gusty

let trampoline f c n =
    let rec loop = function
    | Choice1Of2 x -> x
    | Choice2Of2 x -> loop (f x)
    loop (Choice2Of2 (c,n))

// Test
let factorial n = 
    let rec factorialT (current, n) =
        if n = bigint 0 then Choice1Of2 current

gusty

// Unfortunatelly it stopped working in F# 4.1 after this PR https://github.com/Microsoft/visualfsharp/pull/1650
// Will ask to revert it

type FoldArgs<'t> = FoldArgs of ('t -> 't -> 't)

let inline foldArgs f (x:'t) (y:'t) :'rest = (FoldArgs f $ Unchecked.defaultof<'rest>) x y

type FoldArgs<'t> with
    static member inline ($) (FoldArgs f, _:'t-> 'rest) = fun (a:'t) -> f a >> foldArgs f
    static member        ($) (FoldArgs f, _:'t        ) = f

gusty

(* ===================================
Code from my series of posts "Six approaches to dependency injection"
=================================== *)

open System


(*
## The requirements

gusty

#r "nuget: FSharpPlus,1.2"

open FSharpPlus
open FSharpPlus.Math.Generic

type Ratio =
    struct
        val Numerator   : bigint
        val Denominator : bigint
        new (numerator: bigint, denominator: bigint) = {Numerator = numerator; Denominator = denominator}

gusty

open System.Collections.Concurrent

type T = T with static member getOrAdd (cd:ConcurrentDictionary<_,'t>) (f:_ -> _) k = cd.GetOrAdd (k, f)

let inline memoize (f:'``(T1 -> T2 -> ... -> Tn)``): '``(T1 -> T2 -> ... -> Tn)`` = (T $ Unchecked.defaultof<'``(T1 -> T2 -> ... -> Tn)``>) f

type T with     
    static member        ($) (_:obj,  _: 'a -> 'b) = T.getOrAdd (ConcurrentDictionary ())
    static member inline ($) (T, _:'t -> 'a -> 'b) = T.getOrAdd (ConcurrentDictionary ()) << (<<) memoize
    

gusty

// Based on http://nut-cracker.azurewebsites.net/blog/2011/11/07/functions-for-n-tuples/

// Warning: This script has long compile times
// but as from F# 4.1 will work fine
// due to this fix: https://github.com/Microsoft/visualfsharp/pull/1682 in the compiler

open System
type Infinite<'a> = Infinite of 'a
    
module TupleInternalValues =

gusty

+--------------------+--------------------+-------------------------+--------------------+
|Operation           | F#+ / F#           |F#+ Haskell Compatibility|Haskell             |
+====================+====================+=========================+====================+
|List.append         | @                  |                         | ++                 |
+--------------------+--------------------+-------------------------+--------------------+
|Function composition| f << g             | f . (g)                 | f . g              |
+--------------------+--------------------+-------------------------+--------------------+
|                    | <|                 | $                       | $                  |
+--------------------+--------------------+-------------------------+--------------------+

gusty

#nowarn "0042"
let inline retype (x: 'T) : 'U = (# "" x: 'U #)

open System
type Curry =

    static member inline Invoke f =
        let inline call_2 (a: ^a, b: ^b) = ((^a or ^b) : (static member Curry: _*_ -> _) b, a)
        call_2 (Unchecked.defaultof<Curry>, Unchecked.defaultof<'t>) (f: 't -> 'r) : 'args

gusty

#load @".paket\load\net452\FSharpPlus.fsx"

open FSharpPlus
open System

[<AutoOpen>]
module SideEffects =
    let private r = Random()
    let printLn text = async { printfn "%s" text }
    let readLn() = async { return Console.ReadLine() }

gusty

type A = class end
type B = class inherit A end
type C = class inherit B end
type D = class inherit C end

type IsNull = 
    inherit D
    static member inline ($) (_:A  , x  :'a when 'a : not struct) = System.Object.ReferenceEquals(x, null)
    static member inline ($) (_:B  , x  :'a when 'a : null      ) = match x with null -> true | _ -> false
    static member inline ($) (_:C  , _:D) = false