let () =
  match Sys.argv with
  | [| _; ocaml_version; fname |] ->
      let is_current =
        Filename.basename fname = Printf.sprintf "ast_%s.ml" ocaml_version
      in
      let ic = open_in_bin fname in
      Printf.printf "# 1 %S\n" fname;
      Pp_rewrite.rewrite is_current ocaml_version (Lexing.from_channel ic)
  | _ ->
      Printf.eprintf "%s: <ocaml-version> <file-name>\n" Sys.executable_name;
      exit 2