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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada Annoyances
Date: Thu, 29 Jun 2017 19:50:11 -0500
Organization: JSA Research & Innovation
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Xref: news.eternal-september.org comp.lang.ada:47200
Date: 2017-06-29T19:50:11-05:00
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"Robert A Duff" <bobduff@TheWorld.com> wrote in message 
news:wcca84q5vq1.fsf@TheWorld.com...
> Niklas Holsti <niklas.holsti@tidorum.invalid> writes:
...
> I agree, I don't see a problem here.  When Finalize is called, it
> dispatches via the currrent Tag.  Tags can't change in Ada, but if they
> could it would still dispatch via the Tag value present when Finalize is
> called.

That's not the problem. The problem is knowing whether to call Finalize at 
all. The only solution I could see for the GNAT approach is to treat all 
tagged objects as controlled (using a null Finalize in cause the object 
isn't controlled). That's expensive.

For a list-based approach (like the one Janus/Ada uses), I don't see any 
solution at all. Putting every tagged object on the finalization lists would 
be prohibitively expensive.

                         Randy.