From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id 602811F5AE for ; Sat, 1 Aug 2020 19:41:17 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id B14B3120A0C; Sun, 2 Aug 2020 04:40:44 +0900 (JST) Received: from xtrwkhkc.outbound-mail.sendgrid.net (xtrwkhkc.outbound-mail.sendgrid.net [167.89.16.28]) by neon.ruby-lang.org (Postfix) with ESMTPS id 74816120A0A for ; Sun, 2 Aug 2020 04:40:42 +0900 (JST) Received: by filterdrecv-p3mdw1-7ff865655c-vtsg9 with SMTP id filterdrecv-p3mdw1-7ff865655c-vtsg9-19-5F25C554-1A 2020-08-01 19:41:08.56185636 +0000 UTC m=+264289.082045472 Received: from herokuapp.com (unknown) by geopod-ismtpd-5-0 (SG) with ESMTP id wAgsaQNdSTq0lpk8v67LnA for ; Sat, 01 Aug 2020 19:41:08.511 +0000 (UTC) Date: Sat, 01 Aug 2020 19:41:08 +0000 (UTC) From: marcandre-ruby-core@marc-andre.ca Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 75272 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17098 X-Redmine-Issue-Author: chrisseaton X-Redmine-Sender: marcandre X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?6=2FIMxCQLDposcQf5wmbDAtfaKduBAO0bKyhL3BGZtMQ5q7K2TvpbN6A7JIyt9E?= =?us-ascii?Q?aO4jYDZr8lS81LdymCnZkcRO8GyVYri8BM3Nt+G?= =?us-ascii?Q?kZ8e9y1YM=2F33E+8mR+IciX8ElkkxY5j21xEnUua?= =?us-ascii?Q?O3ETtnyzCYJ0bHS1IVrghVHNcp2OVSRvLEah=2FPY?= =?us-ascii?Q?tspI7T+x6ZbD1qBOEvpIk5t6LEiLWCz5RRCFe8V?= =?us-ascii?Q?XPSjaja=2FbEWviAqjohJEuyUNijDYcLJ5gefGcR?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99443 Subject: [ruby-core:99443] [Ruby master Bug#17098] Float#negative? reports negative zero as not negative X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #17098 has been updated by marcandre (Marc-Andre Lafortune). AFAIK, the only way to check for `-0.0` is `1.0 / var == -Float::INFINITY` I find it difficult to discuss what need to be done about any of this as I do not know of the use cases for `-0.0`; without them it seems very theoretical. ---------------------------------------- Bug #17098: Float#negative? reports negative zero as not negative https://bugs.ruby-lang.org/issues/17098#change-86898 * Author: chrisseaton (Chris Seaton) * Status: Open * Priority: Normal * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN ---------------------------------------- Is this intended behaviour? ``` irb(main):001:0> neg_zero = -0.0 => -0.0 irb(main):002:0> neg_zero.negative? => false irb(main):003:0> neg_zero < 0 => false ``` It happens because `Numeric#negative?` uses `< 0`. My understanding of IEEE floating point is that negative zero is not less than zero, but I think it should still report as negative. -- https://bugs.ruby-lang.org/