ILSpy/ICSharpCode.Decompiler/CSharp/Syntax/PatternMatching/Backreference.cs

// Copyright (c) 2011-2013 AlphaSierraPapa for the SharpDevelop Team
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
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// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
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using System;
using System.Linq;

namespace ICSharpCode.Decompiler.CSharp.Syntax.PatternMatching
{
	/// <summary>
	/// Matches the last entry in the specified named group.
	/// </summary>
	public class Backreference : Pattern
	{
		readonly string referencedGroupName;
		
		public string ReferencedGroupName {
			get { return referencedGroupName; }
		}
		
		public Backreference(string referencedGroupName)
		{
			if (referencedGroupName == null)
				throw new ArgumentNullException("referencedGroupName");
			this.referencedGroupName = referencedGroupName;
		}
		
		public override bool DoMatch(INode other, Match match)
		{
			var last = match.Get (referencedGroupName).LastOrDefault();
			if (last == null && other == null)
				return true;
			return last.IsMatch(other);
		}
	}
}