Re: Stupid question

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

On 12 Apr 2007 15:02:18 -0700, Adam Beneschan wrote:

> I wrote:
> 
>> On Apr 12, 1:05 pm, "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de>
>> wrote:
>>
>>> generic
>>> package A is
>>>    A1 : Integer;
>>> end A;
>>
>>> generic
>>> package A.B is
>>> end A.B;
>>
>>> with A.B;
>>> generic
>>>    with package A_B is new A.B (<>);
>>> package C is
>>>    -- What is the name of A1 from A of A_B?
>>> end C;
>>
>> I am betting that if you try to compile just the code snippet you've
>> got, you will figure out your answer.
> 
> Sorry about that answer.  I made the rash assumption that you would be
> using a compiler that works.  But apparently that's not necessarily
> the case.
> 
> The version of GNAT I've got installed compiles the above code with no
> errors, despite the fact that it's illegal.  I was assuming that you'd
> get an error and the error would help you figure out what was wrong;
> but I didn't figure on this happening.

[OK, GNAT has *lots* of problems with generics, it always had. I wonder
when AdaCore would finally decide to rewrite generics from scrap. But
that's aside.]

Are you saying that it is illegal to refer to generic children of generic
packages as generic packages? I don't see where 12.7 states it. 12.7(4):

"The generic_package_name shall denote a generic package (the template for
the formal package); the formal package is an instance of the template."

A.B is definitely a generic package to me.

> The problem is that you cannot refer to A.B the way you did in your
> "with package" declaration; you can only refer to A_Inst.B where
> A_Inst is an instance of A (A_Inst could be another generic formal
> package).

Well, you mean that dreadful:

with A.B;
generic
    with package A_Inst is new A (<>);
    with package A_B_Inst is new A_Inst.B (<>);
package C is
end C;

This what I am trying to avoid. It is awful (and GNAT has problems with the
constructs like that). 

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