/interpreter/tags/at2-build270707/src/edu/vub/at/objects/natives/NATBoolean.java
Java | 168 lines | 89 code | 38 blank | 41 comment | 2 complexity | 057167152f89b20cc63d513fb1f0a0c2 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.exceptions.InterpreterException; 31import edu.vub.at.objects.ATBoolean; 32import edu.vub.at.objects.ATClosure; 33import edu.vub.at.objects.ATObject; 34import edu.vub.at.objects.ATTable; 35import edu.vub.at.objects.coercion.NativeTypeTags; 36 37/** 38 * NATBoolean is simply a container class for ambienttalk booleans. The native 39 * implementations of true and false can be accessed using the class's atValue 40 * method. 41 * 42 * @author smostinc 43 */ 44public abstract class NATBoolean extends NATByCopy implements ATBoolean { 45 46 /** 47 * Returns the corresponding ATBoolean given a java truth value. This constructor 48 * function is to be used only when the result to be given out depends on a 49 * dynamic test, else the static fields _TRUE_ and _FALSE_ should be used instead. 50 */ 51 public static ATBoolean atValue(boolean b) { 52 if (b) { 53 return _TRUE_; 54 } else { 55 return _FALSE_; 56 } 57 } 58 59 public final boolean javaValue; 60 61 private NATBoolean(boolean b) { 62 javaValue = b; 63 } 64 65 public boolean isNativeBoolean() { 66 return true; 67 } 68 69 public ATBoolean asBoolean() { 70 return this; 71 } 72 73 public NATBoolean asNativeBoolean() { 74 return this; 75 } 76 77 public ATObject meta_clone() throws InterpreterException { 78 return this; 79 } 80 81 public ATTable meta_typeTags() throws InterpreterException { 82 return NATTable.of(NativeTypeTags._BOOLEAN_, NativeTypeTags._ISOLATE_); 83 } 84 85 public static class NATTrue extends NATBoolean { 86 87 public static NATTrue _INSTANCE_ = new NATTrue(); 88 89 public NATTrue() { super(true); } 90 91 public NATText meta_print() throws InterpreterException { return NATText.atValue("true"); } 92 93 // base interface for true 94 95 public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException { 96 return clo.base_apply(NATTable.EMPTY); 97 } 98 99 public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException { 100 return OBJNil._INSTANCE_; 101 } 102 103 public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException { 104 return consequent.base_apply(NATTable.EMPTY); 105 } 106 107 public ATBoolean base_and_(ATClosure other) throws InterpreterException { 108 return other.base_apply(NATTable.EMPTY).asBoolean(); 109 } 110 111 public ATBoolean base_or_(ATClosure other) throws InterpreterException { 112 return this; 113 } 114 115 public ATBoolean base_not() { 116 return NATFalse._INSTANCE_; 117 } 118 119 public ATObject meta_resolve() throws InterpreterException { 120 return NATTrue._INSTANCE_; 121 } 122 123 } 124 125 public static class NATFalse extends NATBoolean { 126 127 public static NATFalse _INSTANCE_ = new NATFalse(); 128 129 public NATFalse() { super(false); } 130 131 public NATText meta_print() throws InterpreterException { return NATText.atValue("false"); } 132 133 // base interface for false 134 135 public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException { 136 return OBJNil._INSTANCE_; 137 } 138 139 public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException { 140 return clo.base_apply(NATTable.EMPTY); 141 } 142 143 public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException { 144 return alternative.base_apply(NATTable.EMPTY); 145 } 146 147 public ATBoolean base_and_(ATClosure other) throws InterpreterException { 148 return this; 149 } 150 151 public ATBoolean base_or_(ATClosure other) throws InterpreterException { 152 return other.base_apply(NATTable.EMPTY).asBoolean(); 153 } 154 155 public ATBoolean base_not() { 156 return NATTrue._INSTANCE_; 157 } 158 159 public ATObject meta_resolve() throws InterpreterException { 160 return NATFalse._INSTANCE_; 161 } 162 163 } 164 165 public static final NATTrue _TRUE_ = NATTrue._INSTANCE_; 166 public static final NATFalse _FALSE_ = NATFalse._INSTANCE_; 167 168}