Barry Margolin  <barmar@alum.mit.edu> wrote:
+---------------
| Is there any way in which a wild pathname could
| conceivably be the truename of a specific file?
+---------------

Try this with your favorite shell & CL:

    $ echo "harmless, really" >badnamesortof
    $ echo "bad file, BAD!" >badname\*
    $ ls -l badname*
    -rw-r--r--  1 rpw3  rpw3  15 Feb 24 02:30 badname*
    -rw-r--r--  1 rpw3  rpw3  17 Feb 24 02:36 badnamesortof
    $ cmu
    cmu> (pathname "badname*")

    #p"badname*"
    cmu> (describe *)

    #p"badname*" is a structure of type PATHNAME.
    HOST: #<COMMON-LISP::UNIX-HOST>.
    DEVICE: NIL.
    DIRECTORY: NIL.
    NAME: #<COMMON-LISP::PATTERN "badname" :MULTI-CHAR-WILD>.
    TYPE: NIL.
    VERSION: :NEWEST.
    cmu> (directory **)

    (#p"/u/rpw3/badname\\*" #p"/u/rpw3/badnamesortof")
    cmu> (directory (car *))

    (#p"/u/rpw3/badname\\*")
    cmu> (truename (car *))

    #p"/u/rpw3/badname\\*"
    cmu> (with-open-file (s *)
	   (loop for line = (read-line s nil nil)
		 while line do
	     (format t "~a~%" line)))
    bad file, BAD!
    NIL
    cmu> (describe **)

    #p"/u/rpw3/badname\\*" is a structure of type PATHNAME.
    HOST: #<COMMON-LISP::UNIX-HOST>.
    DEVICE: NIL.
    DIRECTORY: (:ABSOLUTE "u" "rpw3").
    NAME: "badname*".
    TYPE: NIL.
    VERSION: :NEWEST.
    cmu> 

Hmmmm... That's not actually a "wild pathname", is it?

Though note that the *printed* representations of both
the "real" wild pathname and the individual file were the
same, and if one were particularly sloppy in subsequent
manipulations one might get back to a wild pathname by
mistake, e.g.:

    cmu> (pathname (pathname-name ***))

    #p"badname*"
    cmu> (describe *)

    #p"badname*" is a structure of type PATHNAME.
    HOST: #<COMMON-LISP::UNIX-HOST>.
    DEVICE: NIL.
    DIRECTORY: NIL.
    NAME: #<COMMON-LISP::PATTERN "badname" :MULTI-CHAR-WILD>.
    TYPE: NIL.
    VERSION: :NEWEST.
    cmu> 

Oops.


-Rob

-----
Rob Warnock			<rpw3@rpw3.org>
627 26th Avenue			<URL:http://rpw3.org/>
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