C# expression of model Toyl program ToylModel20130322

ToylModel20130322.cs

using System;

namespace ToylModel20130322
{
	public delegate TReturn ToylFunc<TReturn>();
	public delegate TReturn ToylFunc<T1, TReturn>(ISignature<T1> p1);
	public delegate TReturn ToylFunc<T1, T2, TReturn>(ISignature<T1> p1, ISignature<T2> p2);

	public interface ISignature<T> {
		T Value();
	}

	public class Constant<T> : ISignature<T> {
		private T _value;
		public Constant(T value) {
			this._value = value;
		}
		public T Value() {
			return this._value;
		}
	}

	public class CurryFactory<T1, T2, TReturn> {
		private ISignature<T1> _p1;
		private ToylFunc<T1, T2, TReturn> _currier;

		private CurryFactory(ToylFunc<T1, T2, TReturn> currier, ISignature<T1> p1) {
			this._p1 = p1;
			this._currier = currier;
		}

		public static ToylFunc<T2, TReturn> Curry(ToylFunc<T1, T2, TReturn> currier, ISignature<T1> p1) {
			CurryFactory<T1, T2, TReturn> factory = new CurryFactory<T1, T2, TReturn> (currier, p1);
			return factory.CurriedMethod;
		}

		public TReturn CurriedMethod(ISignature<T2> p2) {
			return this._currier (this._p1, p2);
		}
	}

	public class ToylModel20130322 {
		public int AddAndMultiply(ISignature<int> x, ISignature<int> y) {
			if (x.Value () < 0) {
				throw new Exception("x must not be less than zero");
			} else {
				return (y.Value () + x.Value ()) * x.Value ();
			}
		}

		public ISignature<int> C13 = new Constant<int>(13);

		public ToylFunc<int, int> AddCAndMultiplyByC;

		public static class HigherOrder<T> {
			public static T ApplyTwice(ISignature<ToylFunc<T, T>> f, ISignature<T> v) {
				return f.Value ()(new Constant<T>(f.Value () (v)));
			}
		}
		
		ToylFunc<ToylFunc<int, int>, int, int> ApplyTwice = HigherOrder<int>.ApplyTwice;

		public int TestFunction() {
			//   ApplyTwice(AddCAndMultiplyByC, 72)
			// = AddCAndMultiplyByC(AddCAndMultiplyByC(72))
			// = AddCAndMultiplyByC((72 + 13) * 13)
			// = AddCAndMultiplyByC(1105)
			// = (1105 + 13) * 13
			// = 14534
			return ApplyTwice
				(
					new Constant<ToylFunc<int, int>>(AddCAndMultiplyByC),
					new Constant<int>(72)
				);
		}

		public ToylModel20130322() {
			this.AddCAndMultiplyByC = CurryFactory<int, int, int>.Curry (this.AddAndMultiply, this.C13);
		}
	}
}