From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Emanuel Berg Newsgroups: gmane.emacs.help Subject: Re: Lions & tigers & variables - Oh my! [was: Lisp error on function :documentation] Date: Wed, 19 Oct 2022 07:16:11 +0200 Message-ID: <877d0wbdgk.fsf@dataswamp.org> References: Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31772"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) To: help-gnu-emacs@gnu.org Cancel-Lock: sha1:f7RH3gBlTiDsXezQum1dwwej/qo= Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Oct 19 11:55:25 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 1ol5nJ-000848-JM for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 19 Oct 2022 11:55:25 +0200 Original-Received: from localhost ([::1]:52960 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ol5nI-0002UT-5I for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 19 Oct 2022 05:55:24 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:53518) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ol1RH-000242-4c for help-gnu-emacs@gnu.org; Wed, 19 Oct 2022 01:16:23 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:32920) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ol1RE-0006YP-OU for help-gnu-emacs@gnu.org; Wed, 19 Oct 2022 01:16:22 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1ol1RD-0004Jd-H1 for help-gnu-emacs@gnu.org; Wed, 19 Oct 2022 07:16:19 +0200 X-Injected-Via-Gmane: http://gmane.org/ Mail-Followup-To: help-gnu-emacs@gnu.org Mail-Copies-To: never 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-Mailman-Approved-At: Wed, 19 Oct 2022 05:51:04 -0400 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" Xref: news.gmane.io gmane.emacs.help:140148 Archived-At: Drew Adams wrote: > Yes, all of that is OT. What's not OT is that for Emacs > users, _in particular_, special (global) vars can be > quite useful. > > Precisely _because_ they can let you reach across existing > code without modifying it [...] But then that existing code has to use that variable. So for the dynamic/special _and_ global variables to be useful, they have to actually be used ;) Let's take it from another side, I just asked what you can do with lexical/static variables in `let'-closures, and answered you can share them between two or several `defun', and you can use them to keep persistent/state data between calls to functions. I don't know if that's a good answer in the sense that it is complete but I know it is a good answer in the sense that it is true because I have used let-closures exactly like that. So we know they can do that, and global variables obviously also can, but can global variables do something else that they cannot? That they can be accessed from anywhere? So when you want that, that's when you should use them? Okay, but then when typically do you want that? When what they describe is so general it is just so likely that a lot of stuff, including future stuff, will use them, so it is just impractical to put them in a closure? Actually in a way the whole global closure is just one big closure for global variables I guess. It's the top-level closure since there is nothing outside of it ... -- underground experts united https://dataswamp.org/~incal