(* OCaml comments *)

(* 12345 *)
(* 67890 " 12345 " *)
   (* 67890 (* 12345 '
               67890 (** 12345
              '       *)*)*)
(**)

let a = "xxx\" (* xxx *)";;
let b = '\'';;

print_string(*67890*)"[ml] hello world\n";;
(* 12345 *)