From: james.d.masters@...
Date: 2007-03-16T00:25:09+09:00
Subject: Re: General Ruby OOP Question - using inheritance or include for shared attributes

On Mar 15, 12:11 am, "Trans" <transf...@gmail.com> wrote:
>   module X; def self.x; "x"; end; end
>   class Y; include X; end
>   Y.x  #=> error
>
> IMHO It's unfortunate that this is the case --or at least that there's
> not a method other than #include that can do it. I guess it's because
> I wrote annotations, which turned out to be very tricky b/c of this.

In the case of pulling in module methods as class (singleton) methods,
you can use extend instead of include.  Your second example rewritten
with "extend" would work:

module X; def x; "x"; end; end
class Y; extend X; end
Y.x  #=> "x"

Unfortunately, I'm fairly sure that would require separate modules for
class methods (through extend) and instance methods (through include).