source: trunk/yao/share/antlr-2.7.7/lib/csharp/antlr.runtime/antlr/ASTPair.cs @ 1

namespace antlr
{
        using System;
        using Queue = System.Collections.Queue;
        using AST       = antlr.collections.AST;

        /*ANTLR Translator Generator
        * Project led by Terence Parr at http://www.jGuru.com
        * Software rights: http://www.antlr.org/license.html
        *
        * $Id:$
        */

        //
        // ANTLR C# Code Generator by Micheal Jordan
        //                            Kunle Odutola       : kunle UNDERSCORE odutola AT hotmail DOT com
        //                            Anthony Oguntimehin
        //
        // With many thanks to Eric V. Smith from the ANTLR list.
        //


        /*ASTPair:  utility class used for manipulating a pair of ASTs
        * representing the current AST root and current AST sibling.
        * This exists to compensate for the lack of pointers or 'var'
        * arguments in Java.
        */

        public struct ASTPair
        {
                public AST root; // current root of tree
                public AST child; // current child to which siblings are added
                
                /*Make sure that child is the last sibling */
                public void  advanceChildToEnd()
                {
                        if (child != null)
                        {
                                while (child.getNextSibling() != null)
                                {
                                        child = child.getNextSibling();
                                }
                        }
                }
                
                /*Copy an ASTPair.  Don't call it clone() because we want type-safety */
                public ASTPair copy()
                {
                        ASTPair tmp = new ASTPair();
                        tmp.root = root;
                        tmp.child = child;
                        return tmp;
                }

                private void reset()
                {
                        root  = null;
                        child = null;
                }
                
                override public string ToString()
                {
                        string r = (root == null) ? "null" : root.getText();
                        string c = (child == null) ? "null" : child.getText();
                        return "[" + r + "," + c + "]";
                }
        }
}