Astring_char
val err_byte : int -> string
type t = char
val unsafe_of_byte : int -> char
val of_byte : int -> char
val of_int : int -> char option
val to_int : char -> int
val hash : 'a -> int
val equal : t -> t -> bool
val compare : t -> t -> int
module Ascii : sig ... end
val pp : Format.formatter -> char -> unit
val dump : Format.formatter -> char -> unit