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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: T'Interface attribute
Date: Wed, 9 Aug 2017 09:06:53 +0200
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Date: 2017-08-09T09:06:53+02:00
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On 2017-08-09 02:38, Randy Brukardt wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message

> We didn't bother. My recollection is that Windows doesn't make a distinction
> anyway, I believe all Windows "windows" can be clicked, just some have
> default actions in that case, and others do nothing.

So you basically drop typing. I don't. There are lots of languages going 
this path. Why use Ada?

> In the long run, it because fairly obvious that the best design was to make
> everything primitive and never use class-wide items anywhere (and only use
> dispatching in call-backs).

Huh, without multiple dispatch this has no chance to work. Anyway 
multiple dispatch does not supersede multiple inheritance.

> Places where we didn't do that we often lived to
> regret and in extreme cases, change (like the Move Window routine, which
> started out class-wide and ended up both -- as we couldn't remove the
> class-wide routine for compatibility reasons).

I agree that there are difficult choices between class-wide and 
primitive. If you make everything primitive you may be hit by 
re-dispatch issues later. However this is more related to alternative 
decomposition methods Ada does not have, e.g. operation extension, 
delegation etc.

Nothing of this can ever eliminate interfaces.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de