From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: "Drew Adams" Newsgroups: gmane.emacs.devel Subject: Q on NaN Date: Fri, 24 Jun 2005 12:06:15 -0700 Message-ID: NNTP-Posting-Host: main.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1119641958 8567 80.91.229.2 (24 Jun 2005 19:39:18 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Fri, 24 Jun 2005 19:39:18 +0000 (UTC) Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Jun 24 21:39:17 2005 Return-path: Original-Received: from lists.gnu.org ([199.232.76.165]) by ciao.gmane.org with esmtp (Exim 4.43) id 1Dlu0q-0003jX-Ro for ged-emacs-devel@m.gmane.org; Fri, 24 Jun 2005 21:38:53 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Dlu7w-0002vY-Cd for ged-emacs-devel@m.gmane.org; Fri, 24 Jun 2005 15:46:12 -0400 Original-Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Dltz5-0006FQ-24 for emacs-devel@gnu.org; Fri, 24 Jun 2005 15:37:03 -0400 Original-Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Dltz3-0006Eg-6U for emacs-devel@gnu.org; Fri, 24 Jun 2005 15:37:02 -0400 Original-Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1DltyK-0005fD-Eu for emacs-devel@gnu.org; Fri, 24 Jun 2005 15:36:16 -0400 Original-Received: from [141.146.126.229] (helo=agminet02.oracle.com) by monty-python.gnu.org with esmtp (TLS-1.0:DHE_RSA_3DES_EDE_CBC_SHA:24) (Exim 4.34) id 1DltYw-0004Hu-MW for emacs-devel@gnu.org; Fri, 24 Jun 2005 15:10:02 -0400 Original-Received: from agminet02.oracle.com (localhost [127.0.0.1]) by agminet02.oracle.com (Switch-3.1.7/Switch-3.1.7) with ESMTP id j5OJ6JVx004674 for ; Fri, 24 Jun 2005 14:06:19 -0500 Original-Received: from rgmsgw300.us.oracle.com (rgmsgw300.us.oracle.com [138.1.186.49]) by agminet02.oracle.com (Switch-3.1.7/Switch-3.1.7) with ESMTP id j5OJ6I1o004662 for ; Fri, 24 Jun 2005 14:06:19 -0500 Original-Received: from rgmsgw300.us.oracle.com (localhost [127.0.0.1]) by rgmsgw300.us.oracle.com (Switch-3.1.4/Switch-3.1.0) with ESMTP id j5OJ6I1c005702 for ; Fri, 24 Jun 2005 13:06:18 -0600 Original-Received: from dradamslap (dhcp-amer-whq-csvpn-gw3-141-144-80-138.vpn.oracle.com [141.144.80.138]) by rgmsgw300.us.oracle.com (Switch-3.1.4/Switch-3.1.0) with SMTP id j5OJ6HG3005695 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO) for ; Fri, 24 Jun 2005 13:06:18 -0600 Original-To: "Emacs-Devel" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1506 Importance: Normal X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE 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:39449 X-Report-Spam: http://spam.gmane.org/gmane.emacs.devel:39449 Consider this: (condition-case nil (setq foo (/ 0.0 0.0)) (arith-error nil)) In older versions of Emacs (at least prior to April 2005 CVS), this would evaluate to nil. Now, it evaluates to -0.0NaN (on Windows, at least), which breaks the encompassing code (which tests the above expression for non-nil). Fair enough. I can modify the code like so: (and (condition-case nil (setq foo (/ 0.0 0.0)) (arith-error nil)) (bar foo)) ; foo must be a number, not a NaN What function do I use for bar? `numberp' doesn't work, since (numberp -0.0NaN) is non-nil. That seems odd to me, since NaN means "not a number" and numberp means "a number", but I guess I can live with a little oddness. In the Elisp manual, I didn't find a predicate to test for NaN.