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

http://ambienttalk.googlecode.com/ · Java · 99 lines · 45 code · 11 blank · 43 comment · 0 complexity · 13463c6906eb5c6fad390038f2e95c25 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * AGAssignVariable.java created on 26-jul-2006 at 15:54:48
  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.exceptions.XTypeMismatch;
  32. import edu.vub.at.objects.ATContext;
  33. import edu.vub.at.objects.ATObject;
  34. import edu.vub.at.objects.grammar.ATAssignVariable;
  35. import edu.vub.at.objects.grammar.ATExpression;
  36. import edu.vub.at.objects.grammar.ATSymbol;
  37. import edu.vub.at.objects.natives.NATTable;
  38. import edu.vub.at.objects.natives.NATText;
  39. /**
  40. * The native implementation of a variable assignment AG element.
  41. *
  42. * @author tvc
  43. */
  44. public final class AGAssignVariable extends NATAbstractGrammar implements ATAssignVariable {
  45. private final ATSymbol variableName_;
  46. private final ATExpression valueExp_;
  47. public AGAssignVariable(ATSymbol nam, ATExpression val) {
  48. variableName_ = nam;
  49. valueExp_ = val;
  50. }
  51. public ATSymbol base_name() { return variableName_; }
  52. public ATExpression base_valueExpression() { return valueExp_; }
  53. /**
  54. * To evaluate a variable assignment, evaluate the right hand side and ask
  55. * the current object to assign that value to the field corresponding to the left hand side.
  56. *
  57. * AGASSVAR(nam,val).eval(ctx) = ctx.scope.assignVariable(nam, val.eval(ctx))
  58. *
  59. * @return the value assigned to the variable
  60. */
  61. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  62. NATTable arg = NATTable.of(valueExp_.meta_eval(ctx));
  63. ATObject result = null;
  64. InvocationStack stack = InvocationStack.getInvocationStack();
  65. try {
  66. stack.functionCalled(this, null, arg);
  67. result = ctx.base_lexicalScope().impl_callMutator(variableName_.asAssignmentSymbol(), arg);
  68. } finally {
  69. stack.funcallReturned(result);
  70. }
  71. return result;
  72. }
  73. /**
  74. * AGASSVAR(nam,val).quote(ctx) = AGASSVAR(nam.quote(ctx), val.quote(ctx))
  75. */
  76. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  77. return new AGAssignVariable(variableName_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression());
  78. }
  79. public NATText meta_print() throws InterpreterException {
  80. return NATText.atValue(variableName_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue);
  81. }
  82. public boolean isVariableAssignment() {
  83. return true;
  84. }
  85. public ATAssignVariable asVariableAssignment() throws XTypeMismatch {
  86. return this;
  87. }
  88. }