From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Ken Raeburn Newsgroups: gmane.emacs.devel Subject: Re: GC: marking traversal and pure symbols Date: Fri, 6 Jul 2007 08:02:26 -0400 Message-ID: <6D6F6C83-4A4D-4267-85FF-A67C679E108A@raeburn.org> References: <468CEDAF.20706@yandex.ru> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 (Apple Message framework v752.2) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1183723432 20688 80.91.229.12 (6 Jul 2007 12:03:52 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Fri, 6 Jul 2007 12:03:52 +0000 (UTC) Cc: Dmitry Antipov , emacs-devel@gnu.org To: rms@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Jul 06 14:03:51 2007 connect(): Connection refused Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1I6mXO-00029h-33 for ged-emacs-devel@m.gmane.org; Fri, 06 Jul 2007 14:03:50 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1I6mXN-0001gk-Jc for ged-emacs-devel@m.gmane.org; Fri, 06 Jul 2007 08:03:49 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1I6mWE-0000YI-Ix for emacs-devel@gnu.org; Fri, 06 Jul 2007 08:02:38 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1I6mWD-0000XU-Qm for emacs-devel@gnu.org; Fri, 06 Jul 2007 08:02:37 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1I6mWD-0000XI-FE for emacs-devel@gnu.org; Fri, 06 Jul 2007 08:02:37 -0400 Original-Received: from alnrmhc11.comcast.net ([206.18.177.51]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1I6mW6-0002Ti-Nk; Fri, 06 Jul 2007 08:02:30 -0400 Original-Received: from raeburn.org (c-65-96-188-63.hsd1.ma.comcast.net[65.96.188.63]) by comcast.net (alnrmhc11) with ESMTP id <20070706120229b1100bvp38e>; Fri, 6 Jul 2007 12:02:29 +0000 Original-Received: from [69.25.196.100] (fwoosh.raeburn.org [69.25.196.100]) by raeburn.org (8.12.11/8.12.11) with ESMTP id l66C2SN9022848; Fri, 6 Jul 2007 08:02:28 -0400 (EDT) In-Reply-To: X-Mailer: Apple Mail (2.752.2) X-detected-kernel: NetCache Data OnTap 5.x X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:74390 Archived-At: On Jul 6, 2007, at 00:38, Richard Stallman wrote: > We can't make Qnil pure, because its plist can be written. > (It can also be defined as a function, though that would be an > ugly thing to do.) I've seen that done, many years ago -- and the person who did it ran into interesting problems. I think there was some Emacs code shipped that had a loop over a list testing to see if the car of the list was a function, or something like that -- depending on the fact that nil doesn't (normally) have a function binding to break the loop. I have no idea if the problem is still present. It wouldn't strike me as a bad thing to make the function slot of Qnil unsettable this way... Ken