From: Mark Hubbart <discord@...>
Date: 2004-05-29T07:04:55+09:00
Subject: Re: Can an inner class get its container at runtime?


On May 28, 2004, at 1:33 PM, Francis Hwang wrote:

> Is there a way for an inner class to find out what class owns it? The
> code I'd like to use looks like:
>
> class AbstractInnerClass
>   def do_something
>     # here's where I need to find the owner of the concrete child
>   end
> end
>
> class OuterClass
>   class ConcreteInnerClass < AbstractInnerClass
>   end
> end
>
> I'd love to be able to call ConcreteInnerClass#do_something and know
> that it can find OuterClass. Is there a way for me to do this?

Maybe like this?

   class AIC
     def my_container_class
       Object.const_get self.class.to_s.split(/::/)[0...-1].join("::")
     end
   end
     ==>nil
   class Out
     class In < AIC
     end
   end
     ==>nil
   Out::In.new.my_container_class
     ==>Out

This will give an error if there is no outer class, but you should be 
able to wrap the core code line in a begin...rescue block and/or check 
the string to ensure non-emptyness before calling Object.const_get with 
it.

HTH,
Mark