From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Lexical let and setq Date: Fri, 13 Sep 2013 23:46:36 -0400 Message-ID: References: <871u51ll93.fsf@yandex.ru> <0b29ebee-8ed4-47e2-816b-910a013a0898@default> <878uz0e02m.fsf_-_@maru2.md5i.com> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1379130416 18054 80.91.229.3 (14 Sep 2013 03:46:56 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 14 Sep 2013 03:46:56 +0000 (UTC) Cc: emacs-devel@gnu.org To: Michael Welsh Duggan Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Sep 14 05:46:58 2013 Return-path: Envelope-to: ged-emacs-devel@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 1VKgoy-0007dE-4s for ged-emacs-devel@m.gmane.org; Sat, 14 Sep 2013 05:46:56 +0200 Original-Received: from localhost ([::1]:51863 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKgox-0006C0-LL for ged-emacs-devel@m.gmane.org; Fri, 13 Sep 2013 23:46:55 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:60688) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKgon-0006Bm-SC for emacs-devel@gnu.org; Fri, 13 Sep 2013 23:46:53 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VKgog-00011r-Jh for emacs-devel@gnu.org; Fri, 13 Sep 2013 23:46:45 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.182]:26441) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VKgog-00011m-FA for emacs-devel@gnu.org; Fri, 13 Sep 2013 23:46:38 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av4EABK/CFG4rxBo/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLNBIUGA0kiB4GwS2RCgOkeoFegxM X-IPAS-Result: Av4EABK/CFG4rxBo/2dsb2JhbABEvw4Xc4IeAQEEAVYjBQsLNBIUGA0kiB4GwS2RCgOkeoFegxM X-IronPort-AV: E=Sophos;i="4.84,565,1355115600"; d="scan'208";a="27717283" Original-Received: from 184-175-16-104.dsl.teksavvy.com (HELO pastel.home) ([184.175.16.104]) by ironport2-out.teksavvy.com with ESMTP/TLS/ADH-AES256-SHA; 13 Sep 2013 23:43:02 -0400 Original-Received: by pastel.home (Postfix, from userid 20848) id 6D5B462CC9; Fri, 13 Sep 2013 23:46:36 -0400 (EDT) In-Reply-To: <878uz0e02m.fsf_-_@maru2.md5i.com> (Michael Welsh Duggan's message of "Fri, 13 Sep 2013 20:09:05 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3.50 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 206.248.154.182 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:163334 Archived-At: > The primary reason I have seen the (let (foo) (setq foo ...)) idiom is > in looping code. That one is OK, since recursion is not supported efficiently. The problem is when people use the above because they're writing (poor) C code in Elisp (e.g. they begin their functions with a big let declaring all the local vars that they may use later on in the function). Stefan