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=-4.0 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 B75241F5AE for ; Sat, 1 Aug 2020 16:00:59 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id 72E1C1209A5; Sun, 2 Aug 2020 01:00:26 +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 ABED7120959 for ; Sun, 2 Aug 2020 01:00:24 +0900 (JST) Received: by filterdrecv-p3mdw1-7ff865655c-vtsg9 with SMTP id filterdrecv-p3mdw1-7ff865655c-vtsg9-19-5F2591B4-C3 2020-08-01 16:00:52.557176224 +0000 UTC m=+251073.077365302 Received: from herokuapp.com (unknown) by ismtpd0054p1iad1.sendgrid.net (SG) with ESMTP id fD2gt730RTGun6RAD-o8OQ for ; Sat, 01 Aug 2020 16:00:52.447 +0000 (UTC) Date: Sat, 01 Aug 2020 16:00:52 +0000 (UTC) From: chris@chrisseaton.com Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 75270 X-Redmine-Project: ruby-master X-Redmine-Issue-Tracker: Bug X-Redmine-Issue-Id: 17098 X-Redmine-Issue-Author: chrisseaton X-Redmine-Sender: chrisseaton 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?NC3uwXThXFpCxeI+EU+QkxuM4rZrp+UkiX2tCBF1HHupkeeddVHCRa+5J7lEg5?= =?us-ascii?Q?KwbAFhk3qaQHCmXp1jj+ecij+Jqglkl0m0Cb+bt?= =?us-ascii?Q?3VM0M2bEeKgAbadGmW6V09+WwbAKhqvG0cRX0dy?= =?us-ascii?Q?UZfCC7Qdp2CdgIflt8uvKHxNxeeAqB1eQaZubLe?= =?us-ascii?Q?igEYicJfsxcN=2FZQ+bb11LCDKyH1qrYN41rWhUPn?= =?us-ascii?Q?66L+q8Gs3pb9J5ggs=3D?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 99441 Subject: [ruby-core:99441] [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 chrisseaton (Chris Seaton). If people aren't keen on changing `Float#negative?` since it has existing semantics, then another option could be to add a new predicate `Float#negative_zero?` - that would allow people to differentiate as needed. ---------------------------------------- Bug #17098: Float#negative? reports negative zero as not negative https://bugs.ruby-lang.org/issues/17098#change-86896 * 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/