/interpreter/tags/at2dist090708/src/edu/vub/at/objects/natives/NATTypeTag.java

http://ambienttalk.googlecode.com/ · Java · 215 lines · 104 code · 29 blank · 82 comment · 11 complexity · c1471adc882ba91ea5ebb8004678045c 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. */
  28. package edu.vub.at.objects.natives;
  29. import edu.vub.at.actors.natives.DiscoveryManager;
  30. import edu.vub.at.eval.Evaluator;
  31. import edu.vub.at.exceptions.InterpreterException;
  32. import edu.vub.at.objects.ATBoolean;
  33. import edu.vub.at.objects.ATMethod;
  34. import edu.vub.at.objects.ATObject;
  35. import edu.vub.at.objects.ATTable;
  36. import edu.vub.at.objects.ATTypeTag;
  37. import edu.vub.at.objects.coercion.NativeTypeTags;
  38. import edu.vub.at.objects.grammar.ATSymbol;
  39. import edu.vub.at.objects.mirrors.NativeClosure;
  40. import edu.vub.at.objects.natives.grammar.AGSymbol;
  41. /**
  42. * The native implementation of AmbientTalk type tag objects.
  43. *
  44. * In principle, care should be taken that all objects implementing the
  45. * type tag interface are isolates, because type tags are usually attributed
  46. * to messages which are isolates themselves.
  47. *
  48. * @author tvcutsem
  49. */
  50. public class NATTypeTag extends NATByCopy implements ATTypeTag {
  51. private final ATSymbol typeName_;
  52. private final ATTable parentTypes_;
  53. public static ATTypeTag[] toTypeTagArray(ATTable types) throws InterpreterException {
  54. if (types == NATTable.EMPTY) {
  55. return NATObject._NO_TYPETAGS_;
  56. }
  57. ATObject[] unwrapped = types.asNativeTable().elements_;
  58. ATTypeTag[] unwrappedTypes = new ATTypeTag[unwrapped.length];
  59. for (int i = 0; i < unwrappedTypes.length; i++) {
  60. unwrappedTypes[i] = unwrapped[i].asTypeTag();
  61. }
  62. return unwrappedTypes;
  63. }
  64. public static NATTypeTag atValue(String typeName) {
  65. return atValue(AGSymbol.jAlloc(typeName));
  66. }
  67. public static NATTypeTag atValue(ATSymbol typeName) {
  68. return new NATTypeTag(typeName,
  69. NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  70. }
  71. public static NATTypeTag atValue(String typeName, NATTypeTag singleParent) {
  72. return new NATTypeTag(AGSymbol.jAlloc(typeName),
  73. NATTable.atValue(new ATObject[] { singleParent }));
  74. }
  75. /**
  76. * Types should not be created directly because it should be verified
  77. * that their list of parent types is never empty. Types created
  78. * with an empty parent list automatically get assigned the root type
  79. * as their single parent.
  80. */
  81. public static NATTypeTag atValue(ATSymbol typeName, ATTable parentTypes) {
  82. if (parentTypes == NATTable.EMPTY) {
  83. return new NATTypeTag(typeName, NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  84. } else {
  85. return new NATTypeTag(typeName, parentTypes);
  86. }
  87. }
  88. /**
  89. * The constructor is declared protected such that it cannot be used externally,
  90. * but can be used by the OBJRootType class to create a type with an empty
  91. * parent table, which is normally not allowed. Hence, by construction the only
  92. * type with an empty parent table is the root type.
  93. */
  94. protected NATTypeTag(ATSymbol typeName, ATTable parentTypes) {
  95. typeName_ = typeName;
  96. parentTypes_ = parentTypes;
  97. }
  98. public ATSymbol base_typeName() throws InterpreterException {
  99. return typeName_;
  100. }
  101. public ATTable base_superTypes() throws InterpreterException {
  102. return parentTypes_;
  103. }
  104. /**
  105. * Native implementation of:
  106. *
  107. * def isSubtypeOf(supertype) {
  108. * (supertype.name() == name).or:
  109. * { (supertypes.find: { |type|
  110. * type.isSubtypeOf(supertype) }) != nil }
  111. * };
  112. */
  113. public ATBoolean base_isSubtypeOf(final ATTypeTag supertype) throws InterpreterException {
  114. if (supertype.base_typeName().equals(typeName_)) {
  115. return NATBoolean._TRUE_;
  116. } else {
  117. ATObject found = parentTypes_.base_find_(new NativeClosure(this) {
  118. public ATObject base_apply(ATTable args) throws InterpreterException {
  119. ATTypeTag type = get(args, 1).asTypeTag();
  120. return type.base_isSubtypeOf(supertype);
  121. }
  122. });
  123. return NATBoolean.atValue(found != Evaluator.getNil());
  124. }
  125. }
  126. /**
  127. * By default, annotateMessage is the identity function, it does not add any new metadata
  128. * to the message.
  129. */
  130. public ATObject base_annotateMessage(ATObject originalMessage) throws InterpreterException {
  131. return originalMessage;
  132. }
  133. /**
  134. * By default, annotateMethod is the identity function, it does not add any new metadata
  135. * to the method.
  136. */
  137. public ATMethod base_annotateMethod(ATMethod originalMethod) throws InterpreterException {
  138. return originalMethod;
  139. }
  140. /**
  141. * Identity of types is based on their name
  142. */
  143. public ATBoolean base__opeql__opeql_(ATObject comparand) throws InterpreterException {
  144. if (comparand.isTypeTag()) {
  145. return NATBoolean.atValue(comparand.asTypeTag().base_typeName().equals(typeName_));
  146. } else {
  147. return NATBoolean._FALSE_;
  148. }
  149. }
  150. public boolean isTypeTag() { return true; }
  151. public ATTypeTag asTypeTag() { return this; }
  152. public NATText meta_print() throws InterpreterException {
  153. return NATText.atValue("<type tag:"+typeName_+">");
  154. }
  155. /**
  156. * Types are singletons
  157. */
  158. public ATObject meta_clone() throws InterpreterException {
  159. return this;
  160. }
  161. public ATTable meta_typeTags() throws InterpreterException {
  162. return NATTable.of(NativeTypeTags._TYPETAG_, NativeTypeTags._ISOLATE_);
  163. }
  164. /** required as type tags are stored in a hashset in the {@link DiscoveryManager} */
  165. public int hashCode() { return typeName_.hashCode(); }
  166. /**
  167. * The root type of the type hierarchy: every type eventually
  168. * has this type as its parent.
  169. */
  170. public static class OBJRootType extends NATTypeTag implements ATTypeTag {
  171. private final static AGSymbol _ROOT_NAME_ = AGSymbol.jAlloc("Type");
  172. public static final OBJRootType _INSTANCE_ = new OBJRootType();
  173. /**
  174. * The root type is named `Type and has no parent types
  175. */
  176. private OBJRootType() {
  177. super(_ROOT_NAME_, NATTable.EMPTY);
  178. }
  179. /**
  180. * The root type is only a subtype of the root type itself
  181. */
  182. public ATBoolean base_isSubtypeOf(ATTypeTag supertype) throws InterpreterException {
  183. return NATBoolean.atValue(supertype.base_typeName().equals(_ROOT_NAME_));
  184. }
  185. }
  186. }