as2_vocab/common.ml

   1 module D = Decoders_ezjsonm.Decode
   2
   3 let rfc3339 =
   4   let open D in
   5   let* time = string in
   6   match time |> Ptime.of_rfc3339 |> Ptime.rfc3339_error_to_msg with
   7   | Ok (t, _, _) -> succeed t
   8   | Error `Msg err -> fail err
   9
  10 let singleton_or_list dec =
  11   D.(one_of ["singleton", (dec >|= fun v -> [v]);
  12              "list", list dec;
  13              "null", null >|= fun () -> []])
  14
  15 let lossy_list_of dec =
  16   let open D in
  17   list (one_of ["known", (dec >|= fun v -> `Value v)(*; "unknown", value >|= fun v -> `Raw v*)])
  18
  19
  20 let constant ?msg target =
  21   let open D in
  22   let* str = string in
  23   if String.equal str target
  24   then succeed ()
  25   else match msg with
  26     | None -> fail (Printf.sprintf "expected %s received %s" target str)
  27     | Some msg -> fail (Printf.sprintf msg str)
  28
  29 let field_or_default field' decoder default =
  30   let open D in
  31   let+ field = field_opt field' decoder in
  32   Option.value ~default field
  33
  34 let list_ignoring_unknown ty =
  35   let open D in
  36   list (maybe ty) >|= fun v -> List.filter_map Fun.id v
  37
  38 let items obj =
  39   let open D in
  40   one_of [
  41     ("ordered items",
  42      let* items = field "orderedItems" (list obj) in
  43      succeed (true, items));
  44     "items",
  45     let* items = field "items" (list obj) in
  46     succeed (false, items)
  47   ]
  48
  49 let items_opt obj =
  50   let open D in
  51   maybe (items obj)