sig
type t =
[ `A of OpamJson.t list
| `Bool of bool
| `Float of float
| `Null
| `O of (string * OpamJson.t) list
| `String of string ]
val to_string : OpamJson.t -> string
val add : OpamJson.t -> unit
val output : unit -> unit
val set_output : (string -> unit) -> unit
val verbose : unit -> bool
end