+let get_opt () : opt =
+ let assert_ test x msg =
+ if not (test x) then begin
+ eprintf "%s\n%!" msg;
+ exit 1
+ end
+ in
+ let assert_file_exists path =
+ assert_ Sys.file_exists path (sprintf "File does not exist: %S" path)
+ in
+ let assert_file_is_dir path =
+ assert_ Sys.is_directory path (sprintf "File is not a directory: %S" path)
+ in
+ let input = ref Stdin in
+ let output = ref Stdout in
+ let ignore = ref None in
+ let spec =
+ [ ( "-out"
+ , Arg.String (fun path ->
+ assert_file_exists path;
+ assert_file_is_dir path;
+ output := Directory path
+ )
+ , " Output to this directory instead of stdout."
+ )
+ ; ( "-ignore"
+ , Arg.String (fun regexp -> ignore := Some (Str.regexp regexp))
+ , " Ignore file paths which match this regexp pattern (see Str module)."
+ )
+ ]
+ in