let xnx chars = let ox = "[" ^ chars ^ "]*" and nx = "[^" ^ chars ^ "]" in ox ^ "(" ^ nx ^ "(" ^ ox ^ nx ^ ")*)" ^ ox let xonx chars = let ox = "[" ^ chars ^ "]*" and nx = "[^" ^ chars ^ "]" in ox ^ "((" ^ nx ^ "(.*" ^ nx ^ ")*)*)" ^ ox let wnw () = xnx " \t\n" let wonw () = xonx " \t\n"