From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Help getting started debugging Emacs on macOS Sierra Date: Fri, 11 Aug 2017 19:08:28 +0300 Message-ID: <83lgmqqe83.fsf@gnu.org> References: <87556904-541c-6ef5-5a2b-9b7199ffb603@cs.ucla.edu> <7b152bb1-5768-633c-8b7a-172cc6227a26@cs.ucla.edu> <83valuqvmw.fsf@gnu.org> <83poc2qjc3.fsf@gnu.org> <83o9rmqh0j.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1502467866 20484 195.159.176.226 (11 Aug 2017 16:11:06 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 11 Aug 2017 16:11:06 +0000 (UTC) Cc: emacs-devel@gnu.org To: Itai Berli Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Aug 11 18:10:57 2017 Return-path: Envelope-to: ged-emacs-devel@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 1dgCWT-0004aj-Cq for ged-emacs-devel@m.gmane.org; Fri, 11 Aug 2017 18:10:53 +0200 Original-Received: from localhost ([::1]:53115 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dgCWZ-00026Y-Gv for ged-emacs-devel@m.gmane.org; Fri, 11 Aug 2017 12:10:59 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:39699) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dgCUS-0000s2-Ad for emacs-devel@gnu.org; Fri, 11 Aug 2017 12:08:49 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dgCUO-0000pg-7Z for emacs-devel@gnu.org; Fri, 11 Aug 2017 12:08:48 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:46950) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dgCUO-0000pV-5I; Fri, 11 Aug 2017 12:08:44 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:4816 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1dgCUN-00053u-1N; Fri, 11 Aug 2017 12:08:44 -0400 In-reply-to: (message from Itai Berli on Fri, 11 Aug 2017 18:34:08 +0300) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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:217442 Archived-At: > From: Itai Berli > Date: Fri, 11 Aug 2017 18:34:08 +0300 > Cc: Emacs developers > > > Tell me what you want to do and with what text, and then I might be able to help you do > that in a more useful way. > > I just want to get more familiar with the bidi algorithm and the way it is implemented by Emacs. I'd like to try > various small phrases, such as the ones that can be found in this article: > https://www.w3.org/International/articles/inline-bidi-markup/uba-basics After entering GDB, set a breakpoint in a function called Fredraw_display, then run Emacs ("run -Q"). Insert the text you want, then move point to its beginning and type "C-x =". Remember the buffer position displayed as result, let's call it POS. Then type "M-x redraw-display RET". GDB will get control, and you can now put breakpoints where you want. For tracing through the bidi.c code, I'd suggest this: (gdb) break bidi_get_next_char_visually if bidi_it->charpos == POS (gdb) continue When the breakpoint in bidi_get_next_char_visually breaks, you can step through the code using the "step" and "next" commands (you have tool-bar buttons for them). Note that bidi_get_next_char_visually is called for each character the display engine wants to display, so when it returns, it puts in bidi_it->charpos the position of the next character in visual order.