From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: sbaugh@catern.com Newsgroups: gmane.emacs.devel Subject: Re: Horizontal centering in the display engine Date: Wed, 14 Apr 2021 11:25:41 -0400 Message-ID: <87fszsvqfe.fsf@catern.com> References: <87fszuvy7p.fsf@catern.com> <83czuy112a.fsf@gnu.org> <877dl6vvax.fsf@catern.com> <83blai0y3i.fsf@gnu.org> <8735vtx62w.fsf@catern.com> <8335vt1hiw.fsf@gnu.org> <87tuo9uh9m.fsf@catern.com> <83k0p5ylkb.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="34620"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: emacs-devel@gnu.org Cancel-Lock: sha1:YwaQ6Ie5Vw218LGPEmxZcb7cF40= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Apr 14 17:31:30 2021 Return-path: Envelope-to: ged-emacs-devel@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 1lWhUI-0008sk-N8 for ged-emacs-devel@m.gmane-mx.org; Wed, 14 Apr 2021 17:31:30 +0200 Original-Received: from localhost ([::1]:42148 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWhUH-0007Vr-LR for ged-emacs-devel@m.gmane-mx.org; Wed, 14 Apr 2021 11:31:29 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:57550) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWhSv-0006xK-Lw for emacs-devel@gnu.org; Wed, 14 Apr 2021 11:30:05 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:40406) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWhSu-0000sQ-9O for emacs-devel@gnu.org; Wed, 14 Apr 2021 11:30:05 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lWhSs-0006dX-Be for emacs-devel@gnu.org; Wed, 14 Apr 2021 17:30:02 +0200 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.249, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:268055 Archived-At: Eli Zaretskii writes: > No, you only need to update them when the length of some of the lines > changes. That is why the values are different for each line: the > lines will usually have different lengths, and that length is part of > the value of :align-to. Right? Oh, that's true, I only need to update them when the length of the line changes. >> > And if we go one level higher, I guess you intend to write a >> > post-command-hook that recalculates the :align-to specs whenever text >> > changes, is that right? Or how did you plan on taking text changes >> > into consideration? >> >> No, I want my :align-to specs to stay the same as text changes. > > You want the display engine to evaluate the function call for you? > That's not possible at the moment, the expression language accepted by > :align-to is somewhat limited. It can automatically react to changes > in a variable's value, but in that case it must be the same variable > for all the lines, and that contradicts what you want to do. Yes, that makes sense. So I'm asking about how difficult it would be to add a new element to the :align-to expression language, one which specifies the width of the current line. Arbitrary function calls is not necessary for what I want, just something specifically for the width of the current line, in the same way there's already elements for left-fringe etc.