From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Should records be able to mimic primitive types? Date: Mon, 12 Jun 2017 13:47:52 -0400 Message-ID: References: <8777899d-ca8e-212c-b8bf-2f8da4c54836@cs.ucla.edu> <83zidg57xv.fsf@gnu.org> <83tw3l3zv4.fsf@gnu.org> <83o9tt3yu4.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1497289700 16649 195.159.176.226 (12 Jun 2017 17:48:20 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 12 Jun 2017 17:48:20 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Jun 12 19:48:17 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 1dKTRm-0003sC-O6 for ged-emacs-devel@m.gmane.org; Mon, 12 Jun 2017 19:48:14 +0200 Original-Received: from localhost ([::1]:39387 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dKTRq-0001LY-5U for ged-emacs-devel@m.gmane.org; Mon, 12 Jun 2017 13:48:18 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:53896) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dKTRh-0001LH-FS for emacs-devel@gnu.org; Mon, 12 Jun 2017 13:48:10 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dKTRe-00031I-Ew for emacs-devel@gnu.org; Mon, 12 Jun 2017 13:48:09 -0400 Original-Received: from [195.159.176.226] (port=39259 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dKTRe-000314-7p for emacs-devel@gnu.org; Mon, 12 Jun 2017 13:48:06 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1dKTRT-00030K-9W for emacs-devel@gnu.org; Mon, 12 Jun 2017 19:47:55 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 12 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:AZfgMyJqTw8lDxfbSJgQsrDyUEU= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 195.159.176.226 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:215598 Archived-At: >> The reason why I disagree with them is because they are too costly >> compared to the likelihood they'll ever help catch a bug > That'd be in the "defenses are too expensive" department, right? Right. I just wanted to clarify that "expensive" is a relative notion: in the case under discussion, the extra check is just a single `memq` test on a fairly short list, so it's pretty cheap in itself; the only reason why I find it too expensive is that the expected gain is just extremely small. Stefan