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: Always using let* Date: Tue, 16 Sep 2014 16:49:50 -0400 Message-ID: References: <87fvfukmso.fsf@Equus.decebal.nl> <93faab1c-96bd-4188-9686-3869fc027601@default> <732966c5-a667-4fc7-9d07-8da315862ce2@googlegroups.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1410901858 8627 80.91.229.3 (16 Sep 2014 21:10:58 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 16 Sep 2014 21:10:58 +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 Sep 16 23:10:51 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 1XU01J-0006r0-Iv for geh-help-gnu-emacs@m.gmane.org; Tue, 16 Sep 2014 23:10:41 +0200 Original-Received: from localhost ([::1]:40872 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XU01J-00040l-3W for geh-help-gnu-emacs@m.gmane.org; Tue, 16 Sep 2014 17:10:41 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:53553) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XU007-00030d-6I for help-gnu-emacs@gnu.org; Tue, 16 Sep 2014 17:09:34 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XTzzx-000091-BR for help-gnu-emacs@gnu.org; Tue, 16 Sep 2014 17:09:27 -0400 Original-Received: from plane.gmane.org ([80.91.229.3]:56971) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XTzzx-00006W-5b for help-gnu-emacs@gnu.org; Tue, 16 Sep 2014 17:09:17 -0400 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1XTzhN-0003pJ-VP for help-gnu-emacs@gnu.org; Tue, 16 Sep 2014 22:50:05 +0200 Original-Received: from 69-165-145-6.dsl.teksavvy.com ([69.165.145.6]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 16 Sep 2014 22:50:05 +0200 Original-Received: from monnier by 69-165-145-6.dsl.teksavvy.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 16 Sep 2014 22:50:05 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 19 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 69-165-145-6.dsl.teksavvy.com User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) Cancel-Lock: sha1:jXuBXe+5SWchZtC/EECZ+tA+b7g= 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:99964 Archived-At: > But, quite often, I have several independent variable, except one or two. > So, I would use "let" rather than "let*", but don't bind these variables > and then use "setq" in the body of the let: > (let ((a (val-for-a)) > (b (val-for-b)) > ... > x y) ; depend on a b > (setq x (val-for-x a b)) > (setq y (val-for-y a b)) > ... In some cases, `setq' can't be easily avoided, but otherwise, I strongly recommend let* over let+setq. If it depended on me, I'd swap the two since in most cases you could use let*, it's very rare to really need `let'. Stefan