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

http://ambienttalk.googlecode.com/ · Java · 92 lines · 36 code · 11 blank · 45 comment · 0 complexity · 4f00ebe779d668d40448bdb060bec882 MD5 · raw file

  1. /**
  2. * AmbientTalk/2 Project
  3. * AGTabulation.java created on 26-jul-2006 at 16:19:54
  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.ATExpression;
  33. import edu.vub.at.objects.grammar.ATTabulation;
  34. import edu.vub.at.objects.natives.NATMethodInvocation;
  35. import edu.vub.at.objects.natives.NATTable;
  36. import edu.vub.at.objects.natives.NATText;
  37. /**
  38. * @author tvc
  39. *
  40. * The native implementation of a tabulaton AG element.
  41. */
  42. public final class AGTabulation extends AGExpression implements ATTabulation {
  43. private final ATExpression tblExp_;
  44. private final ATExpression idxExp_;
  45. public AGTabulation(ATExpression tbl, ATExpression idx) {
  46. tblExp_ = tbl;
  47. idxExp_ = idx;
  48. }
  49. public ATExpression base_tableExpression() { return tblExp_; }
  50. public ATExpression base_indexExpression() { return idxExp_; }
  51. /**
  52. * To evaluate a tabulation, evaluate the tabulation expression to a table,
  53. * evaluate the index expression into a valid index, and then access the table at the given index slot.
  54. *
  55. * AGTBL(tbl,idx).eval(ctx) = tbl.eval(ctx).at(idx.eval(ctx))
  56. *
  57. * @return the value of the indexed table slot.
  58. */
  59. public ATObject meta_eval(ATContext ctx) throws InterpreterException {
  60. ATObject col = tblExp_.meta_eval(ctx);
  61. ATObject idx = idxExp_.meta_eval(ctx);
  62. return col.meta_invoke(col,
  63. new NATMethodInvocation(
  64. AGSymbol.jAlloc("at"),
  65. NATTable.of(idx),
  66. NATTable.EMPTY));
  67. }
  68. /**
  69. * Quoting a tabulation results in a new quoted tabulation
  70. *
  71. * AGTBL(tbl,idx).quote(ctx) = AGTBL(tbl.quote(ctx),idx.quote(ctx))
  72. */
  73. public ATObject meta_quote(ATContext ctx) throws InterpreterException {
  74. return new AGTabulation(tblExp_.meta_quote(ctx).asExpression(),
  75. idxExp_.meta_quote(ctx).asExpression());
  76. }
  77. public NATText meta_print() throws InterpreterException {
  78. return NATText.atValue(tblExp_.meta_print().javaValue + "[" +
  79. idxExp_.meta_print().javaValue + "]");
  80. }
  81. }