From: Robert Klemme <shortcutter@...>
Date: 2007-06-08T01:10:10+09:00
Subject: Re: #<Object:0x2c1c8f0> <--- why is the displayed number == object_id*2

On 07.06.2007 17:39, Meinrad Recheis wrote:
> On 6/6/07, Robert Klemme <shortcutter@googlemail.com> wrote:
>> On 06.06.2007 17:10, Meinrad Recheis wrote:
>> > irb(main):001:0> VERSION
>> > => "1.8.5"
>> > irb(main):002:0> o=Object.new
>> > => #<Object:0x2c1c8f0>
>> > irb(main):003:0> ObjectSpace._id2ref 0x2c1c8f0
>> > RangeError: 0x2c1c8f0 is not id value
>> >        from (irb):3:in `_id2ref'
>> >        from (irb):3
>> > irb(main):004:0> ObjectSpace._id2ref 0x2c1c8f0/2
>> > => #<Object:0x2c1c8f0>
>> > irb(main):005:0>
>> >
>> > I think that is pretty confusing. I am sure there is a good reason for
>> > this. But, don't you think it'd be better to display the real
>> > object_id instead of the doubled value?
>>
>> The output of #inspect is not meant to give you any means to get at the
>> original object although it may seem so at times.  Having said that,
>> #object_id and #inspect are completely unrelated and it's just an
>> implementation artifact that some classes actually return something that
>> resembles the object id.
>>
>> As far as I remember this list you are the first one that mentions this.
>>   So it's probably not that big an issue (at least not as confusing as
>> "singleton class" :-))
>>
> Thanks for your answer. I came across it while debugging a running
> application via an eval console. It's not really a problem because I
> know that I need to divide the displayed id by 2 to get the object.

Well, but that won't work for all cases.

> I
> posted it just because ruby didn't work as I expected it to ... which
> is completely against the principles of the language.

That's only one way to look at it.  The other way is of course to assume 
that your expectations were "wrong" (whatever that means).  :-)

Kind regards

	robert