From: Marc-Andre Lafortune <ruby-core-mailing-list@...>
Date: 2011-09-16T15:31:25+09:00
Subject: [ruby-core:39576] Re: [Ruby 1.9 - Bug #4576] Range#step miss the last value, if end-exclusive and has float number

Hi,

On Thu, Sep 15, 2011 at 8:57 PM, Kenta Murata <muraken@gmail.com> wrote:
> I cannot find tests for the commit r33282. Please tell me where the tests are.
> If you write the tests in RubySpec, please describe the commit hashes of the corresponding
> commits of RubySpec in the commit message of the commit of CRuby.

Good idea, I'll include the commit hash in future commits, with the
format [rubyspec:a9525edcd], unless there is another suggestion.

Note that the RubySpec is easy to find, either with `git log
--grep=4576` or `grep -r 4576 .`, or looking up the path of the
modified method(s) (here core/range/step_spec.rb). The hash in the
commit will be an additional way.

>> Would it be ok if `Float("3.0e-31").to_s == "3.0000000000000003e-31"`?
>
> I've objected to the behavior. Please look at the rejected my report.
> http://redmine.ruby-lang.org/issues/4656

Actually, in my example, 3.0e-31 != 3.0000000000000003e-31.

As for why up to 17 decimals may be needed to represent a float, see
my original issue #3273, or
http://en.wikipedia.org/wiki/IEEE_754-2008#Character_representation