From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: How does letf work? Date: Wed, 29 Jan 2014 01:35:47 +0100 Organization: Aioe.org NNTP Server Message-ID: <87r47rpqtf.fsf@nl106-137-194.student.uu.se> References: NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1390956011 9388 80.91.229.3 (29 Jan 2014 00:40:11 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 29 Jan 2014 00:40:11 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Wed Jan 29 01:40:20 2014 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 1W8JCW-0008BE-36 for geh-help-gnu-emacs@m.gmane.org; Wed, 29 Jan 2014 01:40:20 +0100 Original-Received: from localhost ([::1]:40037 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8JCV-0006dl-Iq for geh-help-gnu-emacs@m.gmane.org; Tue, 28 Jan 2014 19:40:19 -0500 Original-Path: usenet.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!news.stack.nl!aioe.org!.POSTED!not-for-mail Original-Newsgroups: gnu.emacs.help Original-Lines: 30 Original-NNTP-Posting-Host: VVbyYd/iFZoeWNmD9i++cQ.user.speranza.aioe.org Original-X-Complaints-To: abuse@aioe.org User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) X-Notice: Filtered by postfilter v. 0.8.2 Cancel-Lock: sha1:1iF4UXa+LX1WcSFDLl1J6MTKakc= Mail-Copies-To: never Original-Xref: usenet.stanford.edu gnu.emacs.help:203471 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:95740 Archived-At: Florian Beck writes: > The docstring of letf says: "This is the analogue of > let', but with generalized variables (in the sense of > setf') for the PLACEs." (letf (((cdr test-x) '(a b c d))) (message "%s" test-x) ; says '(KEY a b c d) (cdr test-x) ) ; => (a b c d) (And `... (nth 1 test-x)' => 'a, and so on.) But: (letf (((cdr test-x) '(a b c d))) (message "%s" test-x) ; says '(KEY a b c d) test-x) ; => '(KEY 1 2 3 4) `letf' (or `cl-letf') resets the values when it exits: > On exit, either normally or because of a `throw' or > error, the PLACEs are set back to their original > values. So perhaps this inconsistency is due to the implementation of that. -- underground experts united: http://user.it.uu.se/~embe8573