Re: Can you help with an Ada 95 OO Problem

[jsa@alexandria (Jon S Anthony)]

In article <mheaney-ya023280001801972026220001@news.ni.net> mheaney@ni.net (Matthew Heaney) writes:

> Try a view conversion of the designated object, to get at its primitive
> operation:
> 
>    Http.Headers.Init (Obj => Http.Headers.Header (Header_Ref.all));
> 
> I'm not sure that will work, but try it and let me know (so I can learn, too!).

He doesn't have a "non-access" parameter version of the operation, so
you need to add a 'Access to the converted object.  That should work,
but you can make it simpler.  Just,

   Http.Headers.Init (Obj => Http.Headers.Header(Obj.all)'Access);

The new access object is irrelevant.


> There was some debate a while back about how to invoke the parent's
> implementation of the operation.  There was one case (cited by Mitch) that
> required a very un-obvious technique.  Perhaps your difficulties mean

I think that had to do with "smoothly" changing the parent (by adding
in an intermediate).  This is fixed by using a subtype.  Works just
fine.  I suppose the 'Parent thing would look a little nicer...

/Jon

-- 
Jon Anthony
Organon Motives, Inc.
Belmont, MA 02178
617.484.3383
jsa@organon.com