クソコードであると表明するだけのコンピュテーション式。これ自体がクソコード

kuso.fsx

open System

type KusoBuilder() =
    member __.Bind(x, f) = f x
    member __.Return(x) = x
    member __.ReturnFrom(x) = x
    member __.Using(x: #IDisposable, f) = try f x finally if x |> box |> isNull |> not then x.Dispose()
    member __.Zero() = ()
    member __.Combine(_, f) = f()
    member __.TryWith(f, g) = try f() with e -> g e
    member __.TryFinally(f, g) = try f() finally g()
    member __.For(xs, f) = for x in xs do f x
    member __.While(c, f) = while c() do f()
    member __.Delay(f) = f
    member __.Run(f) = f()

let kuso = KusoBuilder()

let kusoExample() =
    kuso {
        // let! を使うことで特にここがクソ！とアピールできるがそれ以外の機能はない
        let! kuso1 = 1 + 1
        use kuso2 = { new IDisposable with member __.Dispose() = printfn "disposed" }
        // do! で特にクソな部分な上に副作用まで発生させることを表明できる
        do!  printfn "kuso!"
        for x in 1 .. 5 do
            printfn "x : %d" x
        let mutable y = 5
        while y > 0 do
            printfn "y : %d" y
            y <- y - 1
        return kuso1 + 2
    }