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1
3 package ro.infoiasi.donald.compiler.parser;
4
5 import ro.infoiasi.donald.compiler.cfg.*;
6
7 public class LR1Item {
8 private LR0Item lr0item;
9 private Terminal lookahead;
10
11 public LR1Item(LR0Item lr0item, Terminal lookahead) {
12 this.lr0item = lr0item;
13 this.lookahead = lookahead;
14 }
15
16 public boolean equals(Object  o) {
17 return (o instanceof LR1Item &&
18 lr0item.equals(((LR1Item)o).lr0item) &&
19 lookahead == ((LR1Item)o).lookahead);
20 }
21
22 public int hashCode() {
23 return 17+lr0item.hashCode()*37+lookahead.hashCode();
24 }
25
26 public LR1Item nextItem() {
27 return new LR1Item(lr0item.nextItem(), lookahead);
28 }
29
30 public boolean isComplete() {
31 return lr0item.isComplete();
32 }
33
34 public boolean isNew() {
35 return lr0item.isNew();
36 }
37
38 public Symbol getNextSymbol() {
39 return lr0item.getNextSymbol();
40 }
41
42 public Word getSufixAndLookahead() {
43 if (!getNextSymbol().isTerminal()) {
44 Word w = new Word(lr0item.suffix());
45 w.removeFirst();
46 w.addLast(lookahead);
47 return w;
48 } else {
49 throw new UnsupportedOperationException ();
50 }
51 }
52
53 public LR0Item getLR0Item() {
54 return lr0item;
55 }
56
57 public Production getProduction() {
58 return lr0item.getProduction();
59 }
60
61 public int getPosition() {
62 return lr0item.getPosition();
63 }
64
65 public Terminal getLookahead() {
66 return lookahead;
67 }
68
69 public String toString() {
70 return "("+lr0item+", "+lookahead+")";
71 }
72 }
73 |
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