module type TOKEN =
sig
        type t
        val to_string : t -> string
end

module Make_M (Token : TOKEN)  =
struct
        type t = { x : Token.t }
        let create (value : Token.t) = { x = value }
        let f (a : t) =
                print_endline (Token.to_string a.x)
end


module IntToken =
struct
        type t = int
        let to_string = string_of_int
end


let () =
        let module M = Make_M (IntToken) in
        let z = M.create 5 in ()