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: Redefining functions and variables Date: Wed, 28 Jul 2010 22:37:03 +0200 Organization: Informatimago Message-ID: <87hbjjibrk.fsf@kuiper.lan.informatimago.com> References: <68e690c9-aece-461d-afe9-ca9115ceaee5@m1g2000vbh.googlegroups.com> <76fd4dc4-a964-4629-90e2-329e1b83fd8d@h25g2000vba.googlegroups.com> <876300fnpk.fsf@fh-trier.de> <55e481e3-b894-499f-80b3-1c96b2c338ce@d37g2000yqm.googlegroups.com> <61db17c1-8c30-44a1-b96e-9eec802156fe@j8g2000yqd.googlegroups.com> <87tynjl9x3.fsf@fh-trier.de> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-Trace: dough.gmane.org 1291853863 21024 80.91.229.12 (9 Dec 2010 00:17:43 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Thu, 9 Dec 2010 00:17:43 +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 Dec 09 01:17:38 2010 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 4.69) (envelope-from ) id 1PQUCW-00089g-Jc for geh-help-gnu-emacs@m.gmane.org; Thu, 09 Dec 2010 01:17:36 +0100 Original-Received: from localhost ([127.0.0.1]:46986 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PQUCV-0001YL-Ik for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Dec 2010 19:17:35 -0500 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 44 Original-X-Trace: individual.net +TbxxMCFg5sxqzqBlGfoXA022Ywxjc2NERRyWzdhsdHF1Wl6/U Cancel-Lock: sha1:YjdmMjI5MzhmZmY0MTAxMTM2ZDM0MGE0Y2M0YTA2MTIyOTg1NTY4Zg== sha1:VtcFe5HPzjMZvKHWFmRLVcCvRQE= 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/23.2 (gnu/linux) Original-Xref: usenet.stanford.edu gnu.emacs.help:180159 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:76282 Archived-At: Andreas Politz writes: > Elena writes: > >> On Jul 28, 7:51 am, Elena wrote: >>> > Of course this leads to an endless recursive loop, expanding your macro >>> > again and again ... >>> >>> Then I should have tested the macro with `macroexpand-all' instead of >>> `macroexpand'. However, I've tried using the macro, and it seemed to >>> work, albeit it choked on the unquoted symbol passed to `fboundp'. >> >> I think it seemed to work because the macro was interpreted, therefore >> it was expanded only once before the failure. > > Don't know, but defining `defun' as a macro usually deletes the original > subst (which is a special form, which is kind of like a macro). > > (defvar defun-subst (symbol-function 'defun)) > > (defmacro defun (name args &rest body) > `(defun ,name ,args ,@body)) > > (defun foo ()) > ;; Enters the debugger because of recursion limit reached. > > ;; Restore original defun > (fset 'defun defun-subst) Another way: (defvar old-defun 'defun) ; the symbol! (unintern 'defun) (defmacro defun (name args &rest body) `(progn (message "defining %S" name) (,old-defun ,name ,args ,@body))) In this case there's no infinite recursion. -- __Pascal Bourguignon__ http://www.informatimago.com/