DemoParser.cs

//Generated by the GOLD Parser Builder

using System;
using System.IO;
using System.Text;

namespace BefunDebug
{
	internal class DemoParser
	{
		private GOLD.Parser parser = new GOLD.Parser();

		public GOLD.Reduction Root;     //Store the top of the tree
		public string FailMessage;

		public long Time;

		public bool Setup(BinaryReader FilePath)
		{
			try
			{
				return parser.LoadTables(FilePath);
			}
			catch (Exception e)
			{
				FailMessage = e.Message;
				return false;
			}
		}

		public bool Parse(TextReader reader, ref string tree, bool Trim)
		{
			Time = Environment.TickCount;

			GOLD.ParseMessage response;
			bool done;                      //Controls when we leave the loop
			bool accepted = false;          //Was the parse successful?

			parser.Open(reader);
			parser.TrimReductions = Trim;  //Please read about this feature before enabling

			done = false;
			while (!done)
			{
				response = parser.Parse();

				switch (response)
				{
					case GOLD.ParseMessage.LexicalError:
						//Cannot recognize token
						FailMessage = "Lexical Error:" + Environment.NewLine +
						              "Position: " + (parser.CurrentPosition().Line + 1) + ", " + parser.CurrentPosition().Column + Environment.NewLine +
						              "Read: " + parser.CurrentToken().Data;
						done = true;
						break;

					case GOLD.ParseMessage.SyntaxError:
						//Expecting a different token
						FailMessage = "Syntax Error:" + Environment.NewLine +
						              "Position: " + (parser.CurrentPosition().Line + 1) + ", " + parser.CurrentPosition().Column + Environment.NewLine +
						              "Read: " + parser.CurrentToken().Data + Environment.NewLine +
						              "Expecting: " + parser.ExpectedSymbols().Text();
						done = true;
						break;

					case GOLD.ParseMessage.Reduction:
						GOLD.Reduction r = (GOLD.Reduction)parser.CurrentReduction;
						break;

					case GOLD.ParseMessage.Accept:
						//Accepted!
						Root = (GOLD.Reduction)parser.CurrentReduction;    //The root node!
						done = true;
						accepted = true;
						break;

					case GOLD.ParseMessage.TokenRead:
						//You don't have to do anything here.
						break;

					case GOLD.ParseMessage.InternalError:
						//INTERNAL ERROR! Something is horribly wrong.
						FailMessage = "Internal Error";
						done = true;
						break;

					case GOLD.ParseMessage.NotLoadedError:
						//This error occurs if the CGT was not loaded.
						FailMessage = "Tables not loaded";
						done = true;
						break;

					case GOLD.ParseMessage.GroupError:
						//GROUP ERROR! Unexpected end of file
						FailMessage = "Runaway group";
						done = true;
						break;
				}
			} //while

			if (accepted)
			{
				tree = DrawReductionTree(Root);
			}
			else
			{
				tree = FailMessage;
			}

			Time = Environment.TickCount - Time;

			return accepted;
		}

		private string DrawReductionTree(GOLD.Reduction Root)
		{
			//This procedure starts the recursion that draws the parse tree.
			StringBuilder tree = new StringBuilder();

			tree.AppendLine("+-" + Root.Parent.Text(false));
			DrawReduction(tree, Root, 1);

			return tree.ToString();
		}

		private void DrawReduction(StringBuilder tree, GOLD.Reduction reduction, int indent)
		{
			//This is a simple recursive procedure that draws an ASCII version of the parse
			//tree

			int n;
			string indentText = "";

			for (n = 1; n <= indent; n++)
			{
				indentText += "| ";
			}

			//=== Display the children of the reduction
			for (n = 0; n < reduction.Count(); n++)
			{
				switch (reduction[n].Type())
				{
					case GOLD.SymbolType.Nonterminal:
						GOLD.Reduction branch = (GOLD.Reduction)reduction[n].Data;

						tree.AppendLine(indentText + "+-" + branch.Parent.Text(false));
						DrawReduction(tree, branch, indent + 1);
						break;

					default:
						string leaf = (string)reduction[n].Data;

						tree.AppendLine(indentText + "+-" + leaf);
						break;
				}
			}
		}
	};
} //MyParser