From: Robert Klemme <shortcutter@...>
Date: 2010-11-11T17:35:15+09:00
Subject: Re: what's an object?

On Thu, Nov 11, 2010 at 5:25 AM, Y. NOBUOKA <nobuoka@r-definition.com> wrote:
>> Simple answer:  everything.  Everything is considered an object,
>> including an instance of a class, the class itself, its methods, etc.
>
> There is one thing incorrect.
> In Ruby, an instance of a class or a class itself is exactly an object,
> while a method is NOT an object.
>
> Although we can obtain a Method object using the *Object#method*
> method [ http://ruby-doc.org/core/classes/Object.html#M000336 ], a
> method itself is not an object.

I suggest a modification of Alex's definition:

Everything /which can be referenced through a variable/ is considered an object.

This includes classes, instances of Method etc.  It's just that Method
and subclasses are basically only proxies to the underlying
implementation of a method - with limited functionality (obtaining
arity and executing them for example).  The mere fact that we obtain a
new instance whenever we invoke #method hints at this:

irb(main):005:0> s=""; 2.times.map { s.method(:length).object_id }
=> [134981756, 134981742]

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/