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>>, IntegerMappable {
12 private static int master_idx = 0;
13 private final int idx = master_idx++;
14 public int toInt() { return idx; }
16 /** assume that this forest contains exactly one tree and return it; otherwise throw an exception */
17 public final Tree<T> expand1() throws Ambiguous, ParseFailed {
19 Iterator<Tree<T>> it = expand(true).iterator();
20 if (!it.hasNext()) throw new ParseFailed();
22 } catch (InnerAmbiguous ia) { throw new Ambiguous(ia.f); }
25 /** expand this forest into a set of trees */
26 public HashSet<Tree<T>> expand(boolean toss) {
28 final HashSetTreeConsumer<T> ret = new HashSetTreeConsumer<T>();
29 visit(new TreeMaker2<T>(toss, ret), null, null);
30 if (toss && ret.size() > 1) throw new InnerAmbiguous(this);
34 private static class InnerAmbiguous extends RuntimeException {
35 public final Forest<?> f;
36 public InnerAmbiguous(Forest<?> f) { this.f = f; }
39 public static interface TreeConsumer<T> {
40 public void addTree(Tree<T> t);
42 public static class HashSetTreeConsumer<T> extends HashSet<Tree<T>> implements TreeConsumer<T> {
43 public void addTree(Tree<T> t) { super.add(t); }
46 static <T> Forest<T> singleton(Input.Location loc, Position p) {
47 return create(loc, null, new Forest[] { }, false, true, p); }
48 static <T> Forest<T> singleton(Input.Location loc, Forest<T> body, Position p) {
49 return create(loc, null, new Forest[] { body }, false, true, p); }
50 static <T> Forest<T> leaf(Input.Location loc, T tag, Position p) { return create(loc, tag, null, false, false, p); }
52 public static <T> Forest<T> create(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton, Position p) {
53 return new MyBody<T>(loc, tag, tokens, unwrap, singleton, p);
56 // Body //////////////////////////////////////////////////////////////////////////////
58 protected static interface Body<T> {
59 void expand(int i, TreeMaker<T> h);
62 protected static class MyBody<T> extends Forest<T> implements Body<T> /* extends PrintableTree<Forest<T>> implements */ {
64 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
65 ivbc.invoke(this, b, c);
68 private final Input.Location location;
70 private final Forest<T>[] tokens;
71 private final boolean unwrap;
72 private final boolean singleton;
73 private final Sequence.Position reduction;
75 private MyBody(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton, Position reduction) {
78 this.tokens = tokens==null ? emptyForestArray : new Forest[tokens.length];
79 if (tokens != null) System.arraycopy(tokens, 0, this.tokens, 0, tokens.length);
80 if (tokens != null) for(int i=0; i<tokens.length; i++) if (tokens[i]==null) throw new Error(i+"");
82 this.singleton = singleton;
83 this.reduction = reduction;
86 public void expand(final int i, final TreeMaker<T> h) {
88 tokens[0].visit(h, null, i);
91 if (i==0) h.start(tag, location);
93 if (i==tokens.length) {
94 h.finish(tag, location);
96 } else if (unwrap && i==tokens.length-1) {
97 if (tokens[i] != null)
98 tokens[i].visit(h, null, 0);
101 tokens[i].visit(new TreeMaker<T>(h.toss) {
102 public void start(T head, Input.Location loc) { }
103 public void addTree(Tree<T> t) { toks.add(t); }
104 public void finish(T head, Input.Location loc) {
105 int old = h.toks.size();
106 h.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));
108 while(h.toks.size() > old) h.toks.remove(h.toks.size()-1);
114 protected String headToString() { return null; }
115 protected String headToJava() { return null; }
116 protected String left() { return "{"; }
117 protected String right() { return "}"; }
118 protected boolean ignoreSingleton() { return false; }
122 // Ref //////////////////////////////////////////////////////////////////////////////
125 * This class represents a partially complete collection of
126 * forests to be viewed as a forest at some later date; once
127 * viewed, it becomes immutable
129 static class Ref<T> extends Forest<T> {
130 private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
133 if (hp.size()==1) return hp.iterator().next().toInt();
134 return super.toInt();
136 public void merge(Forest p) { if (p!=this) hp.add(p, true); }
137 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
138 if (hp==null) return;
139 for(Forest<T> f : hp)
142 public Forest resolve() { return this; }
145 public abstract <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c);
146 private static class TreeMaker2<T> extends TreeMaker<T> {
147 private TreeConsumer<T> tc;
148 public TreeMaker2(boolean toss, TreeConsumer<T> tc) { super(toss); this.tc = tc; }
149 public void finish(T head, Input.Location loc) { tc.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));; }
150 public void start(T head, Input.Location loc) { }
151 public void addTree(Tree<T> t) { toks.add(t); }
153 private static abstract class TreeMaker<T> implements Invokable<Forest.Body<T>,Boolean,Integer>, TreeConsumer<T> {
154 public ArrayList<Tree<T>> toks = new ArrayList<Tree<T>>();
155 private boolean toss;
157 public TreeMaker(boolean toss) { this.toss = toss; }
158 public abstract void start(T head, Input.Location loc);
159 public abstract void finish(T head, Input.Location loc);
160 public abstract void addTree(Tree<T> t);
161 public void invoke(Forest.Body<T> bod, Boolean o, Integer i) {
163 ArrayList<Tree<T>> toks = this.toks;
164 this.toks = new ArrayList<Tree<T>>();
173 // Statics //////////////////////////////////////////////////////////////////////////////
175 private static Tree[] tree_hint = new Tree[0];
176 private static final Forest[] emptyForestArray = new Forest[0];
178 protected String headToString() { return null; }
179 protected String headToJava() { return null; }
180 protected String left() { return "<?"; }
181 protected String right() { return "?>"; }
182 protected boolean ignoreSingleton() { return true; }