1 /*
2 * The contents of this file are subject to the BT "ZEUS" Open Source
3 * Licence (L77741), Version 1.0 (the "Licence"); you may not use this file
4 * except in compliance with the Licence. You may obtain a copy of the Licence
5 * from $ZEUS_INSTALL/licence.html or alternatively from
6 * http://www.labs.bt.com/projects/agents/zeus/licence.htm
7 *
8 * Except as stated in Clause 7 of the Licence, software distributed under the
9 * Licence is distributed WITHOUT WARRANTY OF ANY KIND, either express or
10 * implied. See the Licence for the specific language governing rights and
11 * limitations under the Licence.
12 *
13 * The Original Code is within the package zeus.*.
14 * The Initial Developer of the Original Code is British Telecommunications
15 * public limited company, whose registered office is at 81 Newgate Street,
16 * London, EC1A 7AJ, England. Portions created by British Telecommunications
17 * public limited company are Copyright 1996-9. All Rights Reserved.
18 *
19 * THIS NOTICE MUST BE INCLUDED ON ANY COPY OF THIS FILE
20 */
21
22
23
24 package zeus.concepts.fn;
25
26 import java.util.*;
27 import zeus.util.*;
28 import zeus.concepts.*;
29
30 public class TypeFn extends ValueFunction implements PrimitiveFn {
31 protected String arg = null;
32
33 public TypeFn(String arg) {
34 super(TYPE,10);
35 this.arg = arg;
36 }
37 public ValueFunction mirror() {
38 return new TypeFn(arg);
39 }
40 public String toString() {
41 return arg;
42 }
43 Object getArg(int position) {
44 if (position != 0) throw new ArrayIndexOutOfBoundsException(position);
45 return arg;
46 }
47 String getBase() {
48 return arg.substring(1); // ignore preceding Fact.F_CHR
49 }
50 public ValueFunction duplicate(DuplicationTable table) {
51 // Example @man12 => @var101
52
53 String base = arg.substring(1); // ignore preceding Fact.F_CHR
54 base = table.getRef(base);
55 String result = "" + arg.charAt(0) + base;
56 return new TypeFn(result);
57 }
58 public boolean references(ValueFunction var) {
59 return false;
60 }
61 public boolean isDeterminate() {
62 return true;
63 }
64 public boolean equals(Object any) {
65 if ( !(any instanceof TypeFn) ) return false;
66 TypeFn fn = (TypeFn)any;
67 return arg.equals(fn.getArg());
68 }
69 public boolean less(Object fn) {
70 return false;
71 }
72
73 ValueFunction unify(ValueFunction fn, Bindings b) {
74 return null;
75 }
76 }