From: Adam Prescott <mentionuse@...>
Date: 2010-09-15T05:00:04+09:00
Subject: Re: Extend & Declarative relations between object attributes

Extend is include on the eigenclass/metaclass/singleton class. In this
case, it's like saying

C.extend Observable

because of the implied "self".

On Tue, Sep 14, 2010 at 8:52 PM, Ralph Shnelvar <ralphs@dos32.com> wrote:
> Sunday, September 12, 2010, 6:19:53 PM, you wrote:
>
> JV> # Let's just include Observable globally. Conservatively, one would do:
> JV> #
> JV> #   class C
> JV> #     extend Observable
> JV> #     include Observable::Match   # if desired
> JV> #     ...
> JV> #   end
>
> I give.  What does
>  extend Observable
> do?
>
> I see in Dave Thomas' *Programming Ruby 1.9* that extend "Adds to obj the instance methods from each module given as a parameter".
>
> So ... what object is "extend Observable" referring to?  The class C object? (That is, the class that is C rather than the instance that is C.)  Is this related to some singleton stuff?
>
> And how is the extend different than the include?
>
>
> Ralph