From: Daniel Berger <djberg96@...>
Date: 2006-05-14T07:03:53+09:00
Subject: Re: Using alias_method in mixin module

Justin Collins wrote:
> Hi all,
> 
> I have a mixin module that needs to redefine a particular method if it 
> already exists and retain a reference to it for later use. This is what 
> I came up with:
> 
> module Example
> 
>        def Example.included(klass)
>                if klass.instance_methods.include? "look_inside"
>                        klass.instance_eval { alias_method 
> :old_look_inside, :look_inside }
>                        klass.send(:define_method, :look_inside) { |event|
>                            #use old_look_inside in here
>                        }
>                end
>        end
> 
> end
> 
> 
> Is there a better/different way of doing this? (This works, I'm just 
> curious).

I'd say you should alias the module's method, not the original class' 
method, because otherwise class hierarchy issues could get confusing. 
How should a subclass behave, for example?

Anyway, I wrote the 'use' package specifically to deal with this situation:

class Foo
    include Example, :alias => {:look_inside, :example_look_inside}
end

Your other option is to adopt a simple naming convention for your 
modules, where all methods from the Example module start with 'example_' 
(for example), and avoid the entire issue altogether.

Regards,

Dan