Monomorphic client values

Learning
1

I’m an Eliom beginner and get the error “The types of client values must be monomorphic from its usage or from its type annotation”. Here is my current example:

let%server add_item_form =
  let open Html.D in
  let inp = Raw.input ~a:[a_input_type `Text] () in
  let btn = Raw.button ~a:[a_class ["button"]] [txt "add"] in
  ignore
    [%client
      let open Html.D in
      let open Js_of_ocaml_lwt.Lwt_js_events in
      let inp = Html.To_dom.of_input ~%inp in
      (Lwt.async @@ fun() ->
        clicks (Html.To_dom.of_element ~%btn)
        (fun _ _ ->
          let v = inp##value |> Js_of_ocaml.Js.to_string in
          add_item {id="3";name=v;description=""};
          Lwt.return_unit):unit
      )];

  div [
    inp;btn
  ]

I assume, there is a problem with ~%inp and ~%btn. I wonder why I get this error, the code is similar like in the tutorials. What am I doing wrong?

2

You can fix this by annotating the client value:

  let _ : unit Lwt.t Eliom_client_value.t = [%client ...] in

Then you’ll need to use the valueattribute instead of a non-existing method:

          let v = inp##.value |> Js_of_ocaml.Js.to_string in

Hope it helps!

3

Thank you! It’s working now.