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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Constructing an object
Date: 30 Sep 2005 13:49:04 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2005-09-30T13:49:04-04:00
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"Randy Brukardt" <randy@rrsoftware.com> writes:

> Ah, I see. Certainly you are right here. I see that a lot in Finalize
> routines; it is real easy to forget to call the Finalize for the parent
> type. There ought to be a better way of extending rather than replacing
> routines; that's especially true since requires an explicit type conversion
> to the parent to make that call, and it is easy to get wrong (and go
> infinitely recursive).

The Common Lisp Object System has such a feature.  You can declare
methods that are called in addition to the parent's version (either
before or after) rather than the more common feature of calling them
instead of the parent's version.  And I think there's a feature for
declaring a method that must call the parent's version somewhere within
it -- or something like that.

If such additional complexity were to be added to Ada (I doubt it!),
it would be a shame to make it work just for Initialize/Finalize.
It really should be a general purpose feature.  This need (where an
overriding "should" call the parent) comes up a lot in OO code;
Finalize is just a special case.

- Bob