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: Thu, 29 Jul 2010 12:03:28 +0200 Organization: Informatimago Message-ID: <877hkeiozz.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> <87hbjjibrk.fsf@kuiper.lan.informatimago.com> <08217e84-b4a0-4dd0-afbf-abd4d762c759@w30g2000yqw.googlegroups.com> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: dough.gmane.org 1291851767 12438 80.91.229.12 (8 Dec 2010 23:42:47 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Wed, 8 Dec 2010 23:42:47 +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 00:42:42 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 1PQTej-00015a-UZ for geh-help-gnu-emacs@m.gmane.org; Thu, 09 Dec 2010 00:42:42 +0100 Original-Received: from localhost ([127.0.0.1]:54876 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PQTaa-0007QX-Om for geh-help-gnu-emacs@m.gmane.org; Wed, 08 Dec 2010 18:38:24 -0500 Original-Path: usenet.stanford.edu!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 84 Original-X-Trace: individual.net aGFOgs5+Z8BIZ7yUfy4Wgg/aTGbi1ILZCbrNUitUgBMMrxNmYD Cancel-Lock: sha1:ZmQ5NzRjMjEyODVmMTgwYzE2YjM0ZjJmZjA4ZDMyOTZkNjc4MjUyMA== sha1:TMPnu0AECz4nRWQhnuXuevTUvxU= 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:180178 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:76213 Archived-At: Elena writes: > My modified macro is below. Why ',name is expanded as ... (as shown by > `macroexpand-all'? > > (defvar old-defun 'defun) ; the symbol! > (unintern 'defun) > > (defmacro defun (name args &rest body) > `(progn > ;; `load-file-name' is not null only if we are loading a > file. > (when (and load-file-name > (fboundp ',name)) > (message "Warning: %s is being redefined in %s." > (symbol-name ',name) > load-file-name) > (,old-defun ,name ,args > ,@body)))) It is not. (macroexpand '(defun. test (a) (+ 1 a))) ;; --> (progn (when (and load-file-name (fboundp (quote test))) (message "Warning: %s is being redefined in %s." (symbol-name (quote test)) load-file-name) (defun test (a) (+ 1 a)))) the "..." are only used to display the list when print-length or eval-expression-print-length are not nil. See also print-level and eval-expression-print-level. %s can format symbols too: (format ">> %s <<" 'example) ;; --> ">> example <<" And you had your the old defun inside the when! (defmacro defun (name args &rest body) `(progn ;; `load-file-name' is not null only if we are loading a file. (when (and load-file-name (fboundp ',name)) (message "Warning: %s is being redefined in %s." ',name load-file-name)) (,old-defun ,name ,args ,@body))) Note: while name is known at macroexpansion time, you should refrain to insert it in the string like this: (message ,(format "Warning: %s is being redefined in %%s." name) load-file-name) since name could contain percents and then you'd have build a wrong format string for message. If you want to do that, you must escape the percents: (message ,(format "Warning: %s is being redefined in %%s." (escape-percent name)) load-file-name) with: (defun escape-percent (string-designator) (let ((string (etypecase string-designator (string string-designator) (symbol (symbol-name string-designator)) (character (string string-designator))))) (unsplit-string (split-string string "%" nil) "%%"))) (defun unsplit-string (string-list &rest separator) "Does the inverse than split-string. If no separator is provided then a simple space is used." (if (null separator) (setq separator " ") (if (= 1 (length separator)) (setq separator (car separator)) (error "unsplit-string: Too many separator arguments."))) (if (not (char-or-string-p separator)) (error "unsplit-string: separator must be a string or a char.")) (apply 'concat (list-insert-separator string-list separator))) (mapcar 'escape-percent '("abc" abc % %make- make-10%-of-profit %%internal%%)) ;; --> ("abc" "abc" "%%" "%%make-" "make-10%%-of-profit" "%%%%internal%%%%") -- __Pascal Bourguignon__ http://www.informatimago.com/