From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Sebastian Tennant Newsgroups: gmane.emacs.help Subject: Re: A macro and an unwanted containing list in the resulting form Date: Wed, 23 May 2007 15:51:02 +0300 Message-ID: <87y7jfwvnt.fsf@moley.org> References: <873b1nye2g.fsf@moley.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: sea.gmane.org 1179924598 14136 80.91.229.12 (23 May 2007 12:49:58 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Wed, 23 May 2007 12:49:58 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed May 23 14:49:46 2007 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 1HqqHi-0004RC-5r for geh-help-gnu-emacs@m.gmane.org; Wed, 23 May 2007 14:49:46 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HqqHj-00064E-TP for geh-help-gnu-emacs@m.gmane.org; Wed, 23 May 2007 08:49:47 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1HqqHV-00061Z-Jd for help-gnu-emacs@gnu.org; Wed, 23 May 2007 08:49:33 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1HqqHS-0005wC-4C for help-gnu-emacs@gnu.org; Wed, 23 May 2007 08:49:32 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1HqqHS-0005w4-0K for help-gnu-emacs@gnu.org; Wed, 23 May 2007 08:49:30 -0400 Original-Received: from main.gmane.org ([80.91.229.2] helo=ciao.gmane.org) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1HqqHR-0004TU-Hx for help-gnu-emacs@gnu.org; Wed, 23 May 2007 08:49:29 -0400 Original-Received: from list by ciao.gmane.org with local (Exim 4.43) id 1HqqHC-0001Ms-0q for help-gnu-emacs@gnu.org; Wed, 23 May 2007 14:49:14 +0200 Original-Received: from 85.105.17.65 ([85.105.17.65]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 23 May 2007 14:49:14 +0200 Original-Received: from sebyte by 85.105.17.65 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 23 May 2007 14:49:14 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 41 Original-X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: 85.105.17.65 User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/22.0.95 (gnu/linux) Cancel-Lock: sha1:jMDtkwLdf4jFMjX0iqrx06ptitU= X-detected-kernel: Linux 2.6, seldom 2.4 (older, 4) 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:44326 Archived-At: Quoth "Juanma Barranquero" : > On 5/23/07, Sebastian Tennant wrote: >> (cond (((equal e "hello") (message "hi")) >> ^((equal e "goodbye") (message "bye")))) >> | ^ >> | | >> +--------- unwanted list -------------+ >> >> Clearly my approach is wrong (because this is how mapcar behaves), so >> what is the best way to go about this? > > Try with > > (defmacro build-cond (alist) > (append '(cond) > (mapcar '(lambda (each) > (cons (list 'equal 'my-var (car each)) (list (cdr each)))) > alist))) Hmm. Thanks a lot. It works. (Now I need to grok exactly why). > Is there any reason to make the argument of build-cond an alist? You >could try > > (defmacro build-cond (&rest conds) > (append '(cond) > (mapcar '(lambda (each) > (cons (list 'equal 'my-var (car each)) (list (cdr each)))) > conds))) > > and then use > > (build-cond ("hello" . (message "hi")) > ("goodbye" . (message "bye")) The reason for the alist is the clauses are being passed as one of a number of arguments to a function call. Thanks again. Sebastian