https://twitter.com/__josejuan__/status/449623376479285248

gistfile1.cs

using System;
using System.Collections.Generic;
using System.Linq;

static class Extensions {
    public static Func<A, IEnumerable<C>> Kleisli<A,B,C>(this Func<A, IEnumerable<B>> f, Func<B, IEnumerable<C>> g) {
        return a => from b in f(a) from c in g(b) select c;
    }
}

class Program {
    static void Main(string[] args) {
        Func<int, IEnumerable<string>> f = i => Enumerable.Range(0, i).Select(x => x.ToString());
        Func<string, IEnumerable<string>> g = s => s.Split(',');
        Func<string, IEnumerable<int>> digits = s => new[] { s.IndexOf("0") };

        // verbose kleisli composition with LINQ:
        {
            var r =
                from a in f(20)
                from b in g(a)
                from c in digits(b)
                select c;

        }

        // point-free kleisli composition
        {
            var r = f.Kleisli(g).Kleisli(digits)(20);

        }
    }
}