Re: Problem with protected type

["Randy Brukardt" <randy@rrsoftware.com>]

"Ludovic Brenta" <ludovic.brenta@insalien.org> wrote in message
news:m38ym4xuqq.fsf@insalien.org...
> > And can I create inheritable protected classes?
>
> No.  This has been proposed as an extension to the language [1] back
> in 2000, but the discussions concluded that there was no demand for
> this feature from paying customers, so therefore no compiler vendors
> were going to implement it.
>
> [1] http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00250.TXT?rev=HEAD

That's not quite the right conclusion. Besides the importance question,
there are also technical issues related to locking that are quite difficult
to solve usefully. Moreover, having the code for locking an protected object
in several units could be very difficult to understand and analyze. The ARG
decided to look at protected interfaces instead (that is, provide interface
inheritance, but not implementation inheritance.) That's AI-345. I don't
know if these will be adopted (there are several issues that need to be
resolved), but it looks like a more promising approach than that given in
AI-250.

               Randy Brukardt.