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 {
14 Iterator<Tree<T>> it = expand(true).iterator();
15 if (!it.hasNext()) throw new ParseFailed();
19 /** expand this forest into a set of trees */
20 public HashSet<Tree<T>> expand(boolean toss) {
21 final HashSetTreeConsumer<T> ret = new HashSetTreeConsumer<T>();
22 visit(new TreeMaker2<T>(toss, ret), null, null);
23 if (toss && ret.size() > 1) throw new Ambiguous(this);
27 public static interface TreeConsumer<T> {
28 public void addTree(Tree<T> t);
30 public static class HashSetTreeConsumer<T> extends HashSet<Tree<T>> implements TreeConsumer<T> {
31 public void addTree(Tree<T> t) { super.add(t); }
34 static <T> Forest<T> singleton(Input.Location loc) { return create(loc, null, new Forest[] { }, false, true); }
35 static <T> Forest<T> singleton(Input.Location loc, Forest<T> body) { return create(loc, null, new Forest[] { body }, false, true); }
36 static <T> Forest<T> leaf(Input.Location loc, T tag) { return create(loc, tag, null, false, false); }
37 public static <T> Forest<T> create(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton) {
38 return new MyBody<T>(loc, tag, tokens, unwrap, singleton);
41 // Body //////////////////////////////////////////////////////////////////////////////
43 protected static interface Body<T> {
44 void expand(int i, TreeMaker<T> h);
47 protected static class MyBody<T> extends Forest<T> implements Body<T> /* extends PrintableTree<Forest<T>> implements */ {
49 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
50 ivbc.invoke(this, b, c);
53 private final Input.Location location;
55 private final Forest<T>[] tokens;
56 private final boolean unwrap;
57 private final boolean singleton;
59 private MyBody(Input.Location loc, T tag, Forest<T>[] tokens, boolean unwrap, boolean singleton) {
62 this.tokens = tokens==null ? emptyForestArray : new Forest[tokens.length];
63 if (tokens != null) System.arraycopy(tokens, 0, this.tokens, 0, tokens.length);
64 if (tokens != null) for(int i=0; i<tokens.length; i++) if (tokens[i]==null) throw new Error(i+"");
66 this.singleton = singleton;
69 public void expand(final int i, final TreeMaker<T> h) {
71 tokens[0].visit(h, null, i);
74 if (i==0) h.start(tag, location);
76 if (i==tokens.length) {
77 h.finish(tag, location);
79 } else if (unwrap && i==tokens.length-1) {
80 if (tokens[i] != null)
81 tokens[i].visit(h, null, 0);
84 tokens[i].visit(new TreeMaker<T>(h.toss) {
85 public void start(T head, Input.Location loc) { }
86 public void addTree(Tree<T> t) { toks.add(t); }
87 public void finish(T head, Input.Location loc) {
88 int old = h.toks.size();
89 h.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));
91 while(h.toks.size() > old) h.toks.remove(h.toks.size()-1);
97 protected String headToString() { return null; }
98 protected String headToJava() { return null; }
99 protected String left() { return "{"; }
100 protected String right() { return "}"; }
101 protected boolean ignoreSingleton() { return false; }
105 // Ref //////////////////////////////////////////////////////////////////////////////
108 * This class represents a partially complete collection of
109 * forests to be viewed as a forest at some later date; once
110 * viewed, it becomes immutable
112 static class Ref<T> extends Forest<T> {
113 private FastSet<Forest<T>> hp = new FastSet<Forest<T>>();
115 public void merge(Forest p) { if (p!=this) hp.add(p, true); }
116 public <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c) {
117 if (hp==null) return;
118 for(Forest<T> f : hp)
121 public Forest resolve() { return this; }
124 public abstract <B,C> void visit(Invokable<Forest.Body<T>,B,C> ivbc, B b, C c);
125 private static class TreeMaker2<T> extends TreeMaker<T> {
126 private TreeConsumer<T> tc;
127 public TreeMaker2(boolean toss, TreeConsumer<T> tc) { super(toss); this.tc = tc; }
128 public void finish(T head, Input.Location loc) { tc.addTree(new Tree<T>(loc, head, toks.toArray(tree_hint)));; }
129 public void start(T head, Input.Location loc) { }
130 public void addTree(Tree<T> t) { toks.add(t); }
132 private static abstract class TreeMaker<T> implements Invokable<Forest.Body<T>,Boolean,Integer>, TreeConsumer<T> {
133 public ArrayList<Tree<T>> toks = new ArrayList<Tree<T>>();
134 private boolean toss;
136 public TreeMaker(boolean toss) { this.toss = toss; }
137 public abstract void start(T head, Input.Location loc);
138 public abstract void finish(T head, Input.Location loc);
139 public abstract void addTree(Tree<T> t);
140 public void invoke(Forest.Body<T> bod, Boolean o, Integer i) {
142 ArrayList<Tree<T>> toks = this.toks;
143 this.toks = new ArrayList<Tree<T>>();
152 // Statics //////////////////////////////////////////////////////////////////////////////
154 private static Tree[] tree_hint = new Tree[0];
155 private static final Forest[] emptyForestArray = new Forest[0];
157 protected String headToString() { return null; }
158 protected String headToJava() { return null; }
159 protected String left() { return "<?"; }
160 protected String right() { return "?>"; }
161 protected boolean ignoreSingleton() { return true; }