From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: curious why private variables are rare Date: Sat, 19 Nov 2022 22:53:47 -0500 Message-ID: References: Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="30445"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:TFRNaZ9aINBq1aDHK5ywjpSK2w8= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Sun Nov 20 04:54:43 2022 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1owbPn-0007ok-AN for geh-help-gnu-emacs@m.gmane-mx.org; Sun, 20 Nov 2022 04:54:43 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1owbP6-0007da-Ax; Sat, 19 Nov 2022 22:54:00 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1owbP5-0007dS-18 for help-gnu-emacs@gnu.org; Sat, 19 Nov 2022 22:53:59 -0500 Original-Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1owbP2-0005vF-J2 for help-gnu-emacs@gnu.org; Sat, 19 Nov 2022 22:53:58 -0500 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1owbOz-0006jr-5K for help-gnu-emacs@gnu.org; Sun, 20 Nov 2022 04:53:53 +0100 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=geh-help-gnu-emacs@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:141063 Archived-At: > even when var is only used by fun. but you could do: > > (let ((var ...)) > (defun fun ...)) Indeed. > so I am just curious why the usual thing is usual. is it the above > reasons? or am i missing some bigger things? Most likely it's because it started working quite late in the history of ELisp, so habits were taken at a stage where it wasn't an option. Side note: the above works, but the compiler doesn't understand it well enough, which leads to some minor/invisible effects (the .elc file is marginally less efficient) and some less invisible effects (code after that `let` will get spurious warnings (about a call to unknown function) if it calls `fun`) :-( Stefan