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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Generic Zero Length Array
Date: Mon, 25 Feb 2008 14:14:49 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2008-02-25T14:14:49-05:00
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Adam Beneschan <adam@irvine.com> writes:

> On Feb 23, 6:27 am, Robert A Duff <bobd...@shell01.TheWorld.com>
> wrote:
>>
>> >...I don't think we need "null record" (i.e. in
>> > aggregates) any more either, although certainly nobody is going to
>> > suggest removing it.
>>
>> Why don't we need that?
>
> Because if Rec_Type is a record with no components, Rec_Type'(others
> => <>) will work (and has the same effect as (null record)).

Ah, I see what you mean.

I still want "null record", because it means something different from
"others".  The "null record" means I assert that there are no
components, and please slap me with a compile-time error if
that's not true (or no longer true).  The "others" means that
I want all components to be default-initialized, including
all the ones that have not yet been invented.

If somebody changes "type T is null record" to
"type T is record Blah : Integer; end record;"
I want an error on all the (null record) aggregates.

> Or is there some more complex cases where the "null record" syntax is
> still needed in aggregates?

No.

- Bob