/interpreter/tags/at2-build060407/src/edu/vub/at/objects/natives/grammar/AGAssignVariable.java

http://ambienttalk.googlecode.com/ · Java · 93 lines · 36 code · 11 blank · 46 comment · 0 complexity · 9d7c712a8deb2cd146a485aa3dec7c6a 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.exceptions.InterpreterException;
  30. import edu.vub.at.exceptions.XTypeMismatch;
  31. import edu.vub.at.objects.ATContext;
  32. import edu.vub.at.objects.ATObject;
  33. import edu.vub.at.objects.grammar.ATAssignVariable;
  34. import edu.vub.at.objects.grammar.ATExpression;
  35. import edu.vub.at.objects.grammar.ATSymbol;
  36. import edu.vub.at.objects.natives.NATText;
  37. /**
  38. * @author tvc
  39. *
  40. * The native implementation of a variable assignment AG element.
  41. * Examples:
  42. * <tt>x := 5</tt>
  43. * <tt>+ := m()</tt>
  44. */
  45. public final class AGAssignVariable extends NATAbstractGrammar implements ATAssignVariable {
  46. private final ATSymbol variableName_;
  47. private final ATExpression valueExp_;
  48. public AGAssignVariable(ATSymbol nam, ATExpression val) {
  49. variableName_ = nam;
  50. valueExp_ = val;
  51. }
  52. public ATSymbol base_getName() { return variableName_; }
  53. public ATExpression base_getValueExpression() { return valueExp_; }
  54. /**
  55. * To evaluate a variable assignment, evaluate the right hand side and ask
  56. * the current object to assign that value to the field corresponding to the left hand side.
  57. *
  58. * AGASSVAR(nam,val).eval(ctx) = ctx.scope.assignVariable(nam, val.eval(ctx))
  59. *
  60. * @return the value assigned to the variable
  61. */
  62. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  63. ATObject val = valueExp_.meta_eval(ctx);
  64. ctx.base_getLexicalScope().meta_assignVariable(variableName_, val);
  65. return val;
  66. }
  67. /**
  68. * AGASSVAR(nam,val).quote(ctx) = AGASSVAR(nam.quote(ctx), val.quote(ctx))
  69. */
  70. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  71. return new AGAssignVariable(variableName_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression());
  72. }
  73. public NATText meta_print() throws InterpreterException {
  74. return NATText.atValue(variableName_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue);
  75. }
  76. public boolean isVariableAssignment() {
  77. return true;
  78. }
  79. public ATAssignVariable asVariableAssignment() throws XTypeMismatch {
  80. return this;
  81. }
  82. }