/interpreter/tags/at2dist030708/src/edu/vub/at/objects/natives/NATBoolean.java
Java | 185 lines | 102 code | 42 blank | 41 comment | 2 complexity | 0d0791e65bf7f59534159146cda909be MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * NATBoolean.java created on Jul 23, 2006 at 12:52:29 PM 4 * (c) Programming Technology Lab, 2006 - 2007 5 * Authors: Tom Van Cutsem & Stijn Mostinckx 6 * 7 * Permission is hereby granted, free of charge, to any person 8 * obtaining a copy of this software and associated documentation 9 * files (the "Software"), to deal in the Software without 10 * restriction, including without limitation the rights to use, 11 * copy, modify, merge, publish, distribute, sublicense, and/or 12 * sell copies of the Software, and to permit persons to whom the 13 * Software is furnished to do so, subject to the following 14 * conditions: 15 * 16 * The above copyright notice and this permission notice shall be 17 * included in all copies or substantial portions of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 20 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 21 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 22 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 23 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 24 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 25 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 26 * OTHER DEALINGS IN THE SOFTWARE. 27 */ 28package edu.vub.at.objects.natives; 29 30import edu.vub.at.eval.Evaluator; 31import edu.vub.at.exceptions.InterpreterException; 32import edu.vub.at.objects.ATBoolean; 33import edu.vub.at.objects.ATClosure; 34import edu.vub.at.objects.ATObject; 35import edu.vub.at.objects.ATTable; 36import edu.vub.at.objects.coercion.NativeTypeTags; 37 38/** 39 * NATBoolean is simply a container class for ambienttalk booleans. The native 40 * implementations of true and false can be accessed using the class's atValue 41 * method. 42 * 43 * @author smostinc 44 */ 45public abstract class NATBoolean extends NATByCopy implements ATBoolean { 46 47 /** 48 * Returns the corresponding ATBoolean given a java truth value. This constructor 49 * function is to be used only when the result to be given out depends on a 50 * dynamic test, else the static fields _TRUE_ and _FALSE_ should be used instead. 51 */ 52 public static ATBoolean atValue(boolean b) { 53 if (b) { 54 return _TRUE_; 55 } else { 56 return _FALSE_; 57 } 58 } 59 60 public final boolean javaValue; 61 62 private NATBoolean(boolean b) { 63 javaValue = b; 64 } 65 66 public boolean isNativeBoolean() { 67 return true; 68 } 69 70 public ATBoolean asBoolean() { 71 return this; 72 } 73 74 public NATBoolean asNativeBoolean() { 75 return this; 76 } 77 78 public ATObject meta_clone() throws InterpreterException { 79 return this; 80 } 81 82 public ATTable meta_typeTags() throws InterpreterException { 83 return NATTable.of(NativeTypeTags._BOOLEAN_, NativeTypeTags._ISOLATE_); 84 } 85 86 public static class NATTrue extends NATBoolean { 87 88 public static final NATTrue _INSTANCE_ = new NATTrue(); 89 90 public NATTrue() { super(true); } 91 92 public NATText meta_print() throws InterpreterException { return NATText.atValue("true"); } 93 94 // base interface for true 95 96 public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException { 97 return clo.base_apply(NATTable.EMPTY); 98 } 99 100 public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException { 101 return Evaluator.getNil(); 102 } 103 104 public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException { 105 return consequent.base_apply(NATTable.EMPTY); 106 } 107 108 public ATBoolean base_and_(ATClosure other) throws InterpreterException { 109 return other.base_apply(NATTable.EMPTY).asBoolean(); 110 } 111 112 public ATBoolean base_or_(ATClosure other) throws InterpreterException { 113 return this; 114 } 115 116 public ATBoolean base_and_and_(ATClosure b1, ATClosure b2) throws InterpreterException { 117 return b1.base_apply(NATTable.EMPTY).asBoolean().base_and_(b2); 118 } 119 120 public ATBoolean base_or_or_(ATClosure b1, ATClosure b2) throws InterpreterException { 121 return this; 122 } 123 124 public ATBoolean base_not() { 125 return NATFalse._INSTANCE_; 126 } 127 128 public ATObject meta_resolve() throws InterpreterException { 129 return NATTrue._INSTANCE_; 130 } 131 132 } 133 134 public static class NATFalse extends NATBoolean { 135 136 public static final NATFalse _INSTANCE_ = new NATFalse(); 137 138 public NATFalse() { super(false); } 139 140 public NATText meta_print() throws InterpreterException { return NATText.atValue("false"); } 141 142 // base interface for false 143 144 public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException { 145 return Evaluator.getNil(); 146 } 147 148 public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException { 149 return clo.base_apply(NATTable.EMPTY); 150 } 151 152 public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException { 153 return alternative.base_apply(NATTable.EMPTY); 154 } 155 156 public ATBoolean base_and_(ATClosure other) throws InterpreterException { 157 return this; 158 } 159 160 public ATBoolean base_or_(ATClosure other) throws InterpreterException { 161 return other.base_apply(NATTable.EMPTY).asBoolean(); 162 } 163 164 public ATBoolean base_not() { 165 return NATTrue._INSTANCE_; 166 } 167 168 public ATBoolean base_and_and_(ATClosure b1, ATClosure b2) throws InterpreterException { 169 return this; 170 } 171 172 public ATBoolean base_or_or_(ATClosure b1, ATClosure b2) throws InterpreterException { 173 return b1.base_apply(NATTable.EMPTY).asBoolean().base_or_(b2); 174 } 175 176 public ATObject meta_resolve() throws InterpreterException { 177 return NATFalse._INSTANCE_; 178 } 179 180 } 181 182 public static final NATTrue _TRUE_ = NATTrue._INSTANCE_; 183 public static final NATFalse _FALSE_ = NATFalse._INSTANCE_; 184 185}