From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: When are unused overlays garbage collected? Date: Thu, 27 May 2021 18:23:18 +0200 Message-ID: <87wnrkcfih.fsf@mbork.pl> References: <87v978u3nd.fsf@mbork.pl> <874keqdr5v.fsf@mbork.pl> <83y2c1ad2n.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="26624"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: mu4e 1.1.0; emacs 28.0.50 Cc: help-gnu-emacs@gnu.org To: Eli Zaretskii Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu May 27 18:28:46 2021 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 1lmIsI-0006f0-8F for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 27 May 2021 18:28:46 +0200 Original-Received: from localhost ([::1]:51990 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lmIsH-0000vK-43 for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 27 May 2021 12:28:45 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lmInE-0001O2-Bq for help-gnu-emacs@gnu.org; Thu, 27 May 2021 12:23:33 -0400 Original-Received: from mail.mojserwer.eu ([195.110.48.8]:40302) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lmInA-00083D-KP; Thu, 27 May 2021 12:23:32 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 33555E6ACD; Thu, 27 May 2021 18:23:26 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id w68UwGyqcwRP; Thu, 27 May 2021 18:23:20 +0200 (CEST) Original-Received: from localhost (83.8.191.179.ipv4.supernova.orange.pl [83.8.191.179]) by mail.mojserwer.eu (Postfix) with ESMTPSA id 4DAB2E62EA; Thu, 27 May 2021 18:23:20 +0200 (CEST) In-reply-to: <83y2c1ad2n.fsf@gnu.org> Received-SPF: pass client-ip=195.110.48.8; envelope-from=mbork@mbork.pl; helo=mail.mojserwer.eu X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 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:130258 Archived-At: On 2021-05-26, at 14:34, Eli Zaretskii wrote: >> From: Marcin Borkowski >> Date: Wed, 26 May 2021 07:01:48 +0200 >> Cc: help-gnu-emacs@gnu.org >> >> > Markers share some of their implementation with overlays, but because >> > markers do not affect the display and because there is nothing >> > corresponding to `overlays-at' or `overlays-in', Emacs goes through the >> > trouble of GC'ing those markers which are still reachable via the >> > buffer's internal variables (its list of markers) as long as they're not >> > reachable some other way, of course. >> >> Thanks, too, this is pretty interesting. I assume one possible reason >> for not having `markers-in' (analogous to `overlays-in') is that an >> overlay (even without any variable pointing to it, IOW, a "name" for it) >> has some "semantics" (properties), so it can be "guessed" what it is >> for; for markers, we would only know that "someone wanted to remember >> this position, but we have no idea why/what for", so why even bother >> keeping it? > > I think we don't have markers-in because it isn't needed. overlays-in > is needed when you want to find the next or the previous overlay, or > when you need to know what faces contribute to the appearance of a > character at certain position. There's no such need for markers. Well, that obviously doesn't contradict what I was saying - but thanks for the explanation (mine was of course just hypothesizing). Best, -- Marcin Borkowski http://mbork.pl