ANSI Common Lisp   19 Filenames   19.2 Pathnames   19.2.2 Interpreting Pathname Component Values

19.2.2.2 Special Pathname Component Values

19.2.2.2.1  NIL as a Component Value
19.2.2.2.2  :WILD as a Component Value
19.2.2.2.3  :UNSPECIFIC as a Component Value