, Position p) {
- //return create(loc, null, new Forest[] { body }, false, true, p);
- return body;
- }
- static <T> Forest<T> leaf(Input.Location loc, T tag, Position p) { return create(loc, tag, null, null, false, false, p); }
- public static <T> Forest<T> create(Input.Location loc, T tag, Forest<T>[] tokens, Object[] labels, boolean unwrap, boolean singleton, Position p) {
- return new MyBody<T>(loc, tag, tokens, labels, unwrap, singleton, p);
- }
- // Body //////////////////////////////////////////////////////////////////////////////
+ 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);
+ }
- protected static interface Body<T> extends GraphViz.ToGraphViz {
- void expand(int i, TreeMaker<T> h);
- }
- public abstract void edges(GraphViz.Node n);
- public boolean ambiguous() { return false; }
- protected static class MyBody<T> extends Forest<T> implements Body<T> /* extends PrintableTree<Forest<T>> implements */ {
+ void gather(HashSet<Forest<NodeType>> hf) {
+ hf.add(this);
+ for(Forest<NodeType> f : children) f.gather(hf);
+ }
+ void expand(HashSet<Tree<NodeType>> ht, HashSet<Forest<NodeType>> ignore, Tree<NodeType> bogus) {
+ 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) {
+ if (i==children.length) {
+ ht.add(new Tree<NodeType>(location, head, ta, lift));
+ } else {
+ HashSet<Tree<NodeType>> ht2 = new HashSet<Tree<NodeType>>();
+ children[i].expand(ht2, ignore, bogus);
+ for(Tree<NodeType> 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; }
GraphViz.Node n = gv.createNode(this);
n.label = headToString()==null?"":headToString();
n.directed = true;
- n.comment = reduction==null?null:reduction+"";
edges(n);
return n;
}
- boolean edges = false;
+ boolean edges = false; // FIXME ??
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 && lift && !children[i].ambiguous()) {
+ children[i].edges(n);
} else {
- n.edge(tokens[i], labels==null?null:labels[i]);
+ n.edge(children[i], null);
}
}
}
- public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
- ivbc.invoke(this, b, c);
- }
+ protected String headToString() { return head==null?null:head.toString(); }
+ protected String headToJava() { return "null"; }
+ protected String left() { return "{"; }
+ protected String right() { return "}"; }
+ protected boolean ignoreSingleton() { return false; }
+ }
- private final Input.Location location;
- private final T tag;
- private final Forest<T>[] tokens;
- private final Object[] labels;
- private final boolean unwrap;
- private final boolean singleton;
- private final Sequence.Position reduction;
- private MyBody(Input.Location loc, T tag, Forest<T>[] tokens, Object[] labels, boolean unwrap, boolean singleton, Position reduction) {
- 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;
- this.singleton = singleton;
- this.reduction = reduction;
- this.labels = labels;
- }
-
- public void expand(final int i, final TreeMaker<T> h) {
- if (singleton) {
- tokens[0].visit(h, null, i);
- return;
- }
- if (i==0) h.start(tag, location);
+ // Many //////////////////////////////////////////////////////////////////////////////
- if (i==tokens.length) {
- h.finish(tag, location);
+ /** An "ambiguity node"; this is immutable once it has been "looked at" */
+ static class Many<NodeType> extends Forest<NodeType> {
- } else if (unwrap && i==tokens.length-1) {
- if (tokens[i] != null)
- tokens[i].visit(h, null, 0);
+ private FastSet<Forest<NodeType>> hp = new FastSet<Forest<NodeType>>();
+ private boolean touched = false;
- } else {
- tokens[i].visit(new TreeMaker<T>(h.toss) {
- public void start(T head, Input.Location loc) { }
- public void addTree(Tree<T> t, Object label) { toks.add(t); labs.add(label); }
- public void finish(T head, Input.Location loc) {
- int old = h.toks.size();
- h.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint), labs.toArray(string_hint)), labels==null?null:labels[i]);
- expand(i+1, h);
- while(h.toks.size() > old) h.toks.remove(h.toks.size()-1);
- while(h.labs.size() > old) h.labs.remove(h.labs.size()-1);
- }
- }, null, null);
- }
- }
+ public Many() { }
- protected String headToString() { return tag==null?null:tag.toString(); }
- protected String headToJava() { return null; }
- protected String left() { return "{"; }
