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Re: Tim Sweeney on Programming Languages
At 12:15 Uhr +0100 07.02.2000, Maarten Hazewinkel wrote:
> In article <1e5j7vy.1wbl2xsdh8on8N%schuerig@acm.org>,
> schuerig@acm.org (Michael Schuerig) wrote:
> >So, he wants to express abstractly the relationship among a bunch of
> >classes. This is exactly what he can get with interfaces and factories.
>
> Yes, you can fabricate this kind of thing with interfaces and factories.
> BUT, that requires that the original author of the library/framework
>built
> in those interfaces and factories so that others can use that to
>extend the
> framework.
>
> It comes down to something that's repeatedly mentioned in the
>article: It's
> possible to build higher level constructs without language support, but
> it's a lot of work and generally not really compatible with other
>libraries
> at those higher level constructs.
I agree in principle, but not in practice. The mechanism that Sweeney
proposes is not much better than interfaces and factories. The point is
that both require forethought. You have to explicitly use his "virtual
classes" to reap their benefits. If you didn't think of this, you're as
much out of luck as with any other approach.
Michael
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