/interpreter/tags/at2dist091109/src/edu/vub/at/objects/natives/grammar/AGAssignField.java

http://ambienttalk.googlecode.com/ · Java · 118 lines · 54 code · 14 blank · 50 comment · 0 complexity · f99d7ff8efd3dc60efbd933fe01f22b9 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * AGAssignField.java created on 17-aug-2006 at 13:45:32
  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.InvocationStack;
  30. import edu.vub.at.exceptions.InterpreterException;
  31. import edu.vub.at.objects.ATContext;
  32. import edu.vub.at.objects.ATObject;
  33. import edu.vub.at.objects.grammar.ATAssignField;
  34. import edu.vub.at.objects.grammar.ATExpression;
  35. import edu.vub.at.objects.grammar.ATSymbol;
  36. import edu.vub.at.objects.natives.NATTable;
  37. import edu.vub.at.objects.natives.NATText;
  38. import java.util.Set;
  39. /**
  40. * The native implementation of a field assignment AG element.
  41. *
  42. * @author tvc
  43. */
  44. public final class AGAssignField extends NATAbstractGrammar implements ATAssignField {
  45. private final ATExpression rcvExp_;
  46. private final ATSymbol fieldName_;
  47. private final ATExpression valueExp_;
  48. public AGAssignField(ATExpression rcv, ATSymbol nam, ATExpression val) {
  49. rcvExp_ = rcv;
  50. fieldName_ = nam;
  51. valueExp_ = val;
  52. }
  53. public ATExpression base_receiverExpression() { return rcvExp_; }
  54. public ATSymbol base_fieldName() { return fieldName_; }
  55. public ATExpression base_valueExpression() { return valueExp_; }
  56. /**
  57. * To evaluate a field assignment, evaluate the receiver expression, evaluate the right hand side and ask
  58. * the receiver object to assign the RHS value to the field corresponding to the given field name.
  59. *
  60. * In AmbientTalk using the uniform access principle, assignments are represented as message sends.
  61. * For example <tt>o.x := 5</tt> is represented as <tt>o.x:=(5)</tt> where <tt>`x:=</tt> is a special
  62. * selector identifying a field assignment.
  63. *
  64. * AGASSFIELD(rcv,nam,val).eval(ctx) = rcv.eval(ctx).invoke(rcv,nam:=, [ val.eval(ctx) ])
  65. *
  66. * @return the new value of the field
  67. */
  68. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  69. ATObject receiver = rcvExp_.meta_eval(ctx);
  70. NATTable arg = NATTable.of(valueExp_.meta_eval(ctx));
  71. ATObject result = null;
  72. InvocationStack stack = InvocationStack.getInvocationStack();
  73. try {
  74. stack.methodInvoked(this, receiver, arg);
  75. result = receiver.impl_invokeMutator(receiver, fieldName_.asAssignmentSymbol(), arg);
  76. } finally {
  77. stack.methodReturned(result);
  78. }
  79. return result;
  80. }
  81. /**
  82. * AGASSFIELD(rcv,nam,val).quote(ctx) = AGASSFIELD(rcv.quote(ctx), nam.quote(ctx), val.quote(ctx))
  83. */
  84. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  85. return new AGAssignField(rcvExp_.meta_quote(ctx).asExpression(), fieldName_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression());
  86. }
  87. public NATText meta_print() throws InterpreterException {
  88. return NATText.atValue(rcvExp_.meta_print().javaValue + "." + fieldName_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue);
  89. }
  90. /**
  91. * FV(rcvexp.x := exp) = FV(rcvexp) U FV(exp)
  92. */
  93. public Set impl_freeVariables() throws InterpreterException {
  94. Set fvRcvExp = rcvExp_.impl_freeVariables();
  95. fvRcvExp.addAll(valueExp_.impl_freeVariables());
  96. return fvRcvExp;
  97. }
  98. public Set impl_quotedFreeVariables() throws InterpreterException {
  99. Set fvRcvExp = rcvExp_.impl_quotedFreeVariables();
  100. fvRcvExp.addAll(fieldName_.impl_quotedFreeVariables());
  101. fvRcvExp.addAll(valueExp_.impl_quotedFreeVariables());
  102. return fvRcvExp;
  103. }
  104. }