From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#24633: highlight-region func using (window-hscroll) in :align-to spec can cause inf loop Date: Sun, 09 Oct 2016 15:42:32 +0300 Message-ID: <83h98lg0cn.fsf@gnu.org> References: <87vax5vuoj.fsf@users.sourceforge.net> <834m4nhz1t.fsf@gnu.org> <874m4mwyj2.fsf@users.sourceforge.net> <837f9ihg8l.fsf@gnu.org> <87y41yved9.fsf@users.sourceforge.net> <83y41yfwam.fsf@gnu.org> <87lgxxvh6o.fsf@users.sourceforge.net> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1476017006 26494 195.159.176.226 (9 Oct 2016 12:43:26 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sun, 9 Oct 2016 12:43:26 +0000 (UTC) Cc: 24633@debbugs.gnu.org To: npostavs@users.sourceforge.net Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Sun Oct 09 14:43:22 2016 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1btDRg-0005K0-OJ for geb-bug-gnu-emacs@m.gmane.org; Sun, 09 Oct 2016 14:43:12 +0200 Original-Received: from localhost ([::1]:44383 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btDRg-0000eJ-UY for geb-bug-gnu-emacs@m.gmane.org; Sun, 09 Oct 2016 08:43:12 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41521) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btDRa-0000e2-It for bug-gnu-emacs@gnu.org; Sun, 09 Oct 2016 08:43:07 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1btDRW-00044S-8y for bug-gnu-emacs@gnu.org; Sun, 09 Oct 2016 08:43:05 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:43210) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btDRW-00044M-6M for bug-gnu-emacs@gnu.org; Sun, 09 Oct 2016 08:43:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1btDRV-0007fC-Sl for bug-gnu-emacs@gnu.org; Sun, 09 Oct 2016 08:43:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 09 Oct 2016 12:43:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 24633 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 24633-submit@debbugs.gnu.org id=B24633.147601696029428 (code B ref 24633); Sun, 09 Oct 2016 12:43:01 +0000 Original-Received: (at 24633) by debbugs.gnu.org; 9 Oct 2016 12:42:40 +0000 Original-Received: from localhost ([127.0.0.1]:49400 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1btDRA-0007eZ-Iq for submit@debbugs.gnu.org; Sun, 09 Oct 2016 08:42:40 -0400 Original-Received: from eggs.gnu.org ([208.118.235.92]:50427) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1btDR9-0007eO-Kq for 24633@debbugs.gnu.org; Sun, 09 Oct 2016 08:42:39 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1btDR0-0003ph-Vp for 24633@debbugs.gnu.org; Sun, 09 Oct 2016 08:42:34 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:35417) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btDR0-0003pK-SW; Sun, 09 Oct 2016 08:42:30 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:4711 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1btDQy-0004ks-50; Sun, 09 Oct 2016 08:42:29 -0400 In-reply-to: <87lgxxvh6o.fsf@users.sourceforge.net> (npostavs@users.sourceforge.net) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 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" Xref: news.gmane.org gmane.emacs.bugs:124268 Archived-At: > From: npostavs@users.sourceforge.net > Cc: 24633@debbugs.gnu.org > Date: Sun, 09 Oct 2016 08:29:51 -0400 > > Anyway, it doesn't seem worth going through this complexity. I just > wonder if there is some way to stop bad lisp code from triggering a hard > lockup. Can the display engine notice if it's looping and throw some > kind of error? Maybe unset pre-redisplay-functions? I don't see how we could detect loops in general. But for the particular case of infinite hscrolling, we could perhaps count the number of times hscroll_windows was called and returned a non-zero value, and forcibly stop the loop after some reasonable number of iterations. Patches welcome. Could be a nice small project for someone who wants to gain practice with hacking the display engine. > >> >> According to `(elisp) Pixel Specification', > >> >> > >> >> The form NUM specifies a fraction of the default frame font height > >> >> or width. The form `(NUM)' specifies an absolute number of pixels. > >> > > >> > I admire your courage in reading that documentation and then writing > >> > stuff like the above, which the documentation doesn't mention even > >> > remotely. > >> > >> Uh, not sure how to read this, is it irony? > > > > Only a little. I find this area severely under-documented. > > The grammar in the doc seems complete to me. Do you really think that a formal grammar, whether accurate/complete or not, is a good way of describing a feature?