Experiments/Attic/Rook/Castle.Rook.Compiler/Parser/antlr/ASTPair.cs

   1 namespace antlr
   2 {
   3         using System;
   4         using Queue = System.Collections.Queue;
   5         using AST       = antlr.collections.AST;
   6
   7         /*ANTLR Translator Generator
   8         * Project led by Terence Parr at http://www.jGuru.com
   9         * Software rights: http://www.antlr.org/license.html
  10         *
  11         * $Id:$
  12         */
  13
  14         //
  15         // ANTLR C# Code Generator by Micheal Jordan
  16         //                            Kunle Odutola       : kunle UNDERSCORE odutola AT hotmail DOT com
  17         //                            Anthony Oguntimehin
  18         //
  19         // With many thanks to Eric V. Smith from the ANTLR list.
  20         //
  21
  22
  23         /*ASTPair:  utility class used for manipulating a pair of ASTs
  24         * representing the current AST root and current AST sibling.
  25         * This exists to compensate for the lack of pointers or 'var'
  26         * arguments in Java.
  27         */
  28
  29         public class ASTPair
  30         {
  31                 static private Queue instancePool_ = new Queue();
  32
  33                 static public ASTPair GetInstance()
  34                 {
  35                         if (instancePool_.Count > 0)
  36                         {
  37                                 return (ASTPair) instancePool_.Dequeue();
  38                         }
  39                         return new ASTPair();
  40                 }
  41
  42                 static public void PutInstance(ASTPair p)
  43                 {
  44                         if (p != null)
  45                         {
  46                                 p.reset();
  47                                 instancePool_.Enqueue(p);
  48                         }
  49                 }
  50
  51                 public AST root; // current root of tree
  52                 public AST child; // current child to which siblings are added
  53
  54                 /*Make sure that child is the last sibling */
  55                 public void  advanceChildToEnd()
  56                 {
  57                         if (child != null)
  58                         {
  59                                 while (child.getNextSibling() != null)
  60                                 {
  61                                         child = child.getNextSibling();
  62                                 }
  63                         }
  64                 }
  65
  66                 /*Copy an ASTPair.  Don't call it clone() because we want type-safety */
  67                 public virtual ASTPair copy()
  68                 {
  69                         ASTPair tmp = ASTPair.GetInstance();
  70                         tmp.root = root;
  71                         tmp.child = child;
  72                         return tmp;
  73                 }
  74
  75                 private void reset()
  76                 {
  77                         root  = null;
  78                         child = null;
  79                 }
  80
  81                 override public string ToString()
  82                 {
  83                         string r = (root == null) ? "null" : root.getText();
  84                         string c = (child == null) ? "null" : child.getText();
  85                         return "[" + r + "," + c + "]";
  86                 }
  87         }
  88 }