Re: High-Integrity OO and controlled types

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

On Tue, 03 May 2011 12:53:13 -0400, Robert A Duff wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
> 
>> There are three meaning of being controlled:
>>
>> 1. Ada 83 used it to refer memory allocation (pragma Controlled)
>> 2. Since Ada 95 it is both
>> 2.a. An ability to influence initialization and finalization
>> 2.b. An ability to have a [non-generic] class
> 
> I am unaware of 2.b.  I know there are two meanings: 1 and 2.a.

OK, 2.b (T'Class) is actually allowed for any tagged type.

>> Yes, things need to be sorted out.
> 
> Shrug.  Nobody uses pragma Controlled, so I don't see a huge problem
> with the terminology.

I think that Maciej meant that initialization and finalization is
orthogonal to an ability to form a class (or being tagged as one possible
implementation of this). I agree with that, but in my view both should be
allowed to all types anyway. If Ada reached that level of regularity I
would like you not care about separation, but unfortunately it has not.
Moreover many (not me) think that taggedness should be kept isolated, so
the restriction goes. If this separation is to be maintained, one should
make initialization and finalization independent on that.

So, my opinion depends on path the language roadmap.

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