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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: subprogram must not be deeper than access type
Date: Sun, 25 Sep 2011 10:23:35 -0400
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2011-09-25T10:23:35-04:00
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Natasha Kerensikova <lithiumcat@gmail.com> writes:

> And GNAT refused to compile it, because "subprogram must not be deeper
> than access type".
>
> So I imagined that since Builder and Output have the same lifetime, it
> might not be so well-define which will cease to exist first.

Note that the error message says "access TYPE".  The Output object
has nothing to do with it.  It is complaining because the access
type is at library level, whereas Builder is nested inside Main.

>...So while
> not strictly deeper, being as deep can be a problem.

No, two things at the same level have lifetimes that end at
the same time.

I don't really understand what you're trying to do, so I can't advise
you how to fix it.  It might be better to use dispatching procedures
rather than access-to-procedure.

It's probably best if you avoid putting any significant code inside
your main procedure.  Put everything in library packages or generic
packages, and make the main procedure just one line.

- Bob