//https://medium.com/@dimpapadim3/deriving-continuation-monad-from-callbacks-23d74e8331d0

using System;

​

namespace Monads.ContinuationMonad

{

    public class Demo

    {

        public static void Main()

        {

            Func<int, int> square = x => x * x;

            var d =

                from func in square.ToContinuation<Func<int, int>, int>()

                from y in 3.ToContinuation<int, int>()

                select func(y);

​

            //untill here there was no execution of the squaring fucntion. This is the point of Continuation monad.

            //now we can materialize the continuation and collapse the continuation in a single value

            var result = d(x => x);

            Console.WriteLine(result);

        }

    }

    public delegate T Cont<U, T>(Func<U, T> f);

    public static class Extensions

    {

        public static Cont<U, T> ToContinuation<U, T>(this U x)

        {

            return (callback) => callback(x);

        }

​

        public static Cont<V, Answer> SelectMany<T, U, V, Answer>(this Cont<T, Answer> m, Func<T, Cont<U, Answer>> k, Func<T, U, V> selector)

        {

            return (Func<V, Answer> c) => m(t => k(t)(y => c(selector(t, y))));

        }

    }

​

​

}