From: Michael Edgar <adgar@...>
Date: 2011-09-07T03:08:11+09:00
Subject: [ruby-core:39307] Re: [Ruby 1.9 - Bug #5285] Ruby 1.9.2 throws exception on sort of array containing true AND false values

Booleans are not ordered. It doesn't make sense to say "the logical value true is less than/greater than the logical value false" - that statement doesn't mean anything. I can't help but feel sorting an enumerable of booleans is a nonsensical operation. I'm not even sure what purpose it would serve that wouldn't more reasonably be modeled by another (likely more efficient) operation.



On Sep 6, 2011, at 1:30 PM, Pedro Medeiros <pedrosnk@gmail.com> wrote:

> 
> Issue #5285 has been updated by Pedro Medeiros.
> 
> 
> actually, by doing true <=> false on irb returns nil, while doing true <=> true or false <=> false will return 0. not necessarily an exception. Wouldn't it be right to return -1 or 1 by comparing true with false or false with true, even though true came from TrueClass and false came from FalseClass ?
> ----------------------------------------
> Bug #5285: Ruby 1.9.2 throws exception on sort of array containing true AND false values
> http://redmine.ruby-lang.org/issues/5285
> 
> Author: Martin Corino
> Status: Rejected
> Priority: Normal
> Assignee: 
> Category: core
> Target version: 1.9.2
> ruby -v: ruby 1.9.2p290 (2011-07-09 revision 32553) [x86_64-linux]
> 
> 
> I encountered a very weird bug.
> 
> Sorting of arrays containing identical boolean values (ALL true or ALL false) works fine.
> As soon as 1 value differs however #sort throws an exception.
> 
> 
> ruby-1.9.2-p290 :001 > [true, true].sort
> => [true, true] 
> 
> ruby-1.9.2-p290 :002 > [false, false].sort
> => [false, false] 
> 
> ruby-1.9.2-p290 :003 > [false, true].sort
> ArgumentError: comparison of FalseClass with true failed
>        from (irb):3:in `sort'
>        from (irb):3
>        from /home/martin/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `<main>'
> 
> ruby-1.9.2-p290 :004 > [false, true, false].sort
> ArgumentError: comparison of FalseClass with true failed
>        from (irb):4:in `sort'
>        from (irb):4
>        from /home/martin/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `<main>'
> 
> ruby-1.9.2-p290 :011 > [true, true, true, true].sort
> => [true, true, true, true] 
> 
> ruby-1.9.2-p290 :012 > [true, true, true, false].sort
> ArgumentError: comparison of TrueClass with false failed
>        from (irb):12:in `sort'
>        from (irb):12
>        from /home/martin/.rvm/rubies/ruby-1.9.2-p290/bin/irb:16:in `<main>'
> 
> 
> 
> -- 
> http://redmine.ruby-lang.org
>