functor (J : Json_converter) ->
sig
type a = J.b
val t : a t
val write : Buffer.t -> a -> unit
val read : Deriving_Json_lexer.lexbuf -> a
val to_string : a -> string
val from_string : string -> a
val match_variant : [ `Cst of int | `NCst of int ] -> bool
val read_variant :
Deriving_Json_lexer.lexbuf -> [ `Cst of int | `NCst of int ] -> a
end