gadts

type 'a nums = Int : int nums | Float : float nums

let random_array =
  let did_init = ref false in
  if not !did_init then (Random.self_init (); did_init := true);
  fun (type t) n (num_t : t nums) ->
  match num_t with
  | Int -> (Array.init n (fun _ -> Random.int max_int) : t array)
  | Float -> (Array.init n (fun _ -> Random.float max_float) : t array)