/interpreter/tags/at2-build270707/src/edu/vub/at/objects/natives/NATTypeTag.java

http://ambienttalk.googlecode.com/ · Java · 192 lines · 94 code · 25 blank · 73 comment · 11 complexity · cbf1b050e101ffc9332a61b4c2fd266e 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.exceptions.InterpreterException;
  30. import edu.vub.at.objects.ATBoolean;
  31. import edu.vub.at.objects.ATObject;
  32. import edu.vub.at.objects.ATTable;
  33. import edu.vub.at.objects.ATTypeTag;
  34. import edu.vub.at.objects.coercion.NativeTypeTags;
  35. import edu.vub.at.objects.grammar.ATSymbol;
  36. import edu.vub.at.objects.mirrors.NativeClosure;
  37. import edu.vub.at.objects.natives.grammar.AGSymbol;
  38. /**
  39. * The native implementation of AmbientTalk type tag objects.
  40. *
  41. * In principle, care should be taken that all objects implementing the
  42. * type tag interface are isolates, because type tags are usually attributed
  43. * to messages which are isolates themselves.
  44. *
  45. * @author tvcutsem
  46. */
  47. public class NATTypeTag extends NATByCopy implements ATTypeTag {
  48. private final ATSymbol typeName_;
  49. private final ATTable parentTypes_;
  50. public static ATTypeTag[] toTypeTagArray(ATTable types) throws InterpreterException {
  51. if (types == NATTable.EMPTY) {
  52. return NATObject._NO_TYPETAGS_;
  53. }
  54. ATObject[] unwrapped = types.asNativeTable().elements_;
  55. ATTypeTag[] unwrappedTypes = new ATTypeTag[unwrapped.length];
  56. for (int i = 0; i < unwrappedTypes.length; i++) {
  57. unwrappedTypes[i] = unwrapped[i].asTypeTag();
  58. }
  59. return unwrappedTypes;
  60. }
  61. public static NATTypeTag atValue(String typeName) {
  62. return atValue(AGSymbol.jAlloc(typeName));
  63. }
  64. public static NATTypeTag atValue(ATSymbol typeName) {
  65. return new NATTypeTag(typeName,
  66. NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  67. }
  68. public static NATTypeTag atValue(String typeName, NATTypeTag singleParent) {
  69. return new NATTypeTag(AGSymbol.jAlloc(typeName),
  70. NATTable.atValue(new ATObject[] { singleParent }));
  71. }
  72. /**
  73. * Types should not be created directly because it should be verified
  74. * that their list of parent types is never empty. Types created
  75. * with an empty parent list automatically get assigned the root type
  76. * as their single parent.
  77. */
  78. public static NATTypeTag atValue(ATSymbol typeName, ATTable parentTypes) {
  79. if (parentTypes == NATTable.EMPTY) {
  80. return new NATTypeTag(typeName, NATTable.atValue(new ATObject[] { OBJRootType._INSTANCE_ }));
  81. } else {
  82. return new NATTypeTag(typeName, parentTypes);
  83. }
  84. }
  85. /**
  86. * The constructor is declared protected such that it cannot be used externally,
  87. * but can be used by the OBJRootType class to create a type with an empty
  88. * parent table, which is normally not allowed. Hence, by construction the only
  89. * type with an empty parent table is the root type.
  90. */
  91. protected NATTypeTag(ATSymbol typeName, ATTable parentTypes) {
  92. typeName_ = typeName;
  93. parentTypes_ = parentTypes;
  94. }
  95. public ATSymbol base_typeName() throws InterpreterException {
  96. return typeName_;
  97. }
  98. public ATTable base_superTypes() throws InterpreterException {
  99. return parentTypes_;
  100. }
  101. /**
  102. * Native implementation of:
  103. *
  104. * def isSubtypeOf(supertype) {
  105. * (supertype.name() == name).or:
  106. * { (supertypes.find: { |type|
  107. * type.isSubtypeOf(supertype) }) != nil }
  108. * };
  109. */
  110. public ATBoolean base_isSubtypeOf(final ATTypeTag supertype) throws InterpreterException {
  111. if (supertype.base_typeName().equals(typeName_)) {
  112. return NATBoolean._TRUE_;
  113. } else {
  114. ATObject found = parentTypes_.base_find_(new NativeClosure(this) {
  115. public ATObject base_apply(ATTable args) throws InterpreterException {
  116. ATTypeTag type = get(args, 1).asTypeTag();
  117. return type.base_isSubtypeOf(supertype);
  118. }
  119. });
  120. return NATBoolean.atValue(found != OBJNil._INSTANCE_);
  121. }
  122. }
  123. /**
  124. * Identity of types is based on their name
  125. */
  126. public ATBoolean base__opeql__opeql_(ATObject comparand) throws InterpreterException {
  127. if (comparand.isTypeTag()) {
  128. return comparand.asTypeTag().base_typeName().base__opeql__opeql_(typeName_);
  129. } else {
  130. return NATBoolean._FALSE_;
  131. }
  132. }
  133. public boolean isTypeTag() { return true; }
  134. public ATTypeTag asTypeTag() { return this; }
  135. public NATText meta_print() throws InterpreterException {
  136. return NATText.atValue("<type tag:"+typeName_+">");
  137. }
  138. /**
  139. * Types are singletons
  140. */
  141. public ATObject meta_clone() throws InterpreterException {
  142. return this;
  143. }
  144. public ATTable meta_typeTags() throws InterpreterException {
  145. return NATTable.of(NativeTypeTags._TYPETAG_, NativeTypeTags._ISOLATE_);
  146. }
  147. /**
  148. * The root type of the type hierarchy: every type eventually
  149. * has this type as its parent.
  150. */
  151. public static class OBJRootType extends NATTypeTag implements ATTypeTag {
  152. private final static AGSymbol _ROOT_NAME_ = AGSymbol.jAlloc("Type");
  153. public static final OBJRootType _INSTANCE_ = new OBJRootType();
  154. /**
  155. * The root type is named `Type and has no parent types
  156. */
  157. private OBJRootType() {
  158. super(_ROOT_NAME_, NATTable.EMPTY);
  159. }
  160. /**
  161. * The root type is only a subtype of the root type itself
  162. */
  163. public ATBoolean base_isSubtypeOf(ATTypeTag supertype) throws InterpreterException {
  164. return NATBoolean.atValue(supertype.base_typeName().equals(_ROOT_NAME_));
  165. }
  166. }
  167. }