SteveGilham

let (>=>) f g
    = fun x -> (f x) >>= g;;

SteveGilham

let Join mm
    = mm >>= fun x -> x;;

SteveGilham

let rec Sequence l
    = match l with
      | [] -> Return []
      | h::t -> h >>= fun h1 -> (Sequence t) >>= fun t1 -> Return (h1::t1);;

SteveGilham

let ReturnList x = [x]
let FailList = []
let (>>=*) m f = List.concat (List.map f m);;

SteveGilham

let ReturnOption x = Some x
let FailOption = None
let (>>=?) m f = Option.bind f m;;

SteveGilham

type 'a io = IO of (unit -> 'a)
exception  IOFailure
let RunIO (IO f) = f();;

SteveGilham

let ReturnIO x = IO (fun () -> x)
let FailIO = IO (fun () -> raise IOFailure)
let (>>=) m f = IO (fun () -> RunIO(f(RunIO m)));;

SteveGilham

let GetC = IO (fun () -> System.Console.ReadKey(true).KeyChar)
let PutC  (c:char) = IO (fun () -> System.Console.Write c) ;;

SteveGilham

let EchoC = GetC >>= PutC;;

SteveGilham

let GetS length =
    let rec get chars count =
            if count > 0
            then GetC >>= fun c -> get (chars@[c]) (count – 1)
            else Return IO String(List.toArray chars)
    get [] length;;