> I picked the following trick from Gerd Stolpmann's findlib;
>
>    exception Toplevel_error of string;;
>
>    let toplevel_exec s =
>      let l = Lexing.from_string s in
>      let ph = !Toploop.parse_toplevel_phrase l in
>      let fmt = Format.make_formatter (fun _ _ _ -> ()) (fun _ -> ()) in
>        if not (Toploop.execute_phrase false fmt ph)
>        then raise (Toplevel_error s)
>    ;;

You'd probably want to have a different formatter at 'fmt = ...': This
formatter just suppresses arror messages which was good enough for my
purposes (extending the toplevel by some new directives :-) ).

Regards -- Markus