From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Pascal J. Bourguignon" Newsgroups: gmane.emacs.help Subject: Re: How to rescind a defun? Date: Sat, 19 May 2012 04:52:19 +0200 Organization: Informatimago Message-ID: <87r4ug6fx8.fsf@kuiper.lan.informatimago.com> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: dough.gmane.org 1337396115 12546 80.91.229.3 (19 May 2012 02:55:15 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Sat, 19 May 2012 02:55:15 +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 May 19 04:55:13 2012 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1SVZp2-0000D6-OO for geh-help-gnu-emacs@m.gmane.org; Sat, 19 May 2012 04:55:12 +0200 Original-Received: from localhost ([::1]:35163 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SVZp2-0005hV-3V for geh-help-gnu-emacs@m.gmane.org; Fri, 18 May 2012 22:55:12 -0400 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 38 Original-X-Trace: individual.net 6SISkCkyZe6BKUKVpZ1p4A4htvykUEMjJb6tazrSM3aveQEIW+JKonNAL4HYMXbBG0 Cancel-Lock: sha1:M2JkY2JhZWQzMWZjZDAyNWE4YzVjZTNjMjNiOWM5YzUxODljM2I1Nw== sha1:KSxVKKlhzb/beZPDra9cyY7+ENw= Face: iVBORw0KGgoAAAANSUhEUgAAADAAAAAwAQMAAABtzGvEAAAABlBMVEUAAAD///+l2Z/dAAAA oElEQVR4nK3OsRHCMAwF0O8YQufUNIQRGIAja9CxSA55AxZgFO4coMgYrEDDQZWPIlNAjwq9 033pbOBPtbXuB6PKNBn5gZkhGa86Z4x2wE67O+06WxGD/HCOGR0deY3f9Ijwwt7rNGNf6Oac l/GuZTF1wFGKiYYHKSFAkjIo1b6sCYS1sVmFhhhahKQssRjRT90ITWUk6vvK3RsPGs+M1RuR mV+hO/VvFAAAAABJRU5ErkJggg== X-Accept-Language: fr, es, en User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.4 (gnu/linux) Original-Xref: usenet.stanford.edu gnu.emacs.help:192488 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:84893 Archived-At: kj writes: > If, during an Emacs session, one evaluates a defun that (inadvertently) > redefines an existing function, is it possible to undo this? If you do that a lot, you could implement defun to do that. (require 'cl) (setf (symbol-function 'emacs-defun) (symbol-function 'defun)) (defmacro defun (name lambda-list &rest body) `(progn (when (fboundp ',name) (push (symbol-function ',name) (get ',name 'old-defuns))) (emacs-defun ,name ,lambda-list ,@body))) (defun pop-defun* (name) (setf (symbol-function name) (pop (get name 'old-defuns)))) (defmacro pop-defun (name) `(pop-defun* ',name)) (defun f () 42) (f) --> 42 (defun f () 33) (f) --> 33 (pop-defun f) (f) --> 42 Now of course you need to define that early, and load all the libraries after it, so that they use your defun instead of the native emacs-defun. -- __Pascal Bourguignon__ http://www.informatimago.com/ A bad day in () is better than a good day in {}.