`module Alphabet : sig ... end`
`type t`
`val add_reserved : string -> unit`
`val get_reserved : unit -> Stdlib.StringSet.t`
`val create : ?pretty:bool -> ?stable:bool -> Alphabet.t -> t`
`val reset : t -> unit`
`val to_string : t -> ?origin:int -> int -> string`
`val name : t -> int -> string -> unit`
`val get_name : t -> int -> string option`
`val propagate_name : t -> int -> int -> unit`
`val set_pretty : t -> bool -> unit`
`val set_stable : t -> bool -> unit`