[Gcl-devel] Re: probe-file on directories

[Camm Maguire]

Greetings!

Here is the best common lisp way I can see at the moment, requiring
windows portability and the like:

(defun pathname-pop-slash (pn)
  (let ((pn (pathname pn)))
        (if (or (pathname-name pn) (pathname-type pn)) pn 
          (merge-pathnames 
           (make-pathname :directory (butlast (pathname-directory pn))) 
           (merge-pathnames (pathname (car (last (pathname-directory pn)))) 
pn)))))

(defun directory-exists-p (pn) 
  (let ((pn (pathname-pop-slash pn)))
    (and (not (probe-file pn)) (member pn (directory pn) :test 'equal) t)))

This is more direct, but of course gcl specific:

(defun directory-exists-p (pn) 
        (unless (fboundp 'si::stat) (error "No stat"));Can't remember
                                                      ; exactly when
                                                      ; this was added
        (eq :directory (car (si::stat (namestring pn)))))

Please let me know if problems persist.

Take care,

Matt Kaufmann <address@hidden> writes:

> Hi, Camm --
> 
> Actually, what I want to be able to do is to test whether a directory
> exists, without error.  Is there a way to do that in 64-bit linux GCL
> 2.6.7?
> 
> Thanks --
> -- Matt
>    Cc: address@hidden, address@hidden
>    From: Camm Maguire <address@hidden>
>    Date: 23 Jan 2007 17:43:30 -0500
>    X-SpamAssassin-Status: No, hits=-2.5 required=5.0
>    X-UTCS-Spam-Status: No, hits=-250 required=200
> 
>    Greetings!
> 
>    Yes, this has been an ansi change pushed into 2.6 to accomodate axiom,
>    mainly.   The spec at least appears to indicate that this function
>    should be specific to files, though I think Paul has decided that it
>    is vague enough not to force an error in his test suite.  In any case,
>    there appears to be no standard function (barring this reading) which
>    enables one to distinguish a file from a directory.  How then might
>    one write, for example, a little web server on a socket which will
>    copy files across, but not attempt to open directories?  It was
>    decided to therefore use probe-file to indicate a true file, and
>    the output of 'directory and the various pathname functions to
>    indicate directories.  clisp does similar, if memory serves.
> 
>    truename won't work if you need to avoid error on missing pathnames,
>    but will otherwise.
> 
>    In general, it was felt at the time that the spec was unsatisfactory
>    on this point, so we have also supplied a gcl specific function,
>    (si::stat ...), which distinguishes files from directories, gives the
>    size, and the inode, at present.
> 
>    Please let me know if any of this is a problem for you.
> 
>    Take care,
> 
>    Matt Kaufmann <address@hidden> writes:
> 
>    > Hi --
>    > 
>    > I've always been able to use probe-file to see if a directory exists,
>    > but that doesn't seem to be working on a 64-bit linux machine, in GCL
>    > 2.6.7 CLtL1 or (a version of) 2.7.0 ANSI.  Any suggestions?  The
>    > following log shows that probe-file is returning nil for a directory
>    > that clearly exists.
>    > 
>    >   lhug-1:/projects/acl2/devel> ~boyer/bin-override/5
>    >   GCL (GNU Common Lisp)  2.7.0 ANSI    Dec  5 2006 20:38:58
>    >   Source License: LGPL(gcl,gmp,pargcl), GPL(unexec,bfd,xgcl)
>    >   Binary License:  GPL due to GPL'ed components: (XGCL READLINE BFD 
> UNEXEC)
>    >   Modifications of this banner must retain notice of a compatible license
>    >   Dedicated to the memory of W. Schelter
>    > 
>    >   Use (help) to get some basic information on how to use GCL.
>    > 
>    >   Temporary directory for compiler files set to /tmp/
>    > 
>    >   >(probe-file "/projects/acl2/devel/books/")
>    > 
>    >   NIL
>    > 
>    >   >(probe-file "/projects/acl2/devel/books")
>    > 
>    >   NIL
>    > 
>    >   >(probe-file "/projects/acl2/devel/books/certify-numbers.lisp")
>    > 
>    >   #P"/v/filer3/v0q004/acl2/devel/books/certify-numbers.lisp"
>    > 
>    >   >
>    > 
>    > Thanks --
>    > -- Matt
>    > 
>    > 
>    > 
> 
>    -- 
>    Camm Maguire                                               address@hidden
>    ==========================================================================
>    "The earth is but one country, and mankind its citizens."  --  Baha'u'llah
> 
> 
> 

-- 
Camm Maguire                                            address@hidden
==========================================================================
"The earth is but one country, and mankind its citizens."  --  Baha'u'llah