From: Justin Collins <justincollins@...>
Date: 2008-04-30T04:03:15+09:00
Subject: Re: Mixins

Marcin Tyman wrote:
> Hi guys!!!
> My question is:
>
>   Is any way to define variables in module which can be further used in
> mixin? The problem is that module I wanted to include into class has
> constant variables defined which are used within function it implements.
> I'm looking for simplest way to overwrite the variables from the class
> (may change the variables to non constant ones) the same meaning not to
> change implementation of functions from the module. See:
>
> module Mod
>  AnyVar = 10
>
>  def func
>    #the method use AnyVar
>  end
> end
>
> class MyClass
>  include Mod
>
>  def initialize
>   #read configuration
>
>   #how to make the function use new AnyVar value without changing its
> implementation and parameters list
>   func()
>  end
> end
>
>
> Thanks a lot for any ideas.
>   

I am not sure I quite understand what you are trying to do, but you can 
do something like this:

module A
        def initialize
                super
                @var = 1
        end
end

class B
        include A

        def initialize
                super
        end

        def check_var
                puts @var
        end
end

B.new.check_var  #=> 1


The trouble is you need to make sure you call 'super' religiously if you 
are including a lot of modules.

-Justin