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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Why both "with" and "use"?
Date: 1999/02/14
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Date: 1999-02-14T00:00:00+00:00
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tmoran@bix.com (Tom Moran) writes:

> alternatively, you could do
>  package Digitizers is
>    type ID is range 1 .. 2;
>    ...
> end Digitizers;
> with Digitizers;
> ...
>   Digitizer : Digitizers.ID;
> which would leave out the Use clause, let the compiler help make sure
> the naming is right, and let the maintainer or simple minded source
> code tool easily spot the origin of Digitizers.ID.

This won't work, because you need the types to be separate from the
Digitizers package.  The organization looks something like this:

with Digitizer_Id_Types; use Digitizer_Id_Types;

package Digitizers is

  procedure Set_Mode (Id : in Digitizer_Id);

...

end Digitizers;


There are clients of Digitizer_Id who are not clients of Digitizers, and
they have to be protected from the volatility of the Digitizers package,
or you end up recompiling the universe every day.