From: Kent Dahl <kentda@...>
Date: 2002-01-21T00:34:10+09:00
Subject: Re: Mixin question

Markus Jais wrote:
> class Cla
>     class << self
>         include Mod
>     end
> end
> 
> and
> 
> class Cla
>    extend Mod
> end

No difference, as you've noticed, except the latter looks better IMHO.

Jumping around eval.c (for 1.6.5), you'll notice that the extend call
eventually lands at this code:

<SNIP>
void
rb_extend_object(obj, module)
    VALUE obj, module;
{
    rb_include_module(rb_singleton_class(obj), module);
}
</SNIP>

.... which basically translates into what you do in the first version,
but in C.


-- 
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