From: Stu <stu@...>
Date: 2012-04-11T11:33:46+09:00
Subject: Re: A Beginner's Question about Metaprogramming

On Tue, Apr 10, 2012 at 7:15 PM, Phil Stone <lists@ruby-forum.com> wrote:
> Thanks, but what does this whole line mean?:
>
> def self.metaclass; class << self; self; end; end
>
> If I am correct, this is defining a Class method named metaclass, which
> has a method named self...? Please elaborate.
>
> --
> Posted via http://www.ruby-forum.com/.
>

It returns self which in this case is a singleton class  called
metaclass which also is a metaclass. It would confuse me also. class
<< self is shorthand for opening up the current class. to make things
worse you can open up metaclasses inside metaclasses.

Look at my example and run these commands:

MyClass.singleton_class
MyClass.singleton_methods

Basically these are just hidden classes which can be used for
exercising the code.

If your really interested in the subject I found metaprogramming ruby
(book) to be a very interesting read.