From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: How do you pre-evaluate a function passed to a macro? Date: Sat, 14 Nov 2009 03:18:25 -0500 Organization: UseNetServer.com Message-ID: References: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1258188159 10965 80.91.229.12 (14 Nov 2009 08:42:39 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 14 Nov 2009 08:42:39 +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 Nov 14 09:42:33 2009 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1N9EDH-0000Mr-Rz for geh-help-gnu-emacs@m.gmane.org; Sat, 14 Nov 2009 09:42:32 +0100 Original-Received: from localhost ([127.0.0.1]:49293 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1N9EDH-0004ro-BZ for geh-help-gnu-emacs@m.gmane.org; Sat, 14 Nov 2009 03:42:31 -0500 Original-Path: news.stanford.edu!usenet.stanford.edu!news.glorb.com!news2.glorb.com!npeer01.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post02.iad.highwinds-media.com!TEKSAVVY.COM-a2kHrUvQQWlmc!not-for-mail Original-Newsgroups: gnu.emacs.help User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) Cancel-Lock: sha1:9iS8nE5nWA/Hi7Bn3OTUHl/0srg= Original-X-Complaints-To: abuse@usenetserver.com Original-Lines: 17 Original-X-Trace: 67ffd4afe67d1e9af09f106264 Original-Xref: news.stanford.edu gnu.emacs.help:174655 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:69724 Archived-At: > I'm calling a function, wanting to pass nil instead of the empty string > when the string argument is zero length. But the function is defined as > a macro, so the argument gets passed in unevaluated, which fails. > How do I force evaluation of the argument before it is passed in? > --8<---------------cut here---------------start------------->8--- > ;; myname is a string taken from user input > (bbdb-search (bbdb-records) (if (> (length myname) 0) myname nil) nil > nil) (if (> (length myname) 0) (bbdb-search (bbdb-records) myname nil nil) (bbdb-search (bbdb-records) nil nil nil)) Stefan