Re: default formal parameters in generic declarations

["Dr. Adrian Wrigley" <amtw@linuxchip.demon.co.uk.uk.uk>]

On Mon, 03 Mar 2008 07:42:40 -0500, Stephen Leake wrote:

> Eric Hughes <eric.eh9@gmail.com> writes:
> 
>> I would like to implement this in Ada, but the absence of a default
>> package parameter means that instantiation is horribly clunky and that
>> only the most dedicated would use it.
> 
> I don't see why this would be "horribly klunky"; they typical user
> will do:
> 
> package My_Instance is new Generic_Package 
>     (Aspect_Package => Null_Aspect_Package,
>      foo => Bar,
>      ...);

Perhaps I am being a little stupid, but how does this work?
Could you flesh out the detail a little more?

What kind of parameter is Aspect_Package? and where does
the Null_Aspect_Package come from?
--
Adrian