The simplest Future constructs available in C#. The first one is an Action that takes a Func that produces a value (the work) and an Action that consumes the result (the callback) as parameters. The second is a Func that takes a Func that produces a value as parameter (the work to do) and returns an Action that calls another Action, provided by …

Simplest C# Future

class Program
{
  static void Main(string[] args)
  {
    // first implementation with callback provided directly 
    Action<Func<int>, Action<int>> future =
      (work, callback) => ThreadPool.QueueUserWorkItem(_ => callback(work()));

    // example application (will print "Result: 3")
    future(() => 1 + 2, result => Console.WriteLine("Result: {0}", result));

    // second implementation with callback provided via currying
    Func<Func<int>, Action<Action<int>>> curriedFuture =
      work => callback => ThreadPool.QueueUserWorkItem(_ => callback(work()));

    // example application (will print "Result: 5")
    curriedFuture(() => 2 + 3)(result => Console.WriteLine("Result: {0}", result));

    // keep the app from closing before the callbacks have been called
    Console.ReadLine();
  }
}