From: chris@chrisseaton.com
To: ruby-core@ruby-lang.org
Subject: [ruby-core:99441] [Ruby master Bug#17098] Float#negative? reports negative zero as not negative
Date: Sat, 01 Aug 2020 16:00:52 +0000 (UTC)
Message-ID: <redmine.journal-86896.20200801160052.8671@ruby-lang.org> (raw)
In-Reply-To: <redmine.issue-17098.20200801010523.8671@ruby-lang.org>
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/
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Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-01 1:05 [ruby-core:99426] " chris
2020-08-01 2:18 ` [ruby-core:99427] " merch-redmine
2020-08-01 12:18 ` [ruby-core:99432] " chris
2020-08-01 12:38 ` [ruby-core:99433] " sawadatsuyoshi
2020-08-01 12:50 ` [ruby-core:99434] " chris
2020-08-01 16:00 ` chris [this message]
2020-08-01 18:02 ` [ruby-core:99442] " eregontp
2020-08-01 19:41 ` [ruby-core:99443] " marcandre-ruby-core
2020-08-02 12:21 ` [ruby-core:99444] " sawadatsuyoshi
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