-- Ex 8.1 --------------------------------------------------------------------

let optexp =
  (token (fun (`e`|`E`) -> true | _ -> false)
   andalso optsign
   andalso digits)
  orelse empty
;;

-- Ex 8.2 --------------------------------------------------------------------

let optfrac =
  (char `.` andalso (zero_or_more digits)) gives (fun (dot, cs) -> dot::cs)
  orelse (empty [])
;;

let optexp =
  ((char `e` orelse char `E`)
   andalso optsign
   andalso digits) gives (fun ((e,s),ds) -> e@s@ds)
  orelse (empty [])
;;

-- Ex 8.3 --------------------------------------------------------------------

let rec paren = function
    [< ' `(`; paren _; ' `)` >] -> ()
  | [< >] -> ();;
;;

-- Ex 8.4 --------------------------------------------------------------------

=> FIXME