From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Thorsten Jolitz Newsgroups: gmane.emacs.help Subject: Re: How to make (format "%S" ...) print nothing? Date: Sat, 12 Jul 2014 17:44:11 +0200 Message-ID: <87fvi6lgz8.fsf@gmail.com> References: <87sim6luw2.fsf@gmail.com> <87ion2y7hm.fsf@motoko.kusanagi> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1405179897 4787 80.91.229.3 (12 Jul 2014 15:44:57 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 12 Jul 2014 15:44:57 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Jul 12 17:44:50 2014 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1X5zTl-0004AT-Ep for geh-help-gnu-emacs@m.gmane.org; Sat, 12 Jul 2014 17:44:49 +0200 Original-Received: from localhost ([::1]:49446 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X5zTk-0003Nq-Lo for geh-help-gnu-emacs@m.gmane.org; Sat, 12 Jul 2014 11:44:48 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51622) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X5zTU-0003ML-7i for help-gnu-emacs@gnu.org; Sat, 12 Jul 2014 11:44:38 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X5zTN-0007H9-HQ for help-gnu-emacs@gnu.org; Sat, 12 Jul 2014 11:44:32 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:40509) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X5zTN-0007Gd-B6 for help-gnu-emacs@gnu.org; Sat, 12 Jul 2014 11:44:25 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1X5zTL-0003hT-55 for help-gnu-emacs@gnu.org; Sat, 12 Jul 2014 17:44:23 +0200 Original-Received: from g231226016.adsl.alicedsl.de ([92.231.226.16]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 12 Jul 2014 17:44:23 +0200 Original-Received: from tjolitz by g231226016.adsl.alicedsl.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 12 Jul 2014 17:44:23 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 22 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: g231226016.adsl.alicedsl.de User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) Cancel-Lock: sha1:LpjqwXoSs5ctkT1f/z6GWqAWBy4= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:98660 Archived-At: W. Greenhouse writes: > Thorsten Jolitz writes: > >> Is there any way to use (format "%S"...) and have it print nothing >> when given an empty string, an empty list or nil (or something else)? > > No. The printed representation of the empty string is "", and the > printed representation of the list () or nil is nil, so (format "%S" ...) > will of course print something in these cases. Since you know what that > something is going to be, perhaps you could use split-string or a > similar text-mangling function to remove it. This was not really a problem I could not solve, its easy to work around it, I was just curious if there is some kind of 'hackers-trick', someTHING that could be given as arg that does not cause an error but has no printed representation. I guess not ... -- cheers, Thorsten