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

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

#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

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

open System


(*
## The requirements

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

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