From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Gregory Heytings via "Emacs development discussions." Newsgroups: gmane.emacs.devel Subject: Re: A solution to display completion candidates after point in a minibuffer Date: Sat, 03 Oct 2020 12:31:54 +0000 Message-ID: References: Reply-To: Gregory Heytings Mime-Version: 1.0 Content-Type: text/plain; format=flowed; charset=US-ASCII Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28809"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Alpine 2.22 (NEB 394 2020-01-19) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Oct 03 14:33:25 2020 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 1kOgj7-0007P8-8C for ged-emacs-devel@m.gmane-mx.org; Sat, 03 Oct 2020 14:33:25 +0200 Original-Received: from localhost ([::1]:48790 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kOgj6-0007HY-9K for ged-emacs-devel@m.gmane-mx.org; Sat, 03 Oct 2020 08:33:24 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33402) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kOghr-0006P9-R1 for emacs-devel@gnu.org; Sat, 03 Oct 2020 08:32:09 -0400 Original-Received: from mx.sdf.org ([205.166.94.24]:55625) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kOghp-0001lT-ED for emacs-devel@gnu.org; Sat, 03 Oct 2020 08:32:07 -0400 Original-Received: from sdf.org (IDENT:ghe@otaku.sdf.org [205.166.94.8]) by mx.sdf.org (8.15.2/8.14.5) with ESMTPS id 093CVvFS025011 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits) verified NO); Sat, 3 Oct 2020 12:31:57 GMT Original-Received: (from ghe@localhost) by sdf.org (8.15.2/8.12.8/Submit) id 093CVuu8019663; Sat, 3 Oct 2020 12:31:56 GMT In-Reply-To: Received-SPF: pass client-ip=205.166.94.24; envelope-from=ghe@sdf.org; helo=mx.sdf.org X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/03 07:25:52 X-ACL-Warn: Detected OS = ??? X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham 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:256997 Archived-At: > > I'd be uneasy using such code without some vague understanding about > *why* it works. > I studied this in a bit more detail. What happens in the normal case (with icomplete-mode, icomplete-separator set to "\n", and window-scroll-functions set to nil) is the following: 1. redisplay_internal() calls resize_mini_window() and redisplay_windows(), 2. redisplay_windows() calls redisplay_window_0(), which calls redisplay_window(), and the "recenter" part of redisplay_window() is executed. This happens twice (for each window in the frame) before redisplay_internal() returns. It happens twice because FRAME_GARBAGED_P, because the windows have been resized, which means that the "goto retry" jump is executed. This means that run_window_scroll_functions() is called twice (which has of course no effect if window-scroll-functions is nil). When window-scroll-functions is set to start-display-at-beginning-of-minibuffer, the same happens, except of course that start-display-at-beginning-of-minibuffer is executed twice. The first time the "recenter" part of redisplay_window() is executed, start-display-at-beginning-of-minibuffer sets w->force_start and w->start. Then resize_mini_window() sets w->start again, but redisplay_window() is called again, and this time it is its "force_start" part that is executed, which calls run_window_scroll_functions(), after which try_window() updates w->start to the window-start value set in window-scroll-functions.