From mboxrd@z Thu Jan 1 00:00:00 1970 Path: main.gmane.org!not-for-mail From: storm@cua.dk (Kim F. Storm) Newsgroups: gmane.emacs.devel Subject: Re: Old CUA and new keyboard.c (was: Problem with latest CVS version of keyboard.c (solved) ) Date: 13 Jun 2002 00:06:27 +0200 Sender: emacs-devel-admin@gnu.org Message-ID: <5xelfcup7g.fsf@kfs2.cua.dk> References: <00D3E07D.7CEA4D23.00A66750@netscape.net> <200206121519.g5CFJRr18872@rum.cs.yale.edu> NNTP-Posting-Host: localhost.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: main.gmane.org 1023916014 22385 127.0.0.1 (12 Jun 2002 21:06:54 GMT) X-Complaints-To: usenet@main.gmane.org NNTP-Posting-Date: Wed, 12 Jun 2002 21:06:54 +0000 (UTC) Cc: emacs-devel@gnu.org, ponced16@netscape.net (David Ponce) Return-path: Original-Received: from quimby.gnus.org ([80.91.224.244]) by main.gmane.org with esmtp (Exim 3.33 #1 (Debian)) id 17IFKQ-0005ow-00 for ; Wed, 12 Jun 2002 23:06:54 +0200 Original-Received: from fencepost.gnu.org ([199.232.76.164]) by quimby.gnus.org with esmtp (Exim 3.12 #1 (Debian)) id 17IFiO-0000LM-00 for ; Wed, 12 Jun 2002 23:31:41 +0200 Original-Received: from localhost ([127.0.0.1] helo=fencepost.gnu.org) by fencepost.gnu.org with esmtp (Exim 3.34 #1 (Debian)) id 17IFK0-0006Ps-00; Wed, 12 Jun 2002 17:06:28 -0400 Original-Received: from mail.filanet.dk ([195.215.206.179]) by fencepost.gnu.org with smtp (Exim 3.34 #1 (Debian)) id 17IFJL-0006N8-00 for ; Wed, 12 Jun 2002 17:05:47 -0400 Original-Received: from kfs2.cua.dk.cua.dk (unknown [10.1.82.3]) by mail.filanet.dk (Postfix) with SMTP id C6D137C016; Wed, 12 Jun 2002 21:05:43 +0000 (GMT) Original-To: "Stefan Monnier" In-Reply-To: <200206121519.g5CFJRr18872@rum.cs.yale.edu> Original-Lines: 78 User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3.50 Errors-To: emacs-devel-admin@gnu.org X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.0.9 Precedence: bulk List-Help: List-Post: List-Subscribe: , List-Id: Emacs development discussions. List-Unsubscribe: , List-Archive: Xref: main.gmane.org gmane.emacs.devel:4805 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:4805 "Stefan Monnier" writes: > cua-2.10 puts a CUA-prefix-handler function on C-x in key-translation-map. > This function will remap C-x to something else or to the same > thing depending on the situation. Problem is, this function > is used for C-c as well (and maybe other keys), so it needs to be > told what was the key that triggered it. > It figures this out by using last-input-char (it also uses this-command-keys > although I'm not quite sure why and what it does with it). I don't quite remember why this-command-keys was used, but probably it had something to do with only wanting to remap the first C-c or C-x in a key sequence. In any case, that's irrelevant now. > > So the problem is that key-translation-map used to be applied immediately > and thus CUA-prefix-handler was called as soon as the user hit C-x, whereas > the new code waits to see whether this C-x starts a function-key > sequence (in which case key-translation-map should not be applied yet) > and thus CUA-prefix-handler is only called once the user hits the next key. So the new code fundamentally changes the way key-translation-map works. Before, it would be activated immediately, now it is delayed until the next key is typed. If I still had to rely on the key-translation-map for cua, I'd definitely object to this change in behaviour, as it would make it impossible to intercept the C-x and C-c prefix keys... which does require the "immediate" activation (it obviously cannot wait for the next key to be typed). Since cua no longer depends on this behaviour, and since I'm not aware of any other code which depends on this, I really don't care much about the issue. Also, I'm uncertain whether the behaviour that I used in cua was actually documented, or it just worked that way by chance. But as we have seen, there may be some nasty effects experienced by users which upgrade from, say, 21.1 to 21.4 if they already have the old cua-mode in their load-path; in that case, emacs 21.4 will behave very strange (read: buggy). So we need to address that issue! I was wondering why you need to wait for the next character after a C-x or C-c to see if they start a function key... I don't think those specific keys will ever do that, so maybe you should only delay the use of key-translation-map in case the key is actually a potential candidate for starting a function key. > > Let's say she wants to do C-x C-f so with the new keyboard.c code, > when CUA-prefix-handler is called last-input-char is not C-x but C-f, > so CUA gets all confused and we end up with C-f C-f whereas > CUA thought it wasn't changing anything. > That is another problem -- caused by key-translation-map not being activated immediately; as explained above, that is necessary for (old) cua to work properly. So if it does that, last-input-char would be correct again. > Not knowing exactly what the semantics of last-input-char are supposed > to be and how/if functions in key-translation-map should be allowed > to use it or should use some other way to figure out what key sequence > triggered them, I'm wondering if my fix introduced a "significant" > incompatibility or not. This is a major incompatibility, but whether it is "significant" depends on whether we can find some way of preventing an existing old cua-mode package from being loaded instead of the build-in package if the user upgrades to 21.4. > Also if it should be fixed, I'm not sure how to go about it. See suggestion above. -- Kim F. Storm http://www.cua.dk