From: Yui NARUSE <naruse@...>
Date: 2011-09-16T16:18:59+09:00
Subject: [ruby-core:39579] [Ruby 1.9 - Bug #4576] Range#step miss the last value, if end-exclusive and has float number


Issue #4576 has been updated by Yui NARUSE.


 Marc-Andre Lafortune wrote:
> I re-committed as r33285 because
>  * Ruby should not keep it platform dependent with default compile
>  flags [ruby-core:39566], [ruby-core:28212]
>  * this commit has corresponding test [rubyspec:a9525edcd]

Such style doesn't get consensus over the thread [ruby-core:39260].

>  Before reverting a commit, please give an example of a problem it can
>  cause or provide a failing test.
>  
>  It a commit doesn't address all the possible scenarios, please re-open
>  the issue so additional patches can be made.

See following results, it includes your ruby and RubySpec change:
http://u32.rubyci.org/~chkbuild/ruby-trunk/log/20110915T230102Z.log.html.gz
http://u64.rubyci.org/~chkbuild/ruby-trunk/log/20110915T230102Z.log.html.gz
http://c5632.rubyci.org/~chkbuild/ruby-trunk/log/20110915T230102Z.log.html.gz
http://c5664.rubyci.org/~chkbuild/ruby-trunk/log/20110915T230301Z.log.html.gz
http://www.rubyist.net/~akr/chkbuild/debian/ruby-trunk/log/20110916T000500Z.log.html.gz

Now I doubt your understanding of floating point number, so please learn it and check your understanding
before recommit it.
----------------------------------------
Bug #4576: Range#step miss the last value, if end-exclusive and has float number
http://redmine.ruby-lang.org/issues/4576

Author: Joey Zhou
Status: Closed
Priority: Normal
Assignee: 
Category: core
Target version: 1.9.4
ruby -v: -


=begin
Hi, I find that:

* if: range.exclude_end? == true
* and: any one in [begin_obj, end_obj, step] is a true Float(f.to_i != f)
* and: unless begin_obj + step*int == end_obj
* then: the result will miss the last value.

for example:

 p (1...6.3).step.to_a # => [1.0, 2.0, 3.0, 4.0, 5.0], no 6.0
 p (1.1...6).step.to_a # => [1.1, 2.1, 3.1, 4.1], no 5.1
 p (1...6).step(1.1).to_a # => [1.0, 2.1, 3.2, 4.300000000000001], no 5.4

 p (1.0...6.6).step(1.9).to_a # => [1.0, 2.9], no 4.8
 p (1.0...6.7).step(1.9).to_a # => [1.0, 2.9, 4.8]
 p (1.0...6.8).step(1.9).to_a # => [1.0, 2.9, 4.8], no 6.7

Maybe the #step is ok on integers, but there's something wrong if the range is end-exclusive and contain float numbers.
=end



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