/interpreter/tags/at2dist030708/src/edu/vub/at/objects/natives/grammar/AGDefFunction.java

http://ambienttalk.googlecode.com/ · Java · 162 lines · 84 code · 20 blank · 58 comment · 7 complexity · f898d354b8eee3622c66f339b27b1bcd MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * AGDefFunction.java created on 26-jul-2006 at 15:44:08
  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.grammar;
  29. import edu.vub.at.eval.Evaluator;
  30. import edu.vub.at.exceptions.InterpreterException;
  31. import edu.vub.at.objects.ATContext;
  32. import edu.vub.at.objects.ATMethod;
  33. import edu.vub.at.objects.ATObject;
  34. import edu.vub.at.objects.ATTable;
  35. import edu.vub.at.objects.ATTypeTag;
  36. import edu.vub.at.objects.coercion.NativeTypeTags;
  37. import edu.vub.at.objects.grammar.ATBegin;
  38. import edu.vub.at.objects.grammar.ATDefMethod;
  39. import edu.vub.at.objects.grammar.ATExpression;
  40. import edu.vub.at.objects.grammar.ATSymbol;
  41. import edu.vub.at.objects.natives.NATClosure;
  42. import edu.vub.at.objects.natives.NATMethod;
  43. import edu.vub.at.objects.natives.NATTable;
  44. import edu.vub.at.objects.natives.NATText;
  45. /**
  46. * The native implementation of a function definition abstract grammar element.
  47. * This AG element covers both method and closure definition.
  48. *
  49. * @author tvc
  50. */
  51. public final class AGDefFunction extends NATAbstractGrammar implements ATDefMethod {
  52. private final ATSymbol selectorExp_;
  53. private final ATTable argumentExps_;
  54. private final ATBegin bodyStmts_;
  55. private final ATExpression annotationExps_;
  56. private ATMethod preprocessedMethod_;
  57. public AGDefFunction(ATSymbol sel, ATTable args, ATBegin bdy, ATExpression ann)
  58. throws InterpreterException {
  59. selectorExp_ = sel;
  60. argumentExps_ = args;
  61. bodyStmts_ = bdy;
  62. annotationExps_ = ann;
  63. }
  64. public ATSymbol base_selector() {
  65. return selectorExp_;
  66. }
  67. public ATTable base_arguments() {
  68. return argumentExps_;
  69. }
  70. public ATBegin base_bodyExpression() {
  71. return bodyStmts_;
  72. }
  73. public ATExpression base_annotationExpression() {
  74. return annotationExps_;
  75. }
  76. /**
  77. * Defines a new function (method or closure) in the current scope.
  78. * If a function definition is executed in the context of an object,
  79. * a new method is created. If, however, the function definition
  80. * is executed in the context of a call frame (i.e. its definition
  81. * is nested within a method/function) then a closure is created instead.
  82. *
  83. * The return value of a function definition is always a closure encapsulating the function.
  84. *
  85. * AGDEFFUN(nam,par,bdy).eval(ctx) =
  86. * if ctx.scope.isCallFrame
  87. * ctx.scope.defineField(nam, AGCLO(AGMTH(nam,par,bdy), ctx))
  88. * else
  89. * ctx.scope.addMethod(nam, AGMTH(nam,par,bdy))
  90. *
  91. */
  92. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  93. // the method is not yet created in the constructor because this gives problems
  94. // with quoted parameters: a quoted parameter would result in an illegal parameter
  95. // exception while actually the function was defined in the context of a quotation,
  96. // so at runtime the function definition would have never been evaluated (but quoted instead)
  97. if (preprocessedMethod_ == null) {
  98. ATObject oneOrMoreAnnotation = annotationExps_.meta_eval(ctx);
  99. ATTable annotationTable;
  100. if(oneOrMoreAnnotation.isTable()) {
  101. annotationTable = oneOrMoreAnnotation.asTable();
  102. } else {
  103. annotationTable = NATTable.of(oneOrMoreAnnotation);
  104. }
  105. preprocessedMethod_ = new NATMethod(selectorExp_, argumentExps_, bodyStmts_, annotationTable);
  106. ATObject[] annotations = annotationTable.asNativeTable().elements_;
  107. for (int i = 0; i < annotations.length; i++) {
  108. ATTypeTag theAnnotation = annotations[i].asTypeTag();
  109. preprocessedMethod_ = theAnnotation.base_annotateMethod(preprocessedMethod_);
  110. }
  111. }
  112. ATObject current = ctx.base_lexicalScope();
  113. if (current.isCallFrame()) {
  114. NATClosure clo = new NATClosure(preprocessedMethod_, ctx);
  115. current.meta_defineField(selectorExp_, clo);
  116. return clo;
  117. } else {
  118. current.meta_addMethod(preprocessedMethod_);
  119. return current.meta_select(current, selectorExp_);
  120. }
  121. }
  122. /**
  123. * Quoting a function definition results in a new quoted function definition.
  124. *
  125. * AGDEFFUN(nam,par,bdy).quote(ctx) = AGDEFFUN(nam.quote(ctx), par.quote(ctx), bdy.quote(ctx))
  126. */
  127. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  128. return new AGDefFunction(selectorExp_.meta_quote(ctx).asSymbol(),
  129. argumentExps_.meta_quote(ctx).asTable(),
  130. bodyStmts_.meta_quote(ctx).asBegin(),
  131. annotationExps_.meta_quote(ctx).asExpression());
  132. }
  133. public NATText meta_print() throws InterpreterException {
  134. return NATText.atValue("def " +
  135. selectorExp_.meta_print().javaValue +
  136. Evaluator.printAsList(argumentExps_).javaValue +
  137. " { " + bodyStmts_.meta_print().javaValue + " }");
  138. }
  139. public ATTable meta_typeTags() throws InterpreterException {
  140. return NATTable.of(NativeTypeTags._METHOD_DEFINITION_, NativeTypeTags._ISOLATE_);
  141. }
  142. }