Re: Ada 2005?

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

On 17 Dec 2004 20:27:44 -0800, conradwt@runbox.com wrote:

> It seems that I'm trying to mimic the behavior of a OO language in a
> procedural language when converting C++ to Ada.  Is this correct?  If
> so, why doesn't Ada have OO contructs similar to C++,
> Java, Eiffel, and Smalltalk to name a few where one passes a message to
> an instance of a class?

Because it is inconsistent. Method is not a property of a class (=type),
the relation is not 1-1. So the idea of a message sent to invoke a member
of an object is plainly wrong. Consider nasty consequences in C++:

class Device
{
public :
   void Copy (From : Device);
};

The above is infeasible, it will not dispatch in From for:

Printer.Copy (Display);

what is the recipient here? Printer or Display? The only correct answer is
both. So Copy should be defined not on Device, but on Device x Device
(tuple).

The word class as it is used in C++ is just a type. There is no need to
call types classes. BTW, it has nothing to do with OO. Ada uses the word
"class" for types of polymorphic objects. It is specified as T'Class. Using
the same word for something else would be misleading.

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