EQ2EMu/EQ2/devtools/EQ2ModelViewer/EQ2ModelViewer/Spart/Parsers/NonTerminal/Rule.cs

/// Spart License (zlib/png)
/// 
/// 
/// Copyright (c) 2003 Jonathan de Halleux
/// 
/// This software is provided 'as-is', without any express or implied warranty. 
/// In no event will the authors be held liable for any damages arising from 
/// the use of this software.
/// 
/// Permission is granted to anyone to use this software for any purpose, 
/// including commercial applications, and to alter it and redistribute it 
/// freely, subject to the following restrictions:
/// 
/// 1. The origin of this software must not be misrepresented; you must not 
/// claim that you wrote the original software. If you use this software in a 
/// product, an acknowledgment in the product documentation would be 
/// appreciated but is not required.
/// 
/// 2. Altered source versions must be plainly marked as such, and must not be 
/// misrepresented as being the original software.
/// 
/// 3. This notice may not be removed or altered from any source distribution.
/// 
/// Author: Jonathan de Halleuxnamespace Spart.Parsers.NonTerminal

namespace Spart.Parsers.NonTerminal
{
	using System;
	using Spart.Actions;
	using Spart.Scanners;

	/// <summary>
	/// A rule is a parser holder.
	/// </summary>
	public class Rule : NonTerminalParser
	{
		private Parser m_Parser;

		/// <summary>
		/// Empty rule creator
		/// </summary>
		public Rule()
			: base()
		{
			Parser = null;
		}

		/// <summary>
		/// Creates a rule and assign parser
		/// </summary>
		/// <param name="p"></param>
		public Rule(Parser p)
			: base()
		{
			Parser = p;
		}

		/// <summary>
		/// Rule parser
		/// </summary>
		public Parser Parser
		{
			get
			{
				return m_Parser;
			}
			set
			{
				if( m_Parser != value )
					m_Parser = value;
			}
		}

		/// <summary>
		/// Assign a parser to a rule, if r is null, a new rule is created
		/// </summary>
		/// <param name="r"></param>
		/// <param name="p"></param>
		/// <returns></returns>
		public static Rule AssignParser(Rule r, Parser p)
		{
			if (r==null)
			{
				r = new Rule(p);
				return r; 
			}
			r.Parser = p;
			return r;
		}

		/// <summary>
		/// Parse the input
		/// </summary>
		/// <param name="scanner"></param>
		/// <returns></returns>
		public override ParserMatch Parse(IScanner scanner)
		{
			if (scanner == null)
				throw new ArgumentNullException("scanner");

			OnPreParse(scanner);
			ParserMatch match = ParseMain(scanner);
			OnPostParse(match,scanner);

			if (!match.Success)
				return match;

			OnAction(match);
			return match;
		}

		/// <summary>
		/// Inner parse method
		/// </summary>
		/// <param name="scanner"></param>
		/// <returns></returns>
		public override ParserMatch ParseMain(IScanner scanner)
		{
			if (scanner == null)
				throw new ArgumentNullException("scanner");

			if (Parser != null)
				return Parser.Parse(scanner);
			else
				return scanner.NoMatch;
		}


        public override Parser Clone()
        {
            Rule clone = base.Clone() as Rule;
            clone.m_Parser = m_Parser.Clone();

            return clone;
        }
	}
}