play a game of "Guess or Die", with aggressive save-scumming

quicksave.eff

effect QuickSave: int option
effect QuickLoad: int -> empty

let quicksave () = perform QuickSave
let quickload n = absurd (perform (QuickLoad n))

let quicksaving = handler
  | effect QuickSave k ->
      let rec quickloading () = handler
        | effect (QuickLoad n) _ ->
            with quickloading () handle
            continue k (Some n)
      in
      with quickloading () handle
      continue k None

type outcome =
  | Success
  | Death

let guess_or_die () =
  let r = perform (RandomInt 10) in
  fun n -> if n = r then Success else Death;;

let game = guess_or_die ();;

let play game =
  let n = match quicksave () with
    | None -> 0
    | Some n -> n
  in
  match game n with
    | Success -> n
    | Death -> quickload (n + 1)
;;

with quicksaving handle
play game