type 'a t = 'a Extend.entry
val create : string -> 'a tval parse : 'a t -> Parsable.t -> 'aval print : Stdlib.Format.formatter -> 'a t -> unitval of_parser : string -> (Tok.t Stdlib.Stream.t -> 'a) -> 'a tval parse_token_stream : 'a t -> Tok.t Stdlib.Stream.t -> 'aval name : 'a t -> string