From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Correct line/column numbers in byte compiler messages [Was: GNU is looking for Google Summer of Code Projects] Date: Fri, 20 Mar 2020 19:18:46 +0000 Message-ID: <20200320191846.GA5255@ACM> References: <20200319203449.GA4180@ACM> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="21663"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Rocky Bernstein , Stefan Monnier , emacs-devel To: Andrea Corallo Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Mar 20 20:19:30 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 1jFNB4-0005WN-GQ for ged-emacs-devel@m.gmane-mx.org; Fri, 20 Mar 2020 20:19:30 +0100 Original-Received: from localhost ([::1]:58092 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jFNB3-0005Yh-Ha for ged-emacs-devel@m.gmane-mx.org; Fri, 20 Mar 2020 15:19:29 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54485) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jFNAT-00052j-25 for emacs-devel@gnu.org; Fri, 20 Mar 2020 15:18:54 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jFNAR-00087g-I4 for emacs-devel@gnu.org; Fri, 20 Mar 2020 15:18:52 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:57667 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1jFNAR-00087D-98 for emacs-devel@gnu.org; Fri, 20 Mar 2020 15:18:51 -0400 Original-Received: (qmail 16823 invoked by uid 3782); 20 Mar 2020 19:18:50 -0000 Original-Received: from acm.muc.de (p4FE15C8D.dip0.t-ipconnect.de [79.225.92.141]) by colin.muc.de (tmda-ofmipd) with ESMTP; Fri, 20 Mar 2020 20:18:47 +0100 Original-Received: (qmail 5267 invoked by uid 1000); 20 Mar 2020 19:18:46 -0000 Content-Disposition: inline In-Reply-To: X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 193.149.48.1 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:245608 Archived-At: Hello, Andrea. On Thu, Mar 19, 2020 at 20:43:15 +0000, Andrea Corallo wrote: > Alan Mackenzie writes: > > "More precise line numbers" is a misconstruction, even though I've used > > such language myself in the past. Line numbers don't come from a > > physical instrument which measures with, say +-1% accuracy. CORRECT > > line (and column) numbers are what we need. > > You will recall that the output of correct line/column numbers for byte > > compiler messages is a solved problem. I solved it and presented the > > fix in December 2018. This fix was rejected because it made Emacs > > slightly slower. > > In the 3½ years I've been grappling with this problem, I've tried all > > sorts of things like "fat cons cells". They don't work, and can't work. > > They can't work because large chunks of our software chew up and spit > > out cons cells with gay abandon (I'm talking about the byte compiler and > > things like cconv.el here). More to the point, users' macros chew up and > > spit out cons cells, and we have no control over them. So whilst we > > could, with a lot of tedious effort, clean up our own software to > > preserve cons cells (believe me, I've tried), this would fail in users' > > macros. > > Since then I've worked a fair bit on creating a "double" Emacs core, one > > core being for normal use, the other for byte compiling. There's a fair > > amount of work still to do on this, but I know how to do it. The problem > > is that I have been discouraged by the prospect of having this solution > > vetoed too, since it will make Emacs quite a bit bigger. > > I don't think it is fair to give this problem to a group of summer > > coders. It is too hard a problem, both technically and politically. > Hi Alan, > Sorry I'm new to Emacs development, where can be found the code of your > attempt? Is it in a feature branch? It's in the branch scratch/accurate-warning-pos. The commit which converted the unfinished work to a bug fix was: commit 2e04ddadab266d245a3bd0f6c19223ea515bdb90 Author: Alan Mackenzie Date: Fri Nov 30 14:55:48 2018 +0000 Sundry amendments to branch scratch/accurate-warning-pos. (except, I think it still outputs two positions for each warning message: the traditional one, and the new correct one). > Thanks > Andrea > -- > akrl@sdf.org -- Alan Mackenzie (Nuremberg, Germany).