From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#18739: 24.3; Request for a hook to be provided when scrolling will move the cursor Date: Thu, 16 Oct 2014 09:44:34 -0400 Message-ID: References: <83wq813vyx.fsf@gnu.org> <83r3y84iuv.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1413467150 1180 80.91.229.3 (16 Oct 2014 13:45:50 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 16 Oct 2014 13:45:50 +0000 (UTC) Cc: josh+gnu@nispio.net, 18739@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Thu Oct 16 15:45:35 2014 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XelMw-0007yT-6m for geb-bug-gnu-emacs@m.gmane.org; Thu, 16 Oct 2014 15:45:30 +0200 Original-Received: from localhost ([::1]:50518 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XelMv-0003DX-HD for geb-bug-gnu-emacs@m.gmane.org; Thu, 16 Oct 2014 09:45:29 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:53991) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XelMi-0003CH-Cn for bug-gnu-emacs@gnu.org; Thu, 16 Oct 2014 09:45:24 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XelMa-0008M4-Mu for bug-gnu-emacs@gnu.org; Thu, 16 Oct 2014 09:45:16 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:53854) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XelMa-0008Lf-Kc for bug-gnu-emacs@gnu.org; Thu, 16 Oct 2014 09:45:08 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1XelMU-0005iI-4g for bug-gnu-emacs@gnu.org; Thu, 16 Oct 2014 09:45:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 16 Oct 2014 13:45:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 18739 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 18739-submit@debbugs.gnu.org id=B18739.141346709021931 (code B ref 18739); Thu, 16 Oct 2014 13:45:01 +0000 Original-Received: (at 18739) by debbugs.gnu.org; 16 Oct 2014 13:44:50 +0000 Original-Received: from localhost ([127.0.0.1]:45418 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XelMH-0005hf-Rk for submit@debbugs.gnu.org; Thu, 16 Oct 2014 09:44:50 -0400 Original-Received: from ironport2-out.teksavvy.com ([206.248.154.181]:25184) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1XelM3-0005hG-IT for 18739@debbugs.gnu.org; Thu, 16 Oct 2014 09:44:48 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArUGAIDvNVNFxKjo/2dsb2JhbABZgwaDSsA9gRcXdIImAQEEViMQCzQSFBgNJIgM0hkXjnoHhDgEqRmBaoFxgVsh X-IPAS-Result: ArUGAIDvNVNFxKjo/2dsb2JhbABZgwaDSsA9gRcXdIImAQEEViMQCzQSFBgNJIgM0hkXjnoHhDgEqRmBaoFxgVsh X-IronPort-AV: E=Sophos;i="4.97,753,1389762000"; d="scan'208";a="94346954" Original-Received: from 69-196-168-232.dsl.teksavvy.com (HELO pastel.home) ([69.196.168.232]) by ironport2-out.teksavvy.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 16 Oct 2014 09:44:34 -0400 Original-Received: by pastel.home (Postfix, from userid 20848) id 4BC9085A2; Thu, 16 Oct 2014 09:44:34 -0400 (EDT) In-Reply-To: <83r3y84iuv.fsf@gnu.org> (Eli Zaretskii's message of "Thu, 16 Oct 2014 09:41:12 +0300") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.4.50 (gnu/linux) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:94607 >> >> It would be helpful to have a hook that would be called before any >> >> scrolling command moves the cursor. In other words, I want to be >> >> notified when an update to the display will force the location of >> >> `point' to change in the current buffer. >> > What's wrong with window-scroll-functions? >> But these are also called when point is not affected, right? > Yes. But it's easy to detect that situation, I think. Is it? I think the main reason why I ask is because I truly have no idea when window-scroll-functions is called. You seem to be somewhat familiar with it, so could you try and clarify it in the docstring? Currently I see "List of functions to call before redisplaying a window with scrolling" and "Note that these functions are also called by `set-window-buffer'". Here are some of the questions this brings up for me: - is it called during set-window-buffer itself, or is it called in the first redisplay after set-window-buffer? - what means "redisplaying a window with scrolling" exactly? Does it mean "redisplay with a different window-start then during the last redisplay"? Does that include the case where window-start is changed so as to follow point or is it only the cases where window-start was changed explicitly by a scrolling command? - how could a window-scroll-function distinguish the 3 cases: "set-window-buffer", "used a scroll command", "moved point out of viewport". I tried already a few times to understand window-scroll-functions, but so far it has eluded me. FWIW, I found 3 kinds of uses: - A crutch from when jit-lock didn't exist (in linum and lazy-lock). - A way to try and keep a window fully empty showing only point-max by calling set-window-start with the same window-start (in follow-mode). Not clear exactly why this should work, and arguably goes against the warning in window-scroll-functions's docstring. - Do fancy auto-scrolling in eshell/em-smart (which does exactly what window-scroll-functions's docstring warns not to do, AFAICT), calling redisplay internally. Stefan