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Subject: Re: Imitation is the sincerest form of flattery
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Date: 2003-03-23T11:12:07+12:00
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"Pascal Obry" <p.obry@wanadoo.fr> wrote in message
news:ubs03lcdz.fsf@wanadoo.fr...
>
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
>
> > > But how do you access element into this array, what would be done
> > > for:
> > >
> > >    M : Sparse_Matix (1 .. 7, 1 .. 90);
> > >
> > >    M (2, 6) := ...;
> >
> > I have to prove an implementation for Set_Element, I suppose. When I
declare
> > that Sparse_Matrix an array, I have to override all the abstract methods
of
> > the universal array type might have. Set_Element is one of them.
>
> You mean that the compiler must generate a call to Set_Element/Get_Element
for
> every reference to an array item, right ?

Well, I don't know what Dmitry meant of course :)

But my case would be that of the compiler knowing
pretty darn well what the index is - it could be just
a simple integer or so. The whole point is not about
hiding the info from the compiler (how could you?)
but about hiding/decoupling it from the clients of
the package. And keeping control of it. And being
able to change it without breaking all the clients ...