using System;

public delegate V Mapper<T,V> (T item);

public interface ITree<T>
{
	void Map<V> (Mapper<T,V> mapper);
}

public class Tree<T> : ITree<T>
{
	T item;

	public Tree (T item)
	{
		this.item = item;
	}

	public void Map<V> (Mapper<T,V> mapper)
	{
		V new_item = mapper (item);
	}
}

class X
{
	private string themap (int i)
	{
		return String.Format ("AA {0,4} BB", i);
	}

	void Test ()
	{
		Tree<int> tree = new Tree<int> (3);
		tree.Map (new Mapper<int,string> (themap));
	}

	static void Main ()
	{
		X x = new X ();
		x.Test ();
	}
}
