Re: Possible Ada deficiency?

[Martin Krischik <martin@krischik.com>]

danmcleran@hotmail.com wrote:

> 
>> just as anybody can type
>>
>> #define private public
>>
>> in C++.
>>
>> With Regards
>>
>> Martin
> 
> Yes. This kind of thing is evil.

Of course you can do the same in Ada using the "Cut/Copy/Paste" feature of
you favourite Editor and Unchecked_Conversion. For the determined you can
make it only more difficult. 

You know, after using C++ for a few years I started to create only classes
like this:

class X_self;

class X
   {
   public:

   ..........

   private:

      X_self& X;

   };

Reason: The main incompatiblily problem is the result of the sizeof
operator. And only opaque types can solve that.

But then I have to agree that the C++ "private" has enormous marketing
value.

> One of the main reasons I find Ada so 
> appealing is that it has fewer loopholes for this kind of stuff to get
> through. I am surprised that child packages have as much visibility as
> they do, and that there is no way to prevent it, though.

If you write a child package you should know what you are doing. Mind you,
child packages where new for Ada 95. In Ada 83 there was only:

package Parent

  package Child

  private

  end Child;

private

end Parent;

package body Parent

  package body Child is seperate;

end Parent;

With this contruct you actualy know all possible child packages. There must
have been a good reason why the new Child packages got access the private
data as well. But then the old child packages even have access to the body
informations.

Martin
-- 
mailto://krischik@users.sourceforge.net
http://www.ada.krischik.com