Re: Protected types and visibility of their internals

[Georg Bauhaus <rm.dash-bauhaus@futureapps.de>]

Maciej Sobczak schrieb:
> Consider a protected type in some package:
> 
> package P is
>    protected type PT is
>       procedure Foo;
>    private
>       X : Some_Type;
>    end PT;
> end P;
> ...
> Can you recommend some other solution that enforces strict coding
> practice?

I'm assuming you want clients to consider PT  some synchronized
abstract data type? Using Ada 83, a passive task might have
worked :-) Using Ada 95, I'd consider moving the protected
type to the body, and provide procedural wrappers.
Using current Ada, the following might work, though
I have probably made a few grammatical mistakes in a rush;
all GNATs crash on this is some way or other:

package News21 is

    type Only_Ops is synchronized interface;
    procedure Foo(It: in out Only_Ops) is abstract;

    type PT is limited new Only_Ops with private;

private

    type Some_Type is null record;

    protected type PT is  new Only_Ops with
       overriding
       procedure Foo;
    private
       X : Some_Type;
    end PT;

end News21;


--
Georg Bauhaus
Y A Time Drain  http://www.9toX.de