(* "Single-threaded" threads *)

module AThread : sig
  type thread qualifier A

  val fork  : (unit -o unit) -> thread
  val kill  : thread -> unit
  val delay : int -> unit
  val print : thread -> thread
end = struct
  open Thread
  let fork = (fork :> (unit -o unit) -> thread)
  let print (th: thread) = print th; th
end