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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: little precision about anonymous access types
Date: Thu, 17 May 2018 16:17:04 -0500
Organization: JSA Research & Innovation
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Xref: reader02.eternal-september.org comp.lang.ada:52407
Date: 2018-05-17T16:17:04-05:00
List-Id: <comp.lang.ada>

"Mehdi Saada" <00120260a@gmail.com> wrote in message 
news:d294e4a5-864c-4ab0-bf60-6c9a94ace651@googlegroups.com...
> So if it was you, you would have treated subprograms with
>access types parameters as primitives, as long as they are declared
>in the same immediate scope ? It sounds simple, why hasn't it be
>do that way ?

No, I wouldn't bother with dispatching on access values at all. Since Ada 
passes all tagged objects by reference, and 'Unchecked_Access is always 
allowed on tagged parameters, it's always possible to get an access to a 
tagged parameter if that is needed. There's no reason to *pass* that value - 
just pass the tagged object.

Essentially, there's no implementation difference (ignoring the abomination 
of dynamic accessibility) between "access T" and "in out T" for a tagged 
type T. So the former is not really needed - at best it saves 4 characters 
on calls (".all"), but in many circumstances it adds complication (needing 
to add "aliased" and "'Access" in various places).

                   Randy.