Re: A proposal for formal packages matching

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Mon, 15 Dec 2008 07:43:47 -0800 (PST), Ludovic Brenta wrote:

> The child's body sees its parent's private part but what does that
> have to do with the generic? The generic only needs visibility into
> the parent's public part.

I cannot comment on this. It is not about what a generic child needs. It is
about matching formal packages.

> Assuming the language allowed you to pass a
> child as the actual for a formal that requires a parent, what would
> this buy you?

Simplicity, no need to search for a parent. I don't see any obvious reason
why an instance of a child should not match its formal parent.

> If you see the child (AB) you can also see its parent
> (A) so I can't think of a case where passing the parent as the actual
> is a problem.

The parent can be a formal parameter of a formal parameter of a generic
package that instantiates the child in its declaration part. There existed
problems such constructs before. I cannot tell whether they were Ada 95 or
GNAT problems, and whether one cannot run into similar issues in Ada 2005.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de