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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Surprise in array concatenation
Date: 05 Sep 2005 19:52:11 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2005-09-05T19:52:11-04:00
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Jean-Pierre Rosen <rosen@adalog.fr> writes:

> Robert A Duff a �crit :
> > Why would you want an unconstrained array indexed by enumeration type?
> > And why would you want an empty array if the array type is constrained?
> >
> I do that all the time, especially in ASIS programming. You may have
> arrays indexed with subranges of declaration_kinds for example.

Really?  I can see why you might have:

    type Declaration_Kind is (This, That, Mumble, Dumble);
    subtype My_Kind is Declaration_Kind range This..That;
    subtype Your_Kind is Declaration_Kind range Mumble..Dumble;

    type A1 is array(My_Kind) of Blah;
    type A2 is array(Your_Kind) of Glorp;

But do you really do this:

    type A is array(Declaration_Kind range <>) of Something;
    subtype A1 is A(My_Kind);
    subtype A2 is A(Your_Kind);

"all the time"?  Nothing wrong with it; I just think the former case
would be by far more common.

And do you create *empty* arrays indexed by enums?  All the time?  ;-)

My empty arrays are usually indexed by signed integer types.

- Bob