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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Inherited Methods and such
Date: Sat, 29 Sep 2007 19:39:47 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2007-09-29T19:39:47-04:00
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Maciej Sobczak <see.my.homepage@gmail.com> writes:

> On 28 Wrz, 22:44, Maciej Sobczak <see.my.homep...@gmail.com> wrote:
>
>> Yes, this example is convincing.
>
> After thinking about it for a while, I see one point missing:
> accessing T'Class from the supertype (T's) constructor. I need it to
> register the new object in the polymorphic container.

You can convert the result object to T'Class.
You can create an access-to-T'Class value.
I don't see the problem.

But if you dispatch "too early", things can get confusing.

One limitation of my example: it doesn't work if the parent
type is abstract.  In a from-scratch language design, I think
I would solve that problem by allowing the creation of objects
of abstract type.  And constructor functions returns such
objects.  But don't allow conversion of such objects to
class-wide (to avoid dispatching (to abstract subprograms)).
What do you think about that?  It's not Ada, of course.

- Bob