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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: pointers and genericity
Date: 16 Feb 2005 10:00:12 -0500
Organization: The World Public Access UNIX, Brookline, MA
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Date: 2005-02-16T10:00:12-05:00
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xavier.serrand@free.fr (Xavier Serrand) writes:

> ==============Error messages for source file:
> test/test_gen_pk_user.adb
>     30.          U.Rec.Next := Proc_Suiv'access;
>                                |
>         >>> access type must not be outside generic body

If the access type is outside the generic body, then it's illegal
to take 'Access of a procedure declared inside the generic body.
The workaround is to declare the procedure in the generic
package spec.  If you don't want to export it, put it in
the private part.

I think the reason for this rule has something to do with making it
easier to implement code sharing of generic bodies.

I didn't look at your code carefully, but sometimes it's cleaner to use
a tagged type with a dispatching procedure, rather than an
access-to-procedure, because then you can easily package up
some data with the procedure.

- Bob