From: Bernd Burnt <djbearhand@...>
Date: 2007-05-12T00:30:00+09:00
Subject: Re: Is there a possibility to include methods of a class?

Brian Candler wrote:
> On Fri, May 11, 2007 at 10:29:01PM +0900, Bernd wrote:
>> Hi all,
>> first of all: this list and you rock! I know that there is no multiple
>> inheritance, but you can use the concept of mixin.
>> However, I want to inherit my class another and "mixin" methods from
>> another class.
>> To be more precise,
>> I have a class that inherits another one (that comes from a library and
>> I do not want to change) and I want the methods of ActiveRecord::Base in
>> my class. Is there a way to do that (without copying and paste the whole
>> ActiveRecord::Base class and changing it to a module)?
> 
> I would use delegation for one class or the other.
> 
> That is: define your class as
> 
> class Foo < ActiveRecord::Base
>   ..
>   def initialize
>     @other = Library::Bar.new
>   end
> end
> 
> Or vice versa, whichever makes more sense. And if you can't choose, then
> delegate to both.
> 
> class FooDB < ActiveRecord::Base
>   .. more stuff
> end
> 
> class Foo
>   def initialize(id)
>     @db = FooDB.find(id)
>     @lib = Library::Bar.new
>   end
> end
> 
> Then the interface that Foo exposes to the world can pass some calls to 
> @db,
> some to @lib, or (the best news) can combine behaviours from both in
> whichever way it likes.

This is the workaround I just had so far, and now I want to get rid of 
it.

I have two classes:
class Myclass < ActiveRecord::Base
def self.find(number)
  Anotherclass.find(number)
end

class Anotherclass < SAP4Rails::Base
def self.find(number)
  do something
end

But this solution to me seems to be so un-ruby!

As SAP4Rails::Base does not have an explicit superclass, I wondered, if 
there is some way to inject it dynamically a super class, because I need 
some other methods from ActiveRecord in another application
I know that I could just alter the SAP4Rails class, but I want it in the 
way, that you just need ActiveRecord, SAP4RAils and my piece of code.

-- 
Posted via http://www.ruby-forum.com/.