From: Tom Sawyer <transami@...>
Date: 2003-01-24T13:51:12+09:00
Subject: Re: contained_by method (challange)

On Thursday 23 January 2003 04:45 pm, Lyle Johnson wrote:
> Congratulations; so few people reach that point in their life ;)

only if i knew what i knew better! :-)

> > i would like all my objects to have a #contained_by method that returns a
> > reference to the object they are contained by.

> For starters, you need to clarify what you mean by an object
> "containing" another object.
>
> For your first example, you're talking about one object that is a member
> of an Array. For your second example, you're talking about an object
> that is an instance variable of another object. Those are two different
> concepts.

yes, well i figured that #contained_by would have variant meaning dependent on 
the context, but....

> If you just wanted to focus on the first case -- a method that returns a
> list of all the arrays that include the object as an array member -- you
> could use this:
>
>      class Object
>        # Return an array of the arrays that contain me
>        def contained_by
>          containers = []
>          ObjectSpace.each_object(Array) { |anArray|
>            containers << anArray if anArray.include? self
>          }
>          containers
>        end
>      end

quite right. an object can be contained by many another object. hmmm....

> Hope this helps,

very much so. thank you!

-- 
tom sawyer, aka transami
transami@transami.net