why doesn't r5rs define delete-file ?
> Brian> Since the effect of output to file procedures is "unspecified" when
> Brian> the file exists. In theory this is a big portability gap, because
> Brian> there is no "file-exists?" procedure and no "file-delete" procedure
> Brian> defined. So now you have to depend on non-standard extensions.
> Brian> So R5RS leaves you stuck with non-portable code.
> Brian> I guess that maybe there is an SRFI lurking here somewhere,
> Brian> isn't there ?
> Not yet. It's somewhat harder to do right than it may look at first
Now that's one way of putting it.
I have recently been suffering with CL's logical pathnames, which in
theory are a way of writing portable code dealing with different
filesystems, whether they be networked or local, and independent of
the OS on which the system is running.
This is fine in theory; in practice, however, each lisp implementation
interprets the standard slightly differently; each filesystem has
slightly broken semantice, meaning that this laudable aim of limited
portability (the actions you can take are necessarily the intersection
of supported actions) isn't even remotely achieved.
It's probably worth taking a look at the CL specification in this area
before sitting down and specifying anything else.
 Bugs have begun to be fixed in the implementations, though...
Jesus College, Cambridge, CB5 8BL +44 1223 510 299
http://www-jcsu.jesus.cam.ac.uk/~csr21/ (defun pling-dollar
(str schar arg) (first (last +))) (make-dispatch-macro-character #\! t)
(set-dispatch-macro-character #\! #\$ #'pling-dollar)