Unix pathnames are always parsed with a unix-host object as the host andnil 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.
(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 search-lists) is starts :absolute, others start with:relative. The .. directory is parsed as :up; there is no namestring for :back: