From: Robert Klemme <shortcutter@...>
Date: 2008-02-13T06:54:55+09:00
Subject: Re: How to add a instance variable through a mixin?

On 12.02.2008 20:54, MrBanabas@googlemail.com wrote:
>> If you mix the module in after some instances of MyClass have already
>> been created, do you want it to dynamically create the instance
>> variables in those instances?
>>
>> If you mix the module in before some instances of MyClass have been
>> created, do you want it to run code each time a new instance is
>> created?
> 
> I would be interested in both cases, but for my particularly case it s
> the second one.

You can do

module Foo
   attr_accessor :var

   def initialize(*a,&b)
     @var = 10
   end
end

And then

irb(main):015:0> class Bar
irb(main):016:1>   include Foo
irb(main):017:1> end
=> Bar
irb(main):018:0> Bar.new.var
=> 10

Or

irb(main):026:0> class Oink
irb(main):027:1>   include Foo
irb(main):028:1>   def initialize
irb(main):029:2>     super
irb(main):030:2>     @x = 10
irb(main):031:2>   end
irb(main):032:1> end
=> nil
irb(main):033:0> Oink.new.var
=> 10

Kind regards

	robert