Pipelines and fluent interfaces

1-Pipelines-FSharp-example.fs

//already defined in F# base library, but I wanted to show how simple it is
let (|>) a f = f a

let latestRequest = 
    user
      |> login
      |> clickMenu "Forms"
      |> waitPageLoad
      |> openFilter ["Communication"; "Request"]
      |> results
      |> Seq.head

2-Pipelines-CSharp-substitution.cs

class Program {
    static void Main(string[] args) {
        var latestRequest = 
            //.Take() is completely unnecessary, but it may make it look more "natural" (or not)
            User.Take() 
                .Then(Login)
                .Then(ClickMenu, "Forms")
                .Then(WaitForPageLoad)
                .Then(OpenFilter, new[] { "Communication", "Request" })
                .Then(GetResults)
                .First();
        }
    }

public static class Pipeline {
    //an identity function, just syntaxic sugar for making pipelines more "natural"
    public static A Take<A>(this A self) { return self; }

    public static B Then<A, B>(this A self, Func<A, B> selector) {
        return selector(self);
    }

    public static B Then<A, P1, B>(this A self, Func<P1, A, B> selector, P1 p1) {
        return selector(p1, self);
    }

    public static B Then<A, P1, P2, B>(this A self, Func<P1, P2, A, B> selector, P1 p1, P2 p2) {
        return selector(p1, p2, self);
    }

    public static B Then<A, P1, P2, P3, B>(this A self, Func<P1, P2, P3, A, B> selector, P1 p1, P2 p2, P3 p3) {
        return selector(p1, p2, p3, self);
    }
}