Re: Enforcing initialization protocol for protected type

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

On Fri, 11 Sep 2009 17:24:57 -0500, Randy Brukardt wrote:

> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> wrote in message 
> news:1rusjydws2ko.rpfwzoyv4bzj$.dlg@40tude.net...
> ...
>> P.S. It looks like a language design bug. If allowed then at least it
>> should have been like:
>>
>>   Obj: subtype Rec (new Disc);
>>      -- An anonymous subtype is declared for Obj
> 
> I think most of us consider "coextensions" a language design bug. Indeed, 
> that is about the nicest thing I can say about them. There are many of us 
> who think that allocators of anonymous access types should simply be illegal 
> (in all contexts), because what they mean currently depends so heavily on 
> context and that makes them a maintenance nightmare (at best).

Yet strange semantic constructs keep on appearing in Ada. That is IMO
because people fail to face the "tragic" reality, that MI must be there,
that initialization must be handled properly, that discriminant is a
constraint and not a pointer, that protected type must be tagged and so on.

Look how an Ada programmers must twist his design just because protected
type cannot be derived from, or that no class-wide component can be put
into it.

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