From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Idempotency of add-hook wrt lambda expressions Date: Thu, 5 Mar 2009 16:45:32 +0000 Message-ID: <20090305164532.GC1855@muc.de> References: <74F2CF19-2E71-473F-A352-A628B3B29A8E@gmail.com> <861vtcxpt1.fsf@lola.quinscape.zz> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1236270256 5653 80.91.229.12 (5 Mar 2009 16:24:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 5 Mar 2009 16:24:16 +0000 (UTC) Cc: David Kastrup , emacs-devel@gnu.org To: Geoff Gole Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Mar 05 17:25:32 2009 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1LfGO3-0003Wi-G0 for ged-emacs-devel@m.gmane.org; Thu, 05 Mar 2009 17:25:32 +0100 Original-Received: from localhost ([127.0.0.1]:47390 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LfGMi-0006Lf-1r for ged-emacs-devel@m.gmane.org; Thu, 05 Mar 2009 11:24:08 -0500 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LfGLG-0005zk-UK for emacs-devel@gnu.org; Thu, 05 Mar 2009 11:22:38 -0500 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LfGLG-0005z8-8I for emacs-devel@gnu.org; Thu, 05 Mar 2009 11:22:38 -0500 Original-Received: from [199.232.76.173] (port=41664 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LfGLG-0005z1-2j for emacs-devel@gnu.org; Thu, 05 Mar 2009 11:22:38 -0500 Original-Received: from colin.muc.de ([193.149.48.1]:1536 helo=mail.muc.de) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LfGLF-0002BQ-Fm for emacs-devel@gnu.org; Thu, 05 Mar 2009 11:22:37 -0500 Original-Received: (qmail 9065 invoked by uid 3782); 5 Mar 2009 16:22:35 -0000 Original-Received: from acm.muc.de (pD9E5203E.dip.t-dialin.net [217.229.32.62]) by colin2.muc.de (tmda-ofmipd) with ESMTP; Thu, 05 Mar 2009 17:22:31 +0100 Original-Received: (qmail 2846 invoked by uid 1000); 5 Mar 2009 16:45:32 -0000 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.9i X-Delivery-Agent: TMDA/1.1.5 (Fettercairn) X-Primary-Address: acm@muc.de X-detected-operating-system: by monty-python.gnu.org: FreeBSD 4.6-4.9 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:109473 Archived-At: On Thu, Mar 05, 2009 at 08:53:23PM +0900, Geoff Gole wrote: > > Also, in some cases you can't avoid lambda, namely when using computed > > functions. > Can't you avoid this with (add-hook 'hook (progn (fset symbol > calculated-definition) symbol)) or similar? Probably, yes. But who'd want to? One of the reasons for using a lambda is to save having to think up a function name, and to save cluttering up one's .emacs, or whatever. Compare (add-hook 'foo-mode-hook (lambda (some-minor-mode 1))) with (defun switch-some-minor-mode-on () (some-minor-mode 1)) (add-hook 'foo-mode-hook 'switch-some-minor-mode-on) . -- Alan Mackenzie (Nuremberg, Germany).