From: dblack@...
Date: 2002-11-11T00:13:42+09:00
Subject: Re: return MyClass.new vs self.type.send :new

Hi --

On Mon, 11 Nov 2002, ahoward wrote:

> On Sun, 10 Nov 2002, Brian Candler wrote:
>
> > You can't just create an instance of the base class using the base class's
> > constructor and just 'flip' the type to be SubClass; that would leave the
> > subclass's extra instance variables uninitialised, potentially giving you an
> > invalid object instance.
> [snip]
>
> you *can* if you design it that way :
>
>   module ParentMethods
>     def ParentMethods.extend_object anObject
>       ...
>       do_the_right_thing    # tricky

What is the right thing?

>       ...
>     end
>     ...
>     ...
>     ...
>   end
>
>   class Parent
>     include ParentMethods
>
>     def Parent.bless anObject
>       ParentMethods.extend_object anObject.clone
>     end
>   end
>
>   object_as_parent = Parent.bless object

I'm lost.  Can you explain what you're trying to do?  I'm willing
to go out on a limb and speculate that there's a more idiomatic
(and 'bless'-less :-) way to do it.  But first I need a handle on
what "it" is :-)


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav