val level : int Stdlib.ref
val dprintf : int -> ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a
val eprintf : ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a
val raw_dprintf : int -> ('a, Stdlib.Format.formatter, unit) Stdlib.format -> 'a
val classic_display : bool Stdlib.ref
val event : ?pretend:bool -> string -> string -> Tags.t -> unit
val display : (Stdlib.out_channel -> unit) -> unit