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1 package ppg.atoms;
2
3 import java.util.*;
4
5 public class SymbolList
6 {
7 public static final int TERMINAL = 0;
8 public static final int NONTERMINAL = 1;
9
10 private int variety;
11 private String  type;
12 private Vector symbols;
13
14 public SymbolList(int which, String type, Vector syms) {
15 variety = which;
16 this.type = type;
17 symbols = syms;
18 }
19
20 public boolean dropSymbol (String gs) {
21 for (int i=0; i < symbols.size(); i++) {
22 if (gs.equals(symbols.elementAt(i))) {
23 symbols.removeElementAt(i);
24 return true;
26 }
27 }
28 return false;
29 }
30
31 public Object clone() {
32 String newType = (type == null) ? null : type.toString();
33 Vector newSyms = new Vector();
34 for (int i=0; i < symbols.size(); i++) {
35 newSyms.addElement( ((String )symbols.elementAt(i)).toString() );
36 }
37 return new SymbolList(variety, newType, newSyms);
38 }
39
40 public String toString() {
41 String result = "";
42
43 if (symbols.size() > 0) {
44 switch (variety) {
45 case (TERMINAL): result = "terminal "; break;
46 case (NONTERMINAL): result = "non terminal "; break;
47 }
48
49 if (type != null)
50 result += type + " ";
51
52 int size = symbols.size();
53 for (int i=0; i < size; i++) {
54 result += (String )symbols.elementAt(i);
55 if (i < size - 1)
56 result += ", ";
57 }
58 result += ";";
59 }
60
61 return result;
62 }
63 }
64 |
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