module ID : sig
  (** [t] is a ID within a range *)
  type t

  val create : int -> t
  (** [create num] is an ID [t] *)

  val incr : t -> t
  (** [incr id] is the next [id] in the sequence *)

  val to_string : t -> string
  (** [to_string id] is an string representation of [id] *)

  val pp : t -> string
  (** [pp id] is a pretty string representing [id] *)
end