From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.help Subject: Re: Returning variable "references" under lexical binding Date: Mon, 20 May 2013 23:18:42 -0400 Message-ID: References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1369106362 7238 80.91.229.3 (21 May 2013 03:19:22 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 21 May 2013 03:19:22 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Tue May 21 05:19:21 2013 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 1Ued6e-0005Td-OH for geh-help-gnu-emacs@m.gmane.org; Tue, 21 May 2013 05:19:20 +0200 Original-Received: from localhost ([::1]:46831 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ued6e-0001yd-8G for geh-help-gnu-emacs@m.gmane.org; Mon, 20 May 2013 23:19:20 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:46913) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ued6Q-0001x7-SP for help-gnu-emacs@gnu.org; Mon, 20 May 2013 23:19:11 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Ued6I-000550-2S for help-gnu-emacs@gnu.org; Mon, 20 May 2013 23:19:06 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:33253) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Ued6H-00054o-Rw for help-gnu-emacs@gnu.org; Mon, 20 May 2013 23:18:57 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Ued6F-0005NH-8q for help-gnu-emacs@gnu.org; Tue, 21 May 2013 05:18:55 +0200 Original-Received: from 69-165-154-5.dsl.teksavvy.com ([69.165.154.5]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 21 May 2013 05:18:55 +0200 Original-Received: from monnier by 69-165-154-5.dsl.teksavvy.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 21 May 2013 05:18:55 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 28 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 69-165-154-5.dsl.teksavvy.com User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) Cancel-Lock: sha1:jNLYUbgwbKdbksmemXNwJg9XSnQ= X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 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:90934 Archived-At: > (defun start-my-timer () > (let ((timer (gensym))) > ;; ... (set timer (make-timer ...)) ... > timer)) [...] > (defun cancel-my-timer (timer) > (cancel-timer (symbol-value timer))) Why not (defun start-my-timer () (let ((timer (make-timer ...)) ... timer)) (defun cancel-my-timer (timer) (cancel-timer timer)) > The documenentation for lexical variables cautions against treating them > as symbols, specifically stating that functions like symbol-value will > not work. In your above code, you're not treating variables as symbols. You're just storing a symbol inside a variable, which is fine. E.g. a problematic example would have been (set 'timer ...) or (symbol-value 'timer). Stefan