Re: Polymorphism

[slos <new.stephane.los@gmail.com>]

Le jeudi 7 mai 2015 09:41:55 UTC+2, Dmitry A. Kazakov a écrit :
> On Wed, 6 May 2015 16:05:28 -0700 (PDT), slos wrote:
> 
> > Please consider the following simple case :
> > 
> > package Object is
> [...]    
> > end Circle;
> > 
> > I'd like function Object.Area to stay private but the compiler doesn't see
> > it like that and complains if I try to move it in the private part.
> > 
> > In other words, I'd like to not expose internals to clients of the package.
> > 
> > Any hint to achieve that ?
> 
> If you privately override anything for something that is publicly
> dynamically polymorphic [~tagged], then that is not any private because you
> can [and must] be able to call the overriding body.
> 
> The Ada's types model is that Circle.Instance has the function Area anyway.
> It is either implemented per inheritance of the parent's type
> implementation (if exists) or by providing a new body per overriding. Thus
> moving overriding into private changes nothing.
> 
> I don't know why it is not allowed. Moreover, it probably would make sense
> to move all declarations of overriding into private or even further into
> the package body because the fact of overriding is mere an implementation
> detail, since the primitive subroutine is there anyway no matter what.
> 
> -- 
> Regards,
> Dmitry A. Kazakov
> http://www.dmitry-kazakov.de

Thank you Dmitry for your answer.

BR,
Stéphane