From: Mark Hahn <mchahn@...>
Date: 2001-12-29T09:29:28+09:00
Subject: [ruby-talk:29606] Re: promoting self to subclass (was extending method of class A ...)

Not at all, which is why I changed the subject.

----- Original Message -----
From: "Tomasz Wegrzanowski" <taw@users.sourceforge.net>
To: "ruby-talk ML" <ruby-talk@ruby-lang.org>
Sent: Friday, December 28, 2001 4:16 PM
Subject: [ruby-talk:29604] Re: promoting self to subclass (was extending
method of class A ...)


> On Sat, Dec 29, 2001 at 01:01:35AM +0100, Mark Hahn wrote:
> > Why not allow a method to "promote" it's object to a subclass of the
object?
> > I've wanted to do this before in ruby and Java.  It should be somewhat
easy
> > in ruby and nearly impossible in a static language.
> >
> > How about making it:  self.promote(Klass)  or maybe
Kernel::promote(Klass) ?
> > The same code that does the promotion could set the extra instance
> > variables.  Or, even better, the initializer of the subclass could be
called
> > with params from the promote call: self = Klass.new(*params).  In
general
> > this could be considered "assignment to self".
> >
> > Where I've run into this need is when an initializer realizes that,
based on
> > input params, there is a more specific class for this data.  Another
case is
> > when an object is created and the "type" gets refined later.  If you
want a
> > specific example of this being used, let me know.
>
> How can it be used in presented Real/Complex case ?
>