opensim-development – Blame information for rev 1

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1 eva 1 /*
2 * Copyright (C) 2007-2008, Jeff Thompson
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * * Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * * Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * * Neither the name of the copyright holder nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
22 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
24 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
25 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
26 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
27 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
28 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30  
31 using System;
32 using System.Collections.Generic;
33  
34 namespace OpenSim.Region.ScriptEngine.Shared.YieldProlog
35 {
36 public class Functor2 : IUnifiable
37 {
38 public readonly Atom _name;
39 public readonly object _arg1;
40 public readonly object _arg2;
41  
42 public Functor2(Atom name, object arg1, object arg2)
43 {
44 _name = name;
45 _arg1 = arg1;
46 _arg2 = arg2;
47 }
48  
49 public Functor2(string name, object arg1, object arg2)
50 : this(Atom.a(name), arg1, arg2)
51 {
52 }
53  
54 // disable warning on l1, don't see how we can
55 // code this differently
56 #pragma warning disable 0168, 0219
57 /// If arg is another Functor2, then succeed (yield once) if this and arg have the
58 /// same name and all functor args unify, otherwise fail (don't yield).
59 /// If arg is a Variable, then call its unify to unify with this.
60 /// Otherwise fail (don't yield).
61 public IEnumerable<bool> unify(object arg)
62 {
63 arg = YP.getValue(arg);
64 if (arg is Functor2)
65 {
66 Functor2 argFunctor = (Functor2)arg;
67 if (_name.Equals(argFunctor._name))
68 {
69 foreach (bool l1 in YP.unify(_arg1, argFunctor._arg1))
70 {
71 foreach (bool l2 in YP.unify(_arg2, argFunctor._arg2))
72 yield return false;
73 }
74 }
75 }
76 else if (arg is Variable)
77 {
78 foreach (bool l1 in ((Variable)arg).unify(this))
79 yield return false;
80 }
81 }
82 #pragma warning restore 0168, 0219
83  
84  
85 public override string ToString()
86 {
87 if (_name == Atom.DOT)
88 return listPairToString(this);
89 else
90 return _name + "(" + YP.getValue(_arg1) + ", " + YP.getValue(_arg2) + ")";
91 }
92  
93 public bool termEqual(object term)
94 {
95 term = YP.getValue(term);
96 if (term is Functor2)
97 {
98 Functor2 termFunctor = (Functor2)term;
99 return _name.Equals(termFunctor._name) && YP.termEqual(_arg1, termFunctor._arg1)
100 && YP.termEqual(_arg2, termFunctor._arg2);
101 }
102 return false;
103 }
104  
105 public bool lessThan(Functor2 functor)
106 {
107 // Do the equal check first since it is faster.
108 if (!_name.Equals(functor._name))
109 return _name.lessThan(functor._name);
110  
111 if (!YP.termEqual(_arg1, functor._arg1))
112 return YP.termLessThan(_arg1, functor._arg1);
113  
114 return YP.termLessThan(_arg2, functor._arg2);
115 }
116  
117 public bool ground()
118 {
119 return YP.ground(_arg1) && YP.ground(_arg2);
120 }
121  
122 public void addUniqueVariables(List<Variable> variableSet)
123 {
124 YP.addUniqueVariables(_arg1, variableSet);
125 YP.addUniqueVariables(_arg2, variableSet);
126 }
127  
128 public object makeCopy(Variable.CopyStore copyStore)
129 {
130 return new Functor2(_name, YP.makeCopy(_arg1, copyStore),
131 YP.makeCopy(_arg2, copyStore));
132 }
133  
134 private static string listPairToString(Functor2 listPair)
135 {
136 string result = "[";
137 while (true)
138 {
139 object head = YP.getValue(listPair._arg1);
140 object tail = YP.getValue(listPair._arg2);
141 if (tail == (object)Atom.NIL)
142 {
143 result += head;
144 break;
145 }
146 else if (tail is Functor2 && ((Functor2)tail)._name == Atom.DOT)
147 {
148 result += head + ", ";
149 listPair = (Functor2)tail;
150 // Loop again.
151 }
152 else
153 {
154 // The list is not terminated with NIL.
155 result += head + "|" + tail;
156 break;
157 }
158 }
159 result += "]";
160 return result;
161 }
162 }
163 }