From: Brian Candler <b.candler@...>
Date: 2008-12-14T20:16:43+09:00
Subject: Re: singleton methods vs. meta instance methods

Robert Dober wrote:
> On Sat, Dec 13, 2008 at 10:50 PM, Brian Candler <b.candler@pobox.com> 
> wrote:
>> Robert Dober wrote:
>>> I could however not see the difference between A and Object, can you
>>> explain please?
>>
>> The OP used an *instance* of class Object, not Object itself, and
>> compared it with class A, which is an instance of class Class.
> Brian I referred to exactly the same thing you do in your next post,
> just do a %s/Object/String/g.

Maybe I overlooked something - all these classes and metaclasses can get 
pretty confusing :-) I was comparing the part of your code where you 
wrote:

def Object.answer; 42 end

with the OP's which had:

obj = Object.new
def obj.foobar; end

> No really I feel up to here we are just fine, the problem starts when
> we define something in the metaclass and
> see it in the singleton class

I'm not sure what the distinction is you're trying to make between 
metaclass and singleton class. I believe they are two names for the same 
thing.

The OP was trying to demonstrate that "an object's singleton methods are 
defined as the instance methods of that object's meta/singleton class"

This was demonstrated successfully, given the additional info that 
metaclass.instance_methods(false) returns both the instance methods in 
the metaclass plus the instance methods of the actual class.

However, obj.singleton_methods returns only the instance methods in 
obj.metaclass.

At least, that's how I understand it at the moment - I am happy to be 
corrected if this is wrong.
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