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From: matthias_k <nospam@digitalraid.com>
Newsgroups: comp.lang.ada
Subject: Re: Classwide Parameter?
Date: Tue, 12 Oct 2004 10:01:34 +0200
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Date: 2004-10-12T10:01:34+02:00
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Matthew Heaney wrote:
> matthias_k <nospam@digitalraid.com> writes:
> 
> 
>>Thanks for that answer. However, I'm still having problems (I have
>>rewritten the code to be in one single package now):
>>
>><snip>
>>package Graphics is
>>
>>    type Shape is abstract tagged null record;
>>    procedure Draw (Obj: Shape'Class);
> 
> 
> Get rid of this operation.  It's a "class-wide" operation (like a static
> method in C++), and hence the operation isn't primitive for the type
> (and therefore doesn't dispatch).
> 
> 

Oha? I thought it would be analogous to 'virtual' in C++, not static.
If I leave out the method completely, then this is not what I know as 
'Inheritance' anymore.
Shape is supposed to be an abstract base class, which -declares- (not 
necessarily -defines-) a common interface for its subtypes. The code I 
posted may not reflect this too well, it's just samplecode.
I doubt -any- dynamic binding will happen when completely leaving out 
Shape's Draw method.

And btw.: What does dispatch mean? :) Is that the Ada term for dynamic 
binding?

- Matthias