From: Maciej Tomaka <lunatyq@...>
Date: 2008-09-02T02:41:37+09:00
Subject: Re: included() vs extended()


> So my question is: given that extend() is implemented (I think) using
> metclass.include(), and that the end result of both is identical, how 
> come
> Hooks.included is not called when using extend()? It seems reasonable 
> that
> both the included() and extended() hooks should be called in this 
> situation,
> though I can just as well see the argument against doing this. Anyone 
> care
> to enlighten/persuade me as to why this behaviour exists?

In ruby everything is an object. So even class is an object.
Still we have extend and include which are not the same methods:

include => includes code into class.

extend  => extends using module, appends class methods.

bar = Bar.new

bar            - object of class Bar
bar.class      - class of object bar
Bar            - class Bar, object of class Class
Bar.metaclass  - class of class Bar :)

Bar.metaclass.send(:include, Hooks)

is called on class of class Bar. So you got the methods as instance 
methods of class Bar.

My explaination may not have sense for you. Better read Why’s Poignant 
Guide to Ruby - chapter 6 and/or Dr. Nic Williams PDF from euruko 
conference http://www.euruko2008.org/pages/show/2-program.

Best Regards

Maciej
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