From ... Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newsfeed.esat.net!nslave.kpnqwest.net!nloc1.kpnqwest.net!nloc.kpnqwest.net!nmaster.kpnqwest.net!nreader2.kpnqwest.net.POSTED!not-for-mail Newsgroups: comp.lang.lisp Subject: Re: Must MAPCAR substitute NIL for nothing? References: Mail-Copies-To: never From: Erik Naggum Message-ID: <3215360490307858@naggum.net> Organization: Naggum Software, Oslo, Norway Lines: 18 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.1 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 21 Nov 2001 19:41:31 GMT X-Complaints-To: newsmaster@KPNQwest.no X-Trace: nreader2.kpnqwest.net 1006371691 193.71.66.49 (Wed, 21 Nov 2001 20:41:31 MET) NNTP-Posting-Date: Wed, 21 Nov 2001 20:41:31 MET Xref: archiver1.google.com comp.lang.lisp:20626 * Dr. Edmund Weitz | have I missed something more basic than the definition of MAPCAR in | the standard that forces CL to always return (1 NIL 3) in this case? Yes. The primary value of (values) is nil. | I think it could be convenient to be able to suppress values in such a | way but maybe you can convince me that I haven't thought deeply enough | about it. Use mapcan and return lists of varying lengths. /// -- Norway is now run by a priest from the fundamentalist Christian People's Party, the fifth largest party representing one eighth of the electorate. -- Carrying a Swiss Army pocket knife in Oslo, Norway, is a criminal offense.