Re: Clean Object Class Design -- Circle/Ellipse
Date: Tue, 21 Aug 2001 04:34:13 GMT
Message-ID: <9xlg7.27549$1p1.1978478_at_bgtnsc04-news.ops.worldnet.att.net>
"Marc Gluch" <marc.gluch_at_mindtap.com> wrote in message
news:3b81d266.3858753634_at_news.grpvine1.tx.home.com...
> On Mon, 20 Aug 2001 03:19:30 GMT, "Richard MacDonald"
> <macdonaldrj_at_att.net> wrote:
>
>
> >> I think I mentioned it in some earlier post.
> >> Magnitude provides axiomatization of the ordering relationship ("<").
> >> Number (derived from Magnitude) overrides "< " appropriately for its
> >> domain.
> >>
> >Got it. You moved that up a little higher again. (I am a Smalltalker.)
> >I'm still lost on the issue of the operations that "jump outside" the
> >argument's domain. Are you saying that any operation that does so
> >must move up the hierarchy until it encompasses both the argument
> >and the result? So you disallow the "jump"?
>
> I'm not sure about the meaning you assign to "jump".
> The way I prefer to put it is to say that
> one specialization/implementation should not redefine another.
> They all should be (parallel) implementations of a generic
> (ala CLOS) function.
>
Ok, but this confuses me. You seemed to be trying to
build up the type theory strictly from axioms that were limited
to staying "within" a type hierarchy. The above statement does
not have this limitation.
P.S. If I'm confused, I bet I'm not the only one. I am stealing Bob's example, after all :-) Received on Tue Aug 21 2001 - 06:34:13 CEST