Re: Signature Package With Generic Proceedure

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

On Sat, 21 Jul 2012 15:22:36 -0700 (PDT), Adam Beneschan wrote:

> On Saturday, July 21, 2012 10:22:25 AM UTC-7, Keean Schupke wrote:
>> If I have a package which defines a procedure like:
>> 
>> generic
>>     with procedure Process(Set : in out Set_Type);
>> procedure Update(Set : in out Set_Type);
>> 
>> How do a declare a Signature package that includes this?
>> 
>> generic
>>     with generic
>>         with procedure Process(Set : in out Set_Type);
>>     procedure Update(Set : in out Set_Type);
>> package Set_Signature is end;
>> 
>> Is not allowed. Is there some way to do this with nested packages?
> 
> There's no such thing as "with generic" in Ada. That is, there is no way
> to set things up so that you can instantiate a generic like this:
> 
>    package An_Instantiation is new A_Generic (G1);
> 
> where G1 is the name of a *generic* subprogram or package. Nor can I
> think of a reason why you'd want to.  Perhaps if you gave us an example of
> what you're trying to accomplish?

Probably it is passing an instance of a specific generic procedure to a
generic package?

Note, rather than passing any procedure with matching signature, e.g.

generic
   with procedure Foo (...);
package Boo ...

, only such Foo, which is an instance of a generic procedure Baz. Imaginary
syntax borrowed from packages:

generic
   with procedure Foo is new Baz (<>); -- This is not Ada!
package Boo ...

This is impossible. An obvious solution is to place Baz into a generic
package and pass an instance of that package instead.

(Ada's generics lack many formal types, e.g. this one)

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