Re: Ada Annoyances

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

On 2017-06-26 15:24, Maciej Sobczak wrote:
>> The example must demonstrate dispatch to the operation of the object's
>> type (the ultimate type) from a body defined for the parent type T class.
> 
> Since the Derived object is constructed in a two-step process, the
> useObject function is called twice, once from the Base part and once
> from the Derived part.

Exactly my point. Dispatch is "killed" or misrouted if you want.

>> It is apples and oranges.
> 
> If you choose so. In this particular context, apples taste better.

Yes, if type-specific constructors is what is needed. Ada's concept of T 
and T'Class does not prevent having them, if ARG once decides to fix the 
mess. C++ model cannot be fixed ever.

>> As I explained C++ has type-specific
>> constructors while Ada's Initialization is a class-wide constructor. You
>> cannot compare them.
> 
> I can and I should, since both are used to achieve the same
> design-level intent, which is construction of a newly created object.

No. Application is very different. A class-wide constructor is called 
when construction of all instances is complete. E.g. for T'Class it 
would mean that the specific constructors from T to S are all through.

As I explained the sequence is this:

    T
    S
    S'Class
           / Here the run-time activates a task component of T with
           \ a discriminant of T'Class
    T'Class <- Here you call a task entry to pass parameters

And for destructor:

    T'Class < Here you call an entry to ask task to quit
            < Here the run-time awaits task termination
    S'Class
    S
    T

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