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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Pop function
Date: Thu, 15 Dec 2011 18:31:24 -0600
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2011-12-15T18:31:24-06:00
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"Jeffrey Carter" <spam.jrcarter.not@spam.not.acm.org> wrote in message 
news:jcdjfs$atd$1@adenine.netfront.net...
...
> No, a public interface should never use access types, ever. Hiding those 
> is what abstraction is about. Any public interface that uses access types 
> is poorly designed.

Geee, even I wouldn't go quite *that* far. There are some cases where you 
have to have reference semantics (the "Parent" function in Claw is an 
example), and in those cases ONLY it might make sense to visibly use an 
access type.

Ada 2012 provides "aliased" parameters to force reference semantics, and 
it's possible to encapsulate the access type so that it can't be abused, so 
this can actually be done safely. But that is an advanced topic.

                                               Randy.