- protected String right() { return "}"; }
- protected boolean ignoreSingleton() { return false; }
- }
+ Input.Region getRegion() { return hp.iterator().next().getRegion(); } // all should be identical
+ public Tree<NodeType> expand1() throws Ambiguous {
+ touched();
+ if (hp.size() > 1) {
+ HashSet<Forest<NodeType>> hf0 = new HashSet<Forest<NodeType>>();
+ Iterator<Forest<NodeType>> ih = hp.iterator();
+ ih.next().gather(hf0);
+ for(Forest<NodeType> f : hp) {
+ HashSet<Forest<NodeType>> hf1 = new HashSet<Forest<NodeType>>();
+ f.gather(hf1);
+ hf0.retainAll(hf1);
+ }
+ HashSet<Tree<NodeType>> ht = new HashSet<Tree<NodeType>>();
+ expand(ht, hf0, new Tree(null, "*"));
+ throw new Ambiguous((Forest<?>)this,
+ (HashSet<Tree<?>>)(Object)ht);
+ }
+ return hp.iterator().next().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;
+ }
- // Ref //////////////////////////////////////////////////////////////////////////////
+ ht.add(this);
+ for(Forest<NodeType> f : hp) f.gather(ht);
+ }
- /**
- * 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 boolean ambiguous() {
+ private void touched() {
+ if (touched) return;
+ touched = true;
+ /*
+ FastSet<Forest<NodeType>> f2 = new FastSet<Forest<NodeType>>();
+ for(Forest f : hp)
+ if (f instanceof Forest.One) f2.add(f);
+ else for(Forest ff : ((Forest.Many<NodeType>)f))
+ f2.add(ff);
+ hp = f2;
+ */
+ }
+ 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;
}
- private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
- public Ref() { }
- public int toInt() {
- if (hp.size()==1) return hp.iterator().next().toInt();
- return super.toInt();
+
+ void expand(HashSet<Tree<NodeType>> ht, HashSet<Forest<NodeType>> ignore, Tree<NodeType> bogus) {
+ touched();
+ if (ignore.contains(this)) { ht.add(bogus); return; }
+ for (Forest<NodeType> f : hp) f.expand(ht, ignore, bogus);
}
- public void merge(Forest p) { if (p!=this) hp.add(p, true); }
+
+
+ // GraphViz, ToInt //////////////////////////////////////////////////////////////////////////////
public boolean isTransparent() { return hp.size()==1; }
public boolean isHidden() { return hp.size()==0; }
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);
for(Forest f : hp) n.edge(f, null);
return n;
}
-
- public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
- if (hp==null) return;
- for(Forest<T> f : hp)
- f.visit(ivbc, b, c);
- }
- public Forest resolve() { return this; }
- }
-
- public abstract <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c);
- private static class TreeMaker2<T> extends TreeMaker<T> {
- private TreeConsumer<T> tc;
- public TreeMaker2(boolean toss, TreeConsumer<T> tc) { super(toss); this.tc = tc; }
- public void finish(T head, Input.Location loc) { tc.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint), labs.toArray(string_hint)));; }
- public void start(T head, Input.Location loc) { }
- public void addTree(Tree<T> t, Object label) { toks.add(t); labs.add(label); }
- }
- private static abstract class TreeMaker<T> implements Invokable<Forest.Body<T>,Boolean,Integer>/*, TreeConsumer<T>*/ {
- public ArrayList<Tree<T>> toks = new ArrayList<Tree<T>>();
- public ArrayList<Object> labs = new ArrayList<Object>();
- private boolean toss;
- protected T head;
- public TreeMaker(boolean toss) { this.toss = toss; }
- public abstract void start(T head, Input.Location loc);
- public abstract void finish(T head, Input.Location loc);
- public abstract void addTree(Tree<T> t, Object label);
- public void invoke(Forest.Body<T> bod, Boolean o, Integer i) {
- if (i==null) {
- ArrayList<Tree<T>> toks = this.toks;
- this.toks = new ArrayList<Tree<T>>();
- ArrayList<Object> labs = this.labs;
- this.labs = new ArrayList<Object>();
- bod.expand(0, this);
- this.toks = toks;
- this.labs = labs;
- } else {
- bod.expand(i, this);
- }
- }
}
// Statics //////////////////////////////////////////////////////////////////////////////
private static final Forest[] emptyForestArray = new Forest[0];
protected String headToString() { return null; }
- protected String headToJava() { return null; }
+ protected String headToJava() { return "null"; }
protected String left() { return "<?"; }
protected String right() { return "?>"; }
protected boolean ignoreSingleton() { return true; }