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

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

        //
        // ANTLR C# Code Generator by Micheal Jordan
        //                            Kunle Odutola       : kunle UNDERSCORE odutola AT hotmail DOT com
        //                            Anthony Oguntimehin
        //

        using System;
        using StringBuilder     = System.Text.StringBuilder;
        using AST                               = antlr.collections.AST;

        public abstract class ParseTree : BaseAST
        {
                /// <summary>
                /// Walk parse tree and return requested number of derivation steps.
                /// If steps less-than 0, return node text.  If steps equals 1, return derivation
                /// string at step.
                /// </summary>
                /// <param name="step">derivation steps</param>
                /// <returns></returns>
                public string getLeftmostDerivationStep(int step) 
                {
                        if ( step <= 0 ) 
                        {
                                return ToString();
                        }
                        StringBuilder buf = new StringBuilder (2000);
                        getLeftmostDerivation(buf, step);
                        return buf.ToString();
                }

                public string getLeftmostDerivation(int maxSteps)
                {
                        StringBuilder buf = new StringBuilder(2000);
                        buf.Append("    " + this.ToString());
                        buf.Append("\n");
                        for (int d=1; d < maxSteps; d++) 
                        {
                                buf.Append(" =>");
                                buf.Append(getLeftmostDerivationStep(d));
                                buf.Append("\n");
                        }
                        return buf.ToString();
                }

                /// <summary>
                /// Get derivation and return how many you did (less than requested for
                /// subtree roots.
                /// </summary>
                /// <param name="buf">string buffer</param>
                /// <param name="step">derivation steps</param>
                /// <returns></returns>
                protected internal abstract int getLeftmostDerivation(StringBuilder buf, int step);

                // just satisfy BaseAST interface; unused as we manually create nodes

                public override void initialize(int i, string s) 
                {
                }
                
                public override void initialize(AST ast) 
                {
                }
                
                public override void initialize(IToken token) 
                {
                }
        }
}