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From: "Vladimir Olensky" <vladimir_olensky@yahoo.com>
Subject: Re: Ada GC (was Re: Ammo-zilla)
Date: 1999/11/10
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Date: 1999-11-10T00:00:00+00:00
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Robert A Duff wrote in message ...
>Bugs are not caused by people *trying* to do something -- they happen by
>accident!


Yes, no doubt that they happen by accident.

But sometimes they happen when someone  is trying  to do something
using unsafe features to achieve some goal that could not be achieved
using safe features and then something slips out of control (accidentally) .
And this happens not only in programming.

As far as access types concerned probability of such bugs could be
reduced if it would be possible to extend applicability of the VALID
attribute
to be used with some of the access types objects  (not all but at least for
some kind of  "TRACED" ACCESS TYPES  supported  by storage pools
with additional management overhead :-).

I feel that this could be very useful and it could make the idea behind
VALID
attribute to be more complete and more in line with the overall Ada
ideology.

Of course the same goal could be done by putting additional restrictions on
usage of some  unsafe features  but this idea leads to the direction that
were
followed by some other languages .
I feel that the better way (for general purpose programming)  is  to expand
applicability of the existing Ada safety features (making them more
complete).
VALID attribute falls in this category.

I am not insisting on all of that. I am just contemplating.


Regards,
Vladimir Olensky