Re: I'm facing an issue with: call to abstract procedure must be dispatching

[Serge Robyns <serge.robyns@gmail.com>]

On Tuesday, 8 December 2015 22:55:33 UTC+1, Serge Robyns  wrote:
> On Tuesday, 8 December 2015 22:09:13 UTC+1, Dmitry A. Kazakov  wrote:
> > On Tue, 8 Dec 2015 12:21:31 -0800 (PST), Serge Robyns wrote:
> > 
> > If you really need mix-in then better do it like this:
> > 
> >    type T_Abstract_Data_Store
> >       (  Clients : not null access T_Abstract_Client'Class;
> >          Store2 : not null access T_Abstract_Store2'Class
> >       )  is abstract tagged limited record
> > 
> > This would add a bit more safety, much needed when using access types.
> 

Done, everything is completed and runs.  The tag error was a "hidden" bug where I didn't return the right child class.  Once I got around the issue the changes went quickly through and I would have had only one bug if I had used the above construct immediately as the compiler wouldn't allowed me to "forget".  This is what amazes me with Ada.

Now I've a generic question with regards to access type vs. in-out for parameters.  What is the proper Ada way to pass the "Store" around?
Is it:
Procedure Do_Something (A_Store : in out T_Abstract_Store'Class);
or:
Procedure Do_Something (A_Store : not null access T_Abstract_Store'Class);
?

As a former C programmer my habit goes for the not null access variant.

Regards,
Serge