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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Dereferencing and style guides
Date: Fri, 18 Oct 2013 21:46:31 -0500
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2013-10-18T21:46:31-05:00
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"Robert A Duff" <bobduff@shell01.TheWorld.com> wrote in message 
news:wcc8uy0t1ec.fsf@shell01.TheWorld.com...
...
> By "dereference fails", I assume you're talking about null pointers.
> I wasn't so worried about that -- I'm more worried about
> aliasing.  I'm thinking "X^.Y := ..." is a helpful reminder that
> some other pointers might also point to X^.

Besides my other reply, I don't buy this anyway. If X is a parameter, it 
might have other aliases around whether or not it is a pointer (certainly, 
for anything that could be passed by reference). And even if not a parameter 
X, can be aliased by foreign code, chapter 13 stuff, etc.

The moral is, if you worry about potential aliasing, you're just going to 
drive yourself nuts (or be seriously oversimplifying). Aliasing in Ada 
really depends on the type of a name: if it has an elementary type, it's OK 
to assume that it isn't aliased; otherwise, you have to assume that it can 
be. Dereferences are irrelevant to that calculation, so I don't see much 
point in emphasizing them.

                                                  Randy.