Tuple.cs

 using System.Diagnostics;
 
 public interface ITuple
 {
 	int Length
	{
		get;
	}
 	
 	object this[int index]
 	{
 		get;
 	}
 }
 
 public class Tuple<T> : ITuple
 {
 	public int Length
	{
		get
		{
			return 1;
		}
	}
 	
 	public object this[int index]
 	{
 		get
 		{
 		    Debug.Assert(index == 0);
 		    return m_item;
 		}
 	}
 	
 	public Tuple(T item)
 	{
 		m_item = item;
 	}
 	
 	T m_item;
 }
 
 public class Tuple<T, TRest> : ITuple where TRest : ITuple
 {
 	public int Length
	{
		get
		{
			return 1 + m_rest.Length;
		}
	}
 	
 	public object this[int index]
 	{
 		get
 		{
 			if (index == 0)
 			{
 				return m_item;
 			}
 			else
 			{
 				return m_rest[index - 1];
 			}
 		}
 	}
 	
 	public Tuple(T item, TRest rest)
 	{
 		m_item = item;
 		m_rest = rest;
 	}
 	
 	T m_item;
 	TRest m_rest;
 }
 
 public static class Tuple
 {
 	public static Tuple<T> Create<T>(T item)
 	{
 		return new Tuple<T>(item);
 	}
 	
 	public static Tuple<T1, Tuple<T2>> Create<T1, T2>(T1 item1, T2 item2)
 	{
 		return new Tuple<T1, Tuple<T2>>(item1, new Tuple<T2>(item2));
 	}
 	
 	public static Tuple<T1, Tuple<T2, Tuple<T3>>> Create<T1, T2, T3>(T1 item1, T2 item2, T3 item3)
 	{
 		return new Tuple<T1, Tuple<T2, Tuple<T3>>>(item1, new Tuple<T2, Tuple<T3>>(item2, new Tuple<T3>(item3)));
 	}
 	
 	public static Tuple<T1, Tuple<T2, Tuple<T3, Tuple<T4>>>> Create<T1, T2, T3, T4>(T1 item1, T2 item2, T3 item3, T4 item4)
 	{
 		return new Tuple<T1, Tuple<T2, Tuple<T3, Tuple<T4>>>>(item1, new Tuple<T2, Tuple<T3, Tuple<T4>>>(item2, new Tuple<T3, Tuple<T4>>(item3, new Tuple<T4>(item4))));
 	}
 	
 	// more Create interfaces here ...
 }