/interpreter/tags/at2dist110511/src/edu/vub/at/objects/natives/NATBoolean.java

  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 java.util.HashMap;
 31
 32import edu.vub.at.eval.Evaluator;
 33import edu.vub.at.exceptions.InterpreterException;
 34import edu.vub.at.objects.ATBoolean;
 35import edu.vub.at.objects.ATClosure;
 36import edu.vub.at.objects.ATObject;
 37import edu.vub.at.objects.ATTable;
 38import edu.vub.at.objects.coercion.NativeTypeTags;
 39import edu.vub.util.TempFieldGenerator;
 40
 41/**
 42 * NATBoolean is simply a container class for ambienttalk booleans. The native 
 43 * implementations of true and false can be accessed using the class's atValue
 44 * method.
 45 * 
 46 * @author smostinc
 47 */
 48public abstract class NATBoolean extends NATByCopy implements ATBoolean {
 49	
 50	/**
 51	 * Returns the corresponding ATBoolean given a java truth value. This constructor
 52	 * function is to be used only when the result to be given out depends on a 
 53	 * dynamic test, else the static fields _TRUE_ and _FALSE_ should be used instead.
 54	 */
 55	public static ATBoolean atValue(boolean b) {
 56		if (b) {
 57			return _TRUE_;
 58		} else {
 59			return _FALSE_;
 60		}
 61	}
 62	
 63	public final boolean javaValue;
 64	
 65	private NATBoolean(boolean b) {
 66		javaValue = b;
 67	}
 68	
 69	public boolean isNativeBoolean() {
 70		return true;
 71	}
 72
 73	public ATBoolean asBoolean() {
 74		return this;
 75	}
 76	
 77	public NATBoolean asNativeBoolean() {
 78		return this;
 79	}
 80	
 81	public ATObject meta_clone() throws InterpreterException {
 82		return this;
 83	}
 84	
 85    public ATTable meta_typeTags() throws InterpreterException {
 86    	return NATTable.of(NativeTypeTags._BOOLEAN_, NativeTypeTags._ISOLATE_);
 87    }
 88	
 89	public static class NATTrue extends NATBoolean {
 90		
 91		public static final NATTrue _INSTANCE_ = new NATTrue();
 92		
 93		public NATTrue() { super(true); }
 94		
 95		public NATText meta_print() throws InterpreterException { return NATText.atValue("true"); }
 96		
 97		public NATText impl_asCode(TempFieldGenerator objectMap) throws InterpreterException {
 98			if (objectMap.contains(this)) {
 99				return objectMap.getName(this);
100			}
101			NATText name = objectMap.put(this, NATText.atValue("true"));
102			return name;
103		}
104		
105		// base interface for true
106		
107		public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException {
108			return clo.base_apply(NATTable.EMPTY);
109		}
110
111		public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException {
112			return Evaluator.getNil();
113		}
114		
115		public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException {
116			return consequent.base_apply(NATTable.EMPTY);
117		}
118		
119		public ATBoolean base_and_(ATClosure other) throws InterpreterException {
120			return other.base_apply(NATTable.EMPTY).asBoolean();
121		}
122		
123		public ATBoolean base_or_(ATClosure other) throws InterpreterException {
124			return this;
125		}
126		
127		public ATBoolean base_and_and_(ATClosure b1, ATClosure b2) throws InterpreterException {
128			return b1.base_apply(NATTable.EMPTY).asBoolean().base_and_(b2);
129		}
130
131		public ATBoolean base_or_or_(ATClosure b1, ATClosure b2) throws InterpreterException {
132			return this;
133		}
134
135		public ATBoolean base_not() {
136			return NATFalse._INSTANCE_;
137		}
138		
139		public ATObject meta_resolve() throws InterpreterException {
140			return NATTrue._INSTANCE_;
141		}
142		
143	}
144
145	public static class NATFalse extends NATBoolean {
146		
147		public static final NATFalse _INSTANCE_ = new NATFalse();
148		
149		public NATFalse() { super(false); }
150		
151		public NATText meta_print() throws InterpreterException { return NATText.atValue("false"); }
152		
153		public NATText impl_asCode(TempFieldGenerator objectMap) throws InterpreterException {
154			if (objectMap.contains(this)) {
155				return objectMap.getName(this);
156			}
157			NATText name = objectMap.put(this, NATText.atValue("false"));
158			return name; 
159		}
160
161		// base interface for false
162		
163		public ATObject base_ifTrue_(ATClosure clo) throws InterpreterException {
164			return Evaluator.getNil();
165		}
166
167		public ATObject base_ifFalse_(ATClosure clo) throws InterpreterException {
168			return clo.base_apply(NATTable.EMPTY);
169		}
170		
171		public ATObject base_ifTrue_ifFalse_(ATClosure consequent, ATClosure alternative) throws InterpreterException {
172			return alternative.base_apply(NATTable.EMPTY);
173		}
174		
175		public ATBoolean base_and_(ATClosure other) throws InterpreterException {
176			return this;
177		}
178		
179		public ATBoolean base_or_(ATClosure other) throws InterpreterException {
180			return other.base_apply(NATTable.EMPTY).asBoolean();
181		}
182		
183		public ATBoolean base_not() {
184			return NATTrue._INSTANCE_;
185		}
186		
187		public ATBoolean base_and_and_(ATClosure b1, ATClosure b2) throws InterpreterException {
188			return this;
189		}
190
191		public ATBoolean base_or_or_(ATClosure b1, ATClosure b2) throws InterpreterException {
192			return b1.base_apply(NATTable.EMPTY).asBoolean().base_or_(b2);
193		}
194		
195		public ATObject meta_resolve() throws InterpreterException {
196			return NATFalse._INSTANCE_;
197		}
198		
199	}
200	
201	public static final NATTrue _TRUE_ = NATTrue._INSTANCE_;
202	public static final NATFalse _FALSE_ = NATFalse._INSTANCE_;
203	
204}