val is_dir: string -> bool (** @return true if file is a directory *)
val writable_dir: string -> bool (** @return true if the directory is writable *)
val is_regular: string -> bool (** @return true if file is a regular file *)
val is_dir: string -> bool (** @return true if file is a directory *)
val writable_dir: string -> bool (** @return true if the directory is writable *)
val is_regular: string -> bool (** @return true if file is a regular file *)