[#104004] [Ruby master Feature#17883] Load bundler/setup earlier to make `bundle exec ruby -r` respect Gemfile — mame@...
Issue #17883 has been reported by mame (Yusuke Endoh).
21 messages
2021/05/24
[ruby-core:103787] [Ruby master Bug#17631] `Numeric#real?` incorrectly returns true for `NaN` and `INFINITY`
From:
jtannas@...
Date:
2021-05-11 19:02:26 UTC
List:
ruby-core #103787
Issue #17631 has been updated by jtannas (Joel Tannas). Fair enough - If we're not worrying about following the mathematical definitions too closely then we can gloss over a lot of these details about the definition of "real numbers" and leave it as-is. Instead, how about a new method `#rational?` that responds with a boolean on whether a number will respond successfully to `#rationalize`? - `#rationalize` fails for complex numbers, NaN, and the infinities so `rational?` would give the desired behaviour - it meshes nicely with the existing `Rational` class - it gives users a simple check for if a number is "well behaved" ---------------------------------------- Bug #17631: `Numeric#real?` incorrectly returns true for `NaN` and `INFINITY` https://bugs.ruby-lang.org/issues/17631#change-91900 * Author: jtannas (Joel Tannas) * Status: Open * Priority: Normal * ruby -v: ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN ---------------------------------------- In mathematics, infinity is not a real number. See https://math.stackexchange.com/a/750787 I don't have a source for this, but I also believe that `NaN` is not a real number. `Numeric#real?` incorrectly returns `true` for both of these cases. ``` ruby irb(main):001:0> Float::INFINITY.real? => true irb(main):002:0> Float::NAN.real? => true irb(main):003:0> require 'bigdecimal' => true irb(main):004:0> BigDecimal::NAN.real? => true irb(main):005:0> BigDecimal::INFINITY.real? => true ``` I ran into this while doing some math with logarithms, leading me to have to put in weird catches like `return nil if result.complex? || result.nan? || result.infinite?` --- Originally reported here: https://stackoverflow.com/q/64795265/7950458 -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:[email protected]?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>