file-namestring directory-namestring host-namestring

(file-namestring pathname) -- (directory-namestring pathname) -- (host-namestring pathname)

The string-valued components of a namestring. file-namestring is the name-and-type part -- everything after the last /, or the whole namestring when there is none -- and directory-namestring is what comes before it, up to and including that /. The two are exact complements: concatenating them always gives namestring back. host-namestring is always "", because a rontolisp namestring carries no host syntax; pathname-host is the nil-answering spelling of the same absence, and Common Lisp requires a string here. All three accept either spelling of a pathname designator and signal on anything else, exactly like namestring.

A namestring that names a directory has no file half, and one without a / has no directory half:

The leading dot of a dotfile belongs to the name, the same rule pathname-name follows: (file-namestring "/a/.bashrc") is ".bashrc".

Backend support

All four backends -- one definition in rontolisp source, spliced into the program when it is referenced.