warned.ml

include (struct
  type 'a t = 'a * string list

  exception FatalWarning of string list

  let to_exn: 'a t -> 'a = function
    | value, [] -> value
    | value, warnings -> raise (FatalWarning warnings)

  let map f (value, warnings) = f value, warnings

  let of_option replacement warning = function
    | Some value -> value, []
    | None -> replacement, [warning]

  let ok value = value, []
  let warned value warning = value, [warning]

  let create ?(warnings=[]) value = value, warnings
end: sig
  type 'a t

  exception FatalWarning of string list

  val to_exn: 'a t -> 'a
  val map: ('a -> 'b) -> 'a t -> 'b t
  val of_option: 'a -> string -> 'a option -> 'a t
  val ok: 'a -> 'a t
  val warned: 'a -> string -> 'a t
  val create: ?warnings:string list -> 'a -> 'a t
end)