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

http://ambienttalk.googlecode.com/ · Java · 114 lines · 47 code · 14 blank · 53 comment · 0 complexity · 324cdc884bc4a9ce6d9143962b42cc90 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * AGDefField.java created on 26-jul-2006 at 12:14:43
  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.objects.ATContext;
  31. import edu.vub.at.objects.ATObject;
  32. import edu.vub.at.objects.grammar.ATDefField;
  33. import edu.vub.at.objects.grammar.ATDefinition;
  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. import java.util.HashSet;
  38. import java.util.Set;
  39. /**
  40. * @author tvc
  41. *
  42. * AGDefField represents the abstract grammar for defining fields.
  43. * Examples:
  44. * <tt>x := 5</tt>
  45. * <tt>+ := "foo"</tt>
  46. */
  47. public final class AGDefField extends AGDefinition implements ATDefField {
  48. private final ATSymbol name_;
  49. private final ATExpression valueExp_;
  50. public AGDefField(ATSymbol name, ATExpression value) {
  51. name_ = name;
  52. valueExp_ = value;
  53. }
  54. public ATSymbol base_name() { return name_; }
  55. public ATExpression base_valueExpression() { return valueExp_; }
  56. /**
  57. * Defines a new field in the current scope. The return value is
  58. * the evaluated value.
  59. *
  60. * AGDEFFIELD(nam,val).eval(ctx) =
  61. * ctx.scope.addField(nam, val.eval(ctx))
  62. */
  63. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  64. ATObject val = valueExp_.meta_eval(ctx);
  65. ctx.base_lexicalScope().meta_defineField(name_, val);
  66. return val;
  67. }
  68. /**
  69. * Quoting a field definition results in a new quoted field definition.
  70. *
  71. * AGDEFFIELD(nam,val).quote(ctx) = AGDEFFIELD(nam.quote(ctx), val.quote(ctx))
  72. */
  73. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  74. return new AGDefField(name_.meta_quote(ctx).asSymbol(), valueExp_.meta_quote(ctx).asExpression());
  75. }
  76. public NATText meta_print() throws InterpreterException {
  77. return NATText.atValue("def " + name_.meta_print().javaValue + " := " + valueExp_.meta_print().javaValue);
  78. }
  79. /**
  80. * IV(def x := val) = { x }
  81. */
  82. public Set impl_introducedVariables() throws InterpreterException {
  83. HashSet singleton = new HashSet();
  84. singleton.add(name_);
  85. return singleton;
  86. }
  87. /**
  88. * FV(def var := exp) = FV(exp) \ { var }
  89. */
  90. public Set impl_freeVariables() throws InterpreterException {
  91. Set fvValueExp = valueExp_.impl_freeVariables();
  92. fvValueExp.remove(name_);
  93. return fvValueExp;
  94. }
  95. public Set impl_quotedFreeVariables() throws InterpreterException {
  96. Set qfv = valueExp_.impl_quotedFreeVariables();
  97. qfv.addAll(name_.impl_quotedFreeVariables());
  98. return qfv;
  99. }
  100. }