Re: Recursive parameters in generics

[Adam Beneschan <adam@irvine.com>]

On Jul 23, 11:20 am, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
wrote:
> Hi there,
>
> out of curiosity, recently experimenting with workarounds for generics, I
> invented a construct, which puzzles me. Is the following legal:
>
> generic
>    S : String;
> package A is
>    S_Of : String renames S;
> end A;
> -----------------------------------
> with A;
> generic
>    S : String;
>    with package This_A is new A (S => S);
> package B is
> end B;
> -----------------------------------
> with A;
> package My_A is new A (S => "whatever");
> -----------------------------------
> with My_A;
> with B;
> package My_B is
>    new B (This_A => My_A, S => My_A.S_Of);
> -----------------------------------
> One could think that My_B would take S_Of from an instance of A and then
> pass it back to A.

I don't see why this would be any different from

package My_B is new B (S => "whatever", This_A => My_A);

If you're thinking about My_B passing something back to A, you're
probably thinking about the whole problem sideways.  My_B doesn't
instantiate A at all, it uses an already-existing instance of A.

                 -- Adam