let pp_formal (fmt:Format.formatter) (formal,lv) =
match formal with
| Fpref n ->
Format.fprintf fmt "%s%s" (String.make n '*') lv.lv_name
| Faref n ->
Format.fprintf fmt "%s%t"
lv.lv_name
(fun fmt -> for i=1 to n do Format.pp_print_string fmt "[]" done)