gistfile1.txt

    (* Type of data record *)
    type rectype = CharArray | Number

    (* My type *)
    type _ mytype =
      | String : string mytype
      | Bool : bool mytype
      | Int : int mytype

    (* Check that data record type is compatible with my type *)
    let validate (type a) (ty : a mytype) (v : rectype) =
      match (ty, v) with
      | (String, CharArray)
      | (Bool, Number)
      | (Int, Number) -> true
      | _ -> false