open Camlp4.PreCast

let _loc = Loc.mk "?"

let base base fields ty =

  let fields = List.fold_right (fun field acc ->

    let c = <:ctyp< $lid:field$ : $uid:field$.record >> in

    <:ctyp< $c$ ; $acc$ >>) fields <:ctyp< >>

  in

  <:module_binding< $uid:base$ :

    sig type record = {

        key : $ty$;

        $fields$

      } end = struct

        type record = {

        key : $ty$;

        $fields$

      } end

    >>

let _ =

  let b = base "b" ["f1"; "f2"] <:ctyp< int >> in

  Camlp4.PreCast.Printers.OCaml.print_implem

    <:str_item< module rec $b$ >>