From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: pjb@informatimago.com (Pascal J. Bourguignon) Newsgroups: gmane.emacs.help Subject: Re: Element-Relative Sequence Insertion Date: Thu, 11 Jun 2009 15:01:18 +0200 Organization: Anevia SAS Message-ID: <7cski62ach.fsf@pbourguignon.anevia.com> References: <7czlcf0wu9.fsf@pbourguignon.informatimago.com> <5f86d760-77b2-4ac0-897b-4eb8deca43fe@a36g2000yqc.googlegroups.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1244727956 22349 80.91.229.12 (11 Jun 2009 13:45:56 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 11 Jun 2009 13:45:56 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Thu Jun 11 15:45:54 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 1MEkbJ-00084T-S3 for geh-help-gnu-emacs@m.gmane.org; Thu, 11 Jun 2009 15:45:54 +0200 Original-Received: from localhost ([127.0.0.1]:38761 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MEkbJ-0007Tu-3q for geh-help-gnu-emacs@m.gmane.org; Thu, 11 Jun 2009 09:45:53 -0400 Original-Path: news.stanford.edu!headwall.stanford.edu!newsfeed.esat.net!colt.net!feeder.news-service.com!news.netcologne.de!newsfeed-fusi2.netcologne.de!newsfeed.straub-nv.de!feeder1-2.proxad.net!proxad.net!feeder1-1.proxad.net!cleanfeed4-a.proxad.net!nnrp17-1.free.fr!not-for-mail Original-Newsgroups: gnu.emacs.help Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en X-Disabled: X-No-Archive: no User-Agent: Gnus/5.101 (Gnus v5.10.10) Emacs/22.2 (gnu/linux) Cancel-Lock: sha1:NjNjZDRjMjA4ODFlMzJkZWM1YTIzNjA3NmRjMGMxOTZkMGY4MWFjNA== Original-Lines: 63 Original-NNTP-Posting-Date: 11 Jun 2009 15:01:18 MEST Original-NNTP-Posting-Host: 88.170.236.224 Original-X-Trace: 1244725278 news-1.free.fr 20704 88.170.236.224:60893 Original-X-Complaints-To: abuse@proxad.net Original-Xref: news.stanford.edu gnu.emacs.help:169939 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:65170 Archived-At: Nordlöw writes: > On 11 Juni, 14:38, p...@informatimago.com (Pascal J. Bourguignon) > wrote: >> Nordlöw writes: >> > How do I insert an element (object) relative to another in a sequence >> > (or list in my case)? Example: >> >> > (insert-after 'X '(a b c) 'b)  => '(a b X c) >> > (insert-before 'X '(a b c) b)  => '(a X b c) >> >> This is not what you want.  You don't what these function to return a >> 2-element lists, the first of which is the symbol quote.  Unless >> you're doing meta-programming you never want to have such a result. >> >> You wan this: >> >>    (insert-after 'X '(a b c)  'b)  -->  (a b X c) >>    (insert-before 'X '(a b c) 'b)  -->  (a X b c) >> >> Also, you may want to mention whether your insert-after and >> insert-before function are destructive or non-destructive.  Since you >> show as only specification examples using literal data, we will assume >> you want them to be non-destructive. >> >> So you do that, just by doing it.  There's nothing simplier. >> >> (qrsha vafreg-nsgre (arj yvfg byq) >>    (pbaq ((ahyy yvfg) '()) >>          ((rdy byq (pne yvfg))  (pbaf (pne yvfg) (pbaf arj (pqe yvfg)))) >>          (g (pbaf (pne yvfg) (vafreg-nsgre arj (pqe yvfg) byq))))) >> >> (qrsha vafreg-orsber (arj yvfg byq) >>    (pbaq ((ahyy yvfg) '()) >>          ((rdy byq (pne yvfg))  (pbaf arj yvfg)) >>          (g (pbaf (pne yvfg) (vafreg-orsber arj (pqe yvfg) byq))))) >> >> -- >> __Pascal Bourguignon__ > > But how do I implement insert-after() and insert-before()? I guess the > code in the end doesn't do anything meaningful :) It does, but you have to decrypt it first. Could you implement first something simplier than insert-after or insert-before? For example, could you implement a function map, which builds a new list with the result of calling a function to each element of a list: (defun map (function list) ...) (map (lambda (x) (1+ x)) '(1 2 3)) --> (2 3 4) (map (lambda (x) (1+ x)) '()) --> () If you can do that, then you should be able to implement insert-before and insert-after adding only one line. -- __Pascal Bourguignon__