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: How do lisp gurus truncate? Date: Thu, 23 Jul 2009 21:44:03 +0200 Organization: Informatimago Message-ID: <87r5w7jibg.fsf@galatea.local> References: NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1248381808 30638 80.91.229.12 (23 Jul 2009 20:43:28 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 23 Jul 2009 20:43:28 +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 Jul 23 22:43:21 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 1MU58D-0004c8-24 for geh-help-gnu-emacs@m.gmane.org; Thu, 23 Jul 2009 22:43:14 +0200 Original-Received: from localhost ([127.0.0.1]:57189 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1MU58C-0008T1-Iq for geh-help-gnu-emacs@m.gmane.org; Thu, 23 Jul 2009 16:43:12 -0400 Original-Path: news.stanford.edu!headwall.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 52 Original-X-Trace: individual.net lPRd5Pnf4F/O/jZlgMm3nwu3mndBa7AeFJJVaMYlxd9MpKymm7 Cancel-Lock: sha1:YWQ1YjdjMDRlNjMxODEwNjFhMGJmOTYwODc5NDc4NTc2YTAxNzljMA== sha1:x/Pp6PYwh4tHmz5dQJC2LoXT8TM= 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/5.1008 (Gnus v5.10.8) Emacs/22.3 (darwin) Original-Xref: news.stanford.edu gnu.emacs.help:171177 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:66367 Archived-At: Lennart Borgman writes: > I want to truncate an ordered list if the rest of the values are > bigger than some limit. I just wrote some code like this one to do > that, but there must be some more standard way of doing that, or? > > (when nxml-where-first-change-pos > (setq nxml-where-path 'dummy nxml-where-path) > (let ((path nxml-where-path)) > (while (cdr path) > (when (> (nth 1 (nth 1 path)) nxml-where-first-change-pos) > (setcdr path nil)) > (setq path (cdr path)))) > (setq nxml-where-path (cdr nxml-where-path))) (require 'cl) (defun* nsplit-list-if (predicate list) "Modifies the list cutting it just before the first element for which the predicate returns true. Returns the cut list and the rest." (loop for current on (cons nil list) while (cdr current) when (funcall predicate (cadr current)) do (return-from nsplit-list-if (values list (prog1 (cdr current) (setf (cdr current) nil))))) (values list nil)) (nsplit-list-if (lambda (x) (< 3 x)) (list 0 1 2 3 4 5 6 7)) --> ((0 1 2 3) (4 5 6 7)) (defun split-list-if (predicate list) "Returns a copy of the list up to the first element for which the predicate returns true, and the rest of the list." (loop with result = '() for current on list do (if (funcall predicate (car current)) (return (values (nreverse result) current)) (push (car current) result)) finally (return (values (nreverse result) nil)))) (split-list-if (lambda (x) (< 3 x)) '(0 1 2 3 4 5 6 7)) --> ((0 1 2 3) (4 5 6 7)) -- __Pascal Bourguignon__