From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 29d1c72: Introduce new value t for compilation-context-lines to eliminate scrolling Date: Tue, 27 Aug 2019 20:05:20 +0000 Message-ID: <20190827200520.GC20676@ACM> References: <20190825102322.19558.22771@vcs0.savannah.gnu.org> <20190825102323.5080620CD5@vcs0.savannah.gnu.org> <20190825190637.GE4724@ACM> <838srhghoc.fsf@gnu.org> <20190826162651.GA4137@ACM> <83ef17gaar.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="249099"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mutt/1.10.1 (2018-07-13) Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 27 22:05:37 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1i2hih-0012dv-Bw for ged-emacs-devel@m.gmane.org; Tue, 27 Aug 2019 22:05:35 +0200 Original-Received: from localhost ([::1]:57226 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2hif-0007Es-QI for ged-emacs-devel@m.gmane.org; Tue, 27 Aug 2019 16:05:33 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:45943) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2hiX-0007EU-3L for emacs-devel@gnu.org; Tue, 27 Aug 2019 16:05:26 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i2hiV-0001vL-MN for emacs-devel@gnu.org; Tue, 27 Aug 2019 16:05:24 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:50022 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1i2hiV-0001uV-Fd for emacs-devel@gnu.org; Tue, 27 Aug 2019 16:05:23 -0400 Original-Received: (qmail 21055 invoked by uid 3782); 27 Aug 2019 19:12:32 -0000 Original-Received: from acm.muc.de (p4FE15C47.dip0.t-ipconnect.de [79.225.92.71]) by colin.muc.de (tmda-ofmipd) with ESMTP; Tue, 27 Aug 2019 21:12:31 +0200 Original-Received: (qmail 20893 invoked by uid 1000); 27 Aug 2019 20:05:20 -0000 Content-Disposition: inline In-Reply-To: <83ef17gaar.fsf@gnu.org> X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 193.149.48.1 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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" Xref: news.gmane.org gmane.emacs.devel:239626 Archived-At: Hello, Eli. On Mon, Aug 26, 2019 at 19:29:16 +0300, Eli Zaretskii wrote: > > Date: Mon, 26 Aug 2019 16:26:51 +0000 > > Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org > > From: Alan Mackenzie > > Should I have been aware of this? > What is "this" in this context? The display margins or how to use > them with overlays? I think, more the first of these. > > Somehow, in the elisp manual, it seems buried under several levels > > of chapters, sections, and sub-sections. > Well, Emacs is a large program, and display features in particular are > a legion... I found implementing these margins (see patch in separate post) to be particularly difficult. There is no complete example of how to do this on the "Display Margins" elisp manual page. There, the word "property" is used, rather than "text property or overlay property", leaving me uncertain of whether I could have implemented this "=>" in the margin solely with overlays. I was uncertain, right up till near when I had the thing ready, whether the variables implementing this need to be buffer local or not. (It also didn't help that I tried at first to put the `display' text properties on overlay-arrow-string, which, of course, can't work.) Also, the setup seems wierd. Why isn't there a direct `margin' overlay property, much the same way there's a `before-string' overlay property? Instead, what we have is a required "dummy" `before-string', which is supplanted by a `display' text property on it. It just seems a strange way of implementing it. This certainly doesn't promote easy understanding. IMHO, of course. -- Alan Mackenzie (Nuremberg, Germany).