From: Robert Dober <robert.dober@...>
Date: 2010-06-11T14:52:14+09:00
Subject: Re: comparing objects

On Thu, Jun 10, 2010 at 6:48 PM, Mark Abramov <markizko@gmail.com> wrote:
> Robert Dober wrote:
>> On Thu, Jun 10, 2010 at 5:30 PM, Rein Henrichs <reinh@reinh.com> wrote:
>> overwriting #hash and #eql? breaks  Hash!
> That's not true, I think.
Judge for yourself

require "forwardable"

def count klass
  ObjectSpace.each_object( klass ).to_a.size
end
class N
  extend Forwardable
  attr_reader :n
  def_delegators :n,  :hash
  def eql? otha
    n == otha.n
  end
  private
  def initialize n
    @n = n
  end
end # class N


h = { N.new( 42 ) => true }
h[ N.new( 42 ) ] = 42
p h
GC.start
p count(N)

Cheers
R.