Re: A bad counterintuitive behaviour of Ada about OO

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

On Thu, 7 Aug 2014 00:41:08 -0700 (PDT), Maciej Sobczak wrote:

>> Remember that OO features in practically all OOPL are broken. Ada is the
>> only language I know which implements OO consistently in a properly typed
>> way.
> 
> No way. :-D With type/interface schizophrenia, lack of MI, controlled as a
> base class,

I didn't say "completely", I said "consistently". True, lack of MI and
having first- and second-class types is a serious incompleteness. You can
add lack of full MD to the list, missing delegation support, lack of
abstract interfaces for record, array, access, task, protected types.

> unsafe (!!!) handling of dispatch during
> initialization/finalization

Well, I don't consider Initialize/Finalize stuff as
initialization/finalization. To me it is hack made to avoid serious dealing
with the issue. Thus it is not an inconsistency but an incompleteness of
the Ada initialization/finalization model. It would be possible to add
necessary hooks and leave Initialize/Finalize as is.

More serious is the garbage limited return stuff. That borders
inconsistency and likely crosses the border. A lighter issue is the return
statement which allows multiple initialization-finalization rounds on the
"same" object. Yet another serious issue is renaming to a differently
constrained subtype. That is plain inconsistent.

> and no support for type covariance on return
> type Ada is way more broken than other languages I am aware of.

I don't understand this. The return type is covariant in Ada.

> No trolling here - I really consider the above issues to be problems. OO
> in Ada definitely looks like a patchwork, not a consistent language
> feature.

Yes, but again a patchwork may mean incompleteness or inconsistency (or
both (:-))

To me the most important thing is making classes of types typed. T /=
T'Class. Ada did it. The rest could be fixed, if there were a desire.
Unfortunately, there is none.

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