1 package edu.berkeley.sbp;
2 import edu.berkeley.sbp.*;
3 import edu.berkeley.sbp.*;
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) {
23 final HashSetTreeConsumer<T> ret = new HashSetTreeConsumer<T>();
24 visit(new TreeMaker2<T>(toss, ret), null, null);
25 if (toss && ret.size() > 1) throw new InnerAmbiguous(this);
29 private static class InnerAmbiguous extends RuntimeException {
30 public final Forest<?> f;
31 public InnerAmbiguous(Forest<?> f) { this.f = f; }
34 public static interface TreeConsumer<T> {
35 public void addTree(Tree<T> t);
37 public static class HashSetTreeConsumer<T> extends HashSet<Tree<T>> implements TreeConsumer<T> {
38 public void addTree(Tree<T> t) { super.add(t); }
41 static <T> Forest<T> singleton(Input.Location loc) { return create(loc, null, new Forest[] { }, false, true); }
42 static <T> Forest<T> singleton(Input.Location loc, Forest<T> body) { return create(loc, null, new Forest[] { body }, false, true); }
43 static <T> Forest<T> leaf(Input.Location loc, T tag) { return create(loc, tag, null, false, false); }
44 public static <T> Forest<T> create(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton) {
45 return new MyBody<T>(loc, tag, tokens, unwrap, singleton);
48 // Body //////////////////////////////////////////////////////////////////////////////
50 protected static interface Body<T> {
51 void expand(int i, TreeMaker<T> h);
54 protected static class MyBody<T> extends Forest<T> implements Body<T> /* extends PrintableTree<Forest<T>> implements */ {
56 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
57 ivbc.invoke(this, b, c);
60 private final Input.Location location;
62 private final Forest<T>[] tokens;
63 private final boolean unwrap;
64 private final boolean singleton;
66 private MyBody(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton) {
69 this.tokens = tokens==null ? emptyForestArray : new Forest[tokens.length];
70 if (tokens != null) System.arraycopy(tokens, 0, this.tokens, 0, tokens.length);
71 if (tokens != null) for(int i=0; i<tokens.length; i++) if (tokens[i]==null) throw new Error(i+"");
73 this.singleton = singleton;
76 public void expand(final int i, final TreeMaker<T> h) {
78 tokens[0].visit(h, null, i);
81 if (i==0) h.start(tag, location);
83 if (i==tokens.length) {
84 h.finish(tag, location);
86 } else if (unwrap && i==tokens.length-1) {
87 if (tokens[i] != null)
88 tokens[i].visit(h, null, 0);
91 tokens[i].visit(new TreeMaker<T>(h.toss) {
92 public void start(T head, Input.Location loc) { }
93 public void addTree(Tree<T> t) { toks.add(t); }
94 public void finish(T head, Input.Location loc) {
95 int old = h.toks.size();
96 h.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));
98 while(h.toks.size() > old) h.toks.remove(h.toks.size()-1);
104 protected String headToString() { return null; }
105 protected String headToJava() { return null; }
106 protected String left() { return "{"; }
107 protected String right() { return "}"; }
108 protected boolean ignoreSingleton() { return false; }
112 // Ref //////////////////////////////////////////////////////////////////////////////
115 * This class represents a partially complete collection of
116 * forests to be viewed as a forest at some later date; once
117 * viewed, it becomes immutable
119 static class Ref<T> extends Forest<T> {
120 private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
122 public void merge(Forest p) { if (p!=this) hp.add(p, true); }
123 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
124 if (hp==null) return;
125 for(Forest<T> f : hp)
128 public Forest resolve() { return this; }
131 public abstract <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c);
132 private static class TreeMaker2<T> extends TreeMaker<T> {
133 private TreeConsumer<T> tc;
134 public TreeMaker2(boolean toss, TreeConsumer<T> tc) { super(toss); this.tc = tc; }
135 public void finish(T head, Input.Location loc) { tc.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));; }
136 public void start(T head, Input.Location loc) { }
137 public void addTree(Tree<T> t) { toks.add(t); }
139 private static abstract class TreeMaker<T> implements Invokable<Forest.Body<T>,Boolean,Integer>, TreeConsumer<T> {
140 public ArrayList<Tree<T>> toks = new ArrayList<Tree<T>>();
141 private boolean toss;
143 public TreeMaker(boolean toss) { this.toss = toss; }
144 public abstract void start(T head, Input.Location loc);
145 public abstract void finish(T head, Input.Location loc);
146 public abstract void addTree(Tree<T> t);
147 public void invoke(Forest.Body<T> bod, Boolean o, Integer i) {
149 ArrayList<Tree<T>> toks = this.toks;
150 this.toks = new ArrayList<Tree<T>>();
159 // Statics //////////////////////////////////////////////////////////////////////////////
161 private static Tree[] tree_hint = new Tree[0];
162 private static final Forest[] emptyForestArray = new Forest[0];
164 protected String headToString() { return null; }
165 protected String headToJava() { return null; }
166 protected String left() { return "<?"; }
167 protected String right() { return "?>"; }
168 protected boolean ignoreSingleton() { return true; }