2.13.1 Unix Pathnames

 

Unix pathnames are always parsed with a unix-host object as the host and nil as the device. The last two dots (.) in the namestring mark the type and version, however if the first character is a dot, it is considered part of the name. If the last character is a dot, then the pathname has the empty-string as its type. The type defaults to nil and the version defaults to :newest.

(defun parse (x)
  (values (pathname-name x) (pathname-type x) (pathname-version x)))

(parse "foo")  "foo", NIL, :NEWEST
(parse "foo.bar")  "foo", "bar", :NEWEST
(parse ".foo")  ".foo", NIL, :NEWEST
(parse ".foo.bar")  ".foo", "bar", :NEWEST
(parse "..")  ".", "", :NEWEST
(parse "foo.")  "foo", "", :NEWEST
(parse "foo.bar.1")  "foo", "bar", 1
(parse "foo.bar.baz")  "foo.bar", "baz", :NEWEST

The directory of pathnames beginning with a slash (or a search-list, see section 2.13.4) is starts :absolute, others start with :relative. The .. directory is parsed as :up; there is no namestring for :back:

(pathname-directory "/usr/foo/bar.baz")  (:ABSOLUTE "usr" "foo")
(pathname-directory "../foo/bar.baz")  (:RELATIVE :UP "foo")