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Newsgroups: comp.lang.ada
Subject: Re: Dynamich Dispatching...
References: <cjmi3n$iat$03$1@news.t-online.com> <87zn33r5pq.fsf@insalien.org>
 <Lz48d.2246$M05.992@newsread3.news.pas.earthlink.net>
From: Ludovic Brenta <ludovic.brenta@insalien.org>
Date: Mon, 04 Oct 2004 23:01:55 +0200
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Date: 2004-10-04T23:05:25+02:00
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Jeffrey Carter writes:
> Ludovic Brenta wrote:
>
>> package Objects is
>>    type Object is tagged private;
>>    procedure Draw (O : in Object); -- a primitive suprogram
>>    procedure Draw_Any (O : in Object'Class); -- not a primitive
>
> Draw_Any is unnecessary. Draw may be called with any type in
> Object'Class.

Yes, I know, but this thread is about dynamic dispatching.  If I
write:

with Circles;
procedure Main
   C : Circles.Circle;
begin
   Draw (C);
end Main;

this is static dispatching since the type of C is known at compile
time, and no 'Class was ever used.  Incidentally, for those not aware
of it, Ada has a pragma Restriction (No_Dispatch) which makes 'Class
illegal or just this reason (RM H.4(19)).

-- 
Ludovic Brenta.