using System;

using static Utils;

public class Program

{

    public static void Main()

    {

        Func<int,int,int,int> distance = (x, y, z) => x + y + z;

        int x = Get(distance).From(1).To(2).On(3);

        Console.WriteLine("Get(distance).From(1).To(2).On(3) => {0}", x);

    }

}

​

// Kind of library code

public static class Utils

{

    public static Get2<T1, T2, T3, T4> Get<T1, T2, T3, T4>(Func<T1, T2, T3, T4> f)

    {

        return new Get2<T1, T2, T3, T4>(f);

    }

public class Get2<T1, T2, T3, T4>

{

    private Func<T1, T2, T3, T4> _f;

​

    internal Get2(Func<T1, T2, T3, T4> f)

    {

        _f = f;

    }

    public B1 From(T1 x)

    {

         return new B1(this, x);

    }

    public class B1

    {

        internal Get2<T1, T2, T3, T4> _b;

        internal T1 _x;

        public B1(Get2<T1, T2, T3, T4> b, T1 x)

        {

            _b = b;

            _x = x;

        }

        public B2 To(T2 y)

        {

            return new B2(this, y);

        }

    }

​

    public class B2

    {

        internal B1 _b;

        internal T2 _y;

        public B2(B1 b, T2 y)

        {

            _b = b;

            _y = y;

        }

        public B3 On(T3 z)

        {

            return new B3(this, z);

        }

    }

​

    public class B3

    {

        internal B2 _b;

        internal T3 _z;

        public B3(B2 b, T3 z)

        {

            _b = b;

            _z = z;

        }

        public static implicit operator T4(B3 b3)

        {

            return b3._b._b._b._f(b3._b._b._x, b3._b._y, b3._z);

        }

    }

}

}