From: Art Gillespie <agillesp@...>
Date: 2005-10-08T05:30:54+09:00
Subject: Re: newb: Class Method determining it's actual class?

Hi again,

There must be some law somewhere says that the chances of finding the
answer yourself goes up exponentially in the moments after posting to
a mailing list.

I hadn't even thought to try 'self' in a class method.  Much to learn.

Thanks again,

Art

On 10/7/05, Art Gillespie <agillesp@gmail.com> wrote:
> Hi,
>
> New to Ruby and to the list.  I've looked through pickaxe and through
> the ruby source code and haven't figured this one out.
>
> With the built-in File class, if I derive from it and call a class
> method (e.g., open) what I get back is an instance of my derived
> class:
>
> class IFFFile < File
> end
>
> f = IFFFile.open("media.iff", "r")
>
> f.class => "IFFFile"
>
> How does one do this with their own class methods?
>
> class A
>   def A.open
>     #how do we know here if the message recipient is a subclass of A?
>     #i.e., can't we generalize it so that it is, in effect, class.new?
>     A.new
>   end
> end
>
> Many thanks for any pointers to what I'm missing.
>
> Art
>
>