[asdf-devel] Guard against (push "/foo/bar" asdf:*central-registry*)

[Richard M Kreuter]

Gary King writes:
> 
> (defun pathname-name+type (pathname)
>    "Returns a new pathname consisting of only the name and type from
> a non-wild pathname."
>    (make-pathname :name (pathname-name pathname)
>                   :type (pathname-type pathname)))

I believe that FILE-NAMESTRING is supposed to do roughly what you want
here.

> (defun ensure-directory-pathname (pathname)
>    (if (directory-pathname-p pathname)
>        pathname
>        (make-pathname
>         :directory `(,@(pathname-directory pathname)
> 		      ,(namestring (pathname-name+type pathname))))))

This loses the device component from PATHNAME, and is otherwise prone to
fail in case the host component of *DEFAULT-PATHNAME-DEFAULTS* differs
from the host component of PATHNAME.  How about

        (make-pathname :defaults pathname
                       :directory (append
                                   (pathname-directory pathname)
                                   (list (file-namestring pathname)))
                       :name nil :type nil :version nil)

?

Regards,
Richard