/interpreter/tags/reactive-pattern-matching/src/edu/vub/at/objects/natives/NATTypeTag.java
Java | 215 lines | 104 code | 29 blank | 82 comment | 11 complexity | bfcf593d5983c236cee4f6a5ebb1a32d MD5 | raw file
1/** 2 * AmbientTalk/2 Project 3 * NATTypeTag.java created on 18-feb-2007 at 15:59:20 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.actors.natives.DiscoveryManager; 31import edu.vub.at.eval.Evaluator; 32import edu.vub.at.exceptions.InterpreterException; 33import edu.vub.at.objects.ATBoolean; 34import edu.vub.at.objects.ATMethod; 35import edu.vub.at.objects.ATObject; 36import edu.vub.at.objects.ATTable; 37import edu.vub.at.objects.ATTypeTag; 38import edu.vub.at.objects.coercion.NativeTypeTags; 39import edu.vub.at.objects.grammar.ATSymbol; 40import edu.vub.at.objects.mirrors.NativeClosure; 41import edu.vub.at.objects.natives.grammar.AGSymbol; 42 43/** 44 * The native implementation of AmbientTalk type tag objects. 45 * 46 * In principle, care should be taken that all objects implementing the 47 * type tag interface are isolates, because type tags are usually attributed 48 * to messages which are isolates themselves. 49 * 50 * @author tvcutsem 51 */ 52public class NATTypeTag extends NATByCopy implements ATTypeTag { 53 54 protected final ATSymbol typeName_; 55 protected final ATTable parentTypes_; 56 57 public static ATTypeTag[] toTypeTagArray(ATTable types) throws InterpreterException { 58 if (types == NATTable.EMPTY) { 59 return NATObject._NO_TYPETAGS_; 60 } 61 ATObject[] unwrapped = types.asNativeTable().elements_; 62 ATTypeTag[] unwrappedTypes = new ATTypeTag[unwrapped.length]; 63 for (int i = 0; i < unwrappedTypes.length; i++) { 64 unwrappedTypes[i] = unwrapped[i].asTypeTag(); 65 } 66 return unwrappedTypes; 67 } 68 69 public static NATTypeTag atValue(String typeName) { 70 return atValue(AGSymbol.jAlloc(typeName)); 71 } 72 73 public static NATTypeTag atValue(ATSymbol typeName) { 74 return new NATTypeTag(typeName, 75 NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ })); 76 } 77 78 public static NATTypeTag atValue(String typeName, NATTypeTag singleParent) { 79 return new NATTypeTag(AGSymbol.jAlloc(typeName), 80 NATTable.atValue(new ATObject[] { singleParent })); 81 } 82 83 /** 84 * Types should not be created directly because it should be verified 85 * that their list of parent types is never empty. Types created 86 * with an empty parent list automatically get assigned the root type 87 * as their single parent. 88 */ 89 public static NATTypeTag atValue(ATSymbol typeName, ATTable parentTypes) { 90 if (parentTypes == NATTable.EMPTY) { 91 return new NATTypeTag(typeName, NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ })); 92 } else { 93 return new NATTypeTag(typeName, parentTypes); 94 } 95 } 96 97 /** 98 * The constructor is declared protected such that it cannot be used externally, 99 * but can be used by the OBJRootType class to create a type with an empty 100 * parent table, which is normally not allowed. Hence, by construction the only 101 * type with an empty parent table is the root type. 102 */ 103 protected NATTypeTag(ATSymbol typeName, ATTable parentTypes) { 104 typeName_ = typeName; 105 parentTypes_ = parentTypes; 106 } 107 108 public ATSymbol base_typeName() throws InterpreterException { 109 return typeName_; 110 } 111 112 public ATTable base_superTypes() throws InterpreterException { 113 return parentTypes_; 114 } 115 116 /** 117 * Native implementation of: 118 * 119 * def isSubtypeOf(supertype) { 120 * (supertype.name() == name).or: 121 * { (supertypes.find: { |type| 122 * type.isSubtypeOf(supertype) }) != nil } 123 * }; 124 */ 125 public ATBoolean base_isSubtypeOf(final ATTypeTag supertype) throws InterpreterException { 126 if (supertype.base_typeName().equals(typeName_)) { 127 return NATBoolean._TRUE_; 128 } else { 129 ATObject found = parentTypes_.base_find_(new NativeClosure(this) { 130 public ATObject base_apply(ATTable args) throws InterpreterException { 131 ATTypeTag type = get(args, 1).asTypeTag(); 132 return type.base_isSubtypeOf(supertype); 133 } 134 }); 135 return NATBoolean.atValue(found != Evaluator.getNil()); 136 } 137 } 138 139 /** 140 * By default, annotateMessage is the identity function, it does not add any new metadata 141 * to the message. 142 */ 143 public ATObject base_annotateMessage(ATObject originalMessage) throws InterpreterException { 144 return originalMessage; 145 } 146 147 /** 148 * By default, annotateMethod is the identity function, it does not add any new metadata 149 * to the method. 150 */ 151 public ATMethod base_annotateMethod(ATMethod originalMethod) throws InterpreterException { 152 return originalMethod; 153 } 154 155 156 /** 157 * Identity of types is based on their name 158 */ 159 public ATBoolean base__opeql__opeql_(ATObject comparand) throws InterpreterException { 160 if (comparand.isTypeTag()) { 161 return comparand.asTypeTag().base_typeName().base__opeql__opeql_(typeName_); 162 } else { 163 return NATBoolean._FALSE_; 164 } 165 } 166 167 public boolean isTypeTag() { return true; } 168 169 public ATTypeTag asTypeTag() { return this; } 170 171 public NATText meta_print() throws InterpreterException { 172 return NATText.atValue("<type tag:"+typeName_+">"); 173 } 174 175 /** 176 * Types are singletons 177 */ 178 public ATObject meta_clone() throws InterpreterException { 179 return this; 180 } 181 182 public ATTable meta_typeTags() throws InterpreterException { 183 return NATTable.of(NativeTypeTags._TYPETAG_, NativeTypeTags._ISOLATE_); 184 } 185 186 /** required as type tags are stored in a hashset in the {@link DiscoveryManager} */ 187 public int hashCode() { return typeName_.hashCode(); } 188 189 /** 190 * The root type of the type hierarchy: every type eventually 191 * has this type as its parent. 192 */ 193 public static class OBJRootType extends NATTypeTag implements ATTypeTag { 194 195 private final static AGSymbol _ROOT_NAME_ = AGSymbol.jAlloc("Type"); 196 197 public static final OBJRootType _INSTANCE_ = new OBJRootType(); 198 199 /** 200 * The root type is named `Type and has no parent types 201 */ 202 private OBJRootType() { 203 super(_ROOT_NAME_, NATTable.EMPTY); 204 } 205 206 /** 207 * The root type is only a subtype of the root type itself 208 */ 209 public ATBoolean base_isSubtypeOf(ATTypeTag supertype) throws InterpreterException { 210 return NATBoolean.atValue(supertype.base_typeName().equals(_ROOT_NAME_)); 211 } 212 213 } 214 215}