Re: Ada Annoyances

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

On 27/06/2017 22:41, Randy Brukardt wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
> news:oit1at$2vo$1@gioia.aioe.org...
>> On 26/06/2017 23:40, Randy Brukardt wrote:
> ...
>>> As I tried to say yesterday, Ada does have a flaw in that allows
>>> dispatching
>>> calls within contructors (and more generally, inside of any primitive
>>> operations). That requires work of some sort, but it is possible, and it
>>> shouldn't be.
>>
>> Hmm, but what are you going to do about Rosen's trick? All use-cases where
>> it is used (to work around language problems, constructors included) must
>> be eliminated first. Only then re-dispatch could (and must) be outlawed.
> 
> Avoid it? I've never used it in actual code, because it never seemed to save
> anything (and it forces using limited types, which I avoid as much as
> possible). I've always used an allocated "real-data-part" in the cases where
> the Rosen trick might have helped.

There are cases where I need it (or a class-wide discriminant similar to 
it):

1. Multiple inheritance emulated by mix-in. There is nothing wrong in 
proper mix-in, but in this case both objects are in fact the same one 
initialized at the same point with all problems following from that.

2. Components of [pointers to] task or protected type, since I cannot 
meaningfully use them via inheritance.

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