Re: Nested Relations / RVAs / NFNF

"Marshall Spight" <mspight_at_dnai.com> wrote in message news:17Rfd.316248$MQ5.24677_at_attbi_s52...

> I note that in the type theory world, attention is paid to the
appropriateness
> of associated operations. For example, one might choose to have separate
> *types* for metric units and for English units, and allow the type system
> to either prevent invalid crossovers or convert for you. Also, you can do
> things like have a separate numeric type for speed, distance, and time,
> or even things like length, area, and volume. The type of the multipy
> operation for (length, length) is area; for (length, area) is volume, etc.

I'm following this with interest, although it's kinda unfamiliar ground to me.

So, could you have two distinct types that share a common domain? That is, they both have exactly the same
possible values, with the same semantics, but they don't allow the same operations on them? Received on Wed Oct 27 2004 - 21:04:37 CEST