1 package edu.berkeley.sbp;
2 import edu.berkeley.sbp.*;
3 import edu.berkeley.sbp.Sequence.Position;
4 import edu.berkeley.sbp.util.*;
7 import java.lang.reflect.*;
9 /** an efficient representation of a collection of trees (Tomita's shared packed parse forest) */
10 public abstract class Forest<T> /*extends PrintableTree<Forest.MyBody<T>>*/ implements Visitable<Forest.Body<T>> {
12 /** assume that this forest contains exactly one tree and return it; otherwise throw an exception */
13 public final Tree<T> expand1() throws Ambiguous, ParseFailed {
15 Iterator<Tree<T>> it = expand(true).iterator();
16 if (!it.hasNext()) throw new ParseFailed();
18 } catch (InnerAmbiguous ia) { throw new Ambiguous(ia.f); }
21 /** expand this forest into a set of trees */
22 public HashSet<Tree<T>> expand(boolean toss) {
24 final HashSetTreeConsumer<T> ret = new HashSetTreeConsumer<T>();
25 visit(new TreeMaker2<T>(toss, ret), null, null);
26 if (toss && ret.size() > 1) throw new InnerAmbiguous(this);
30 private static class InnerAmbiguous extends RuntimeException {
31 public final Forest<?> f;
32 public InnerAmbiguous(Forest<?> f) { this.f = f; }
35 public static interface TreeConsumer<T> {
36 public void addTree(Tree<T> t);
38 public static class HashSetTreeConsumer<T> extends HashSet<Tree<T>> implements TreeConsumer<T> {
39 public void addTree(Tree<T> t) { super.add(t); }
42 static <T> Forest<T> singleton(Input.Location loc, Position p) {
43 return create(loc, null, new Forest[] { }, false, true, p); }
44 static <T> Forest<T> singleton(Input.Location loc, Forest<T> body, Position p) {
45 return create(loc, null, new Forest[] { body }, false, true, p); }
46 static <T> Forest<T> leaf(Input.Location loc, T tag, Position p) { return create(loc, tag, null, false, false, p); }
48 public static <T> Forest<T> create(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton, Position p) {
49 return new MyBody<T>(loc, tag, tokens, unwrap, singleton, p);
52 // Body //////////////////////////////////////////////////////////////////////////////
54 protected static interface Body<T> {
55 void expand(int i, TreeMaker<T> h);
58 protected static class MyBody<T> extends Forest<T> implements Body<T> /* extends PrintableTree<Forest<T>> implements */ {
60 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
61 ivbc.invoke(this, b, c);
64 private final Input.Location location;
66 private final Forest<T>[] tokens;
67 private final boolean unwrap;
68 private final boolean singleton;
69 private final Sequence.Position reduction;
71 private MyBody(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton, Position reduction) {
74 this.tokens = tokens==null ? emptyForestArray : new Forest[tokens.length];
75 if (tokens != null) System.arraycopy(tokens, 0, this.tokens, 0, tokens.length);
76 if (tokens != null) for(int i=0; i<tokens.length; i++) if (tokens[i]==null) throw new Error(i+"");
78 this.singleton = singleton;
79 this.reduction = reduction;
82 public void expand(final int i, final TreeMaker<T> h) {
84 tokens[0].visit(h, null, i);
87 if (i==0) h.start(tag, location);
89 if (i==tokens.length) {
90 h.finish(tag, location);
92 } else if (unwrap && i==tokens.length-1) {
93 if (tokens[i] != null)
94 tokens[i].visit(h, null, 0);
97 tokens[i].visit(new TreeMaker<T>(h.toss) {
98 public void start(T head, Input.Location loc) { }
99 public void addTree(Tree<T> t) { toks.add(t); }
100 public void finish(T head, Input.Location loc) {
101 int old = h.toks.size();
102 h.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));
104 while(h.toks.size() > old) h.toks.remove(h.toks.size()-1);
110 protected String headToString() { return null; }
111 protected String headToJava() { return null; }
112 protected String left() { return "{"; }
113 protected String right() { return "}"; }
114 protected boolean ignoreSingleton() { return false; }
118 // Ref //////////////////////////////////////////////////////////////////////////////
121 * This class represents a partially complete collection of
122 * forests to be viewed as a forest at some later date; once
123 * viewed, it becomes immutable
125 static class Ref<T> extends Forest<T> {
126 private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
128 public void merge(Forest p) { if (p!=this) hp.add(p, true); }
129 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
130 if (hp==null) return;
131 for(Forest<T> f : hp)
134 public Forest resolve() { return this; }
137 public abstract <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c);
138 private static class TreeMaker2<T> extends TreeMaker<T> {
139 private TreeConsumer<T> tc;
140 public TreeMaker2(boolean toss, TreeConsumer<T> tc) { super(toss); this.tc = tc; }
141 public void finish(T head, Input.Location loc) { tc.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));; }
142 public void start(T head, Input.Location loc) { }
143 public void addTree(Tree<T> t) { toks.add(t); }
145 private static abstract class TreeMaker<T> implements Invokable<Forest.Body<T>,Boolean,Integer>, TreeConsumer<T> {
146 public ArrayList<Tree<T>> toks = new ArrayList<Tree<T>>();
147 private boolean toss;
149 public TreeMaker(boolean toss) { this.toss = toss; }
150 public abstract void start(T head, Input.Location loc);
151 public abstract void finish(T head, Input.Location loc);
152 public abstract void addTree(Tree<T> t);
153 public void invoke(Forest.Body<T> bod, Boolean o, Integer i) {
155 ArrayList<Tree<T>> toks = this.toks;
156 this.toks = new ArrayList<Tree<T>>();
165 // Statics //////////////////////////////////////////////////////////////////////////////
167 private static Tree[] tree_hint = new Tree[0];
168 private static final Forest[] emptyForestArray = new Forest[0];
170 protected String headToString() { return null; }
171 protected String headToJava() { return null; }
172 protected String left() { return "<?"; }
173 protected String right() { return "?>"; }
174 protected boolean ignoreSingleton() { return true; }