Re: domains aren't subtypes, right?

"Jonathan Leffler" <jleffler_at_earthlink.net> wrote in message news:3EDEC78B.7070806_at_earthlink.net...
> I disagree. You need to be able to store intervals (or durations),
> and those are distinctly different from points on the timeline (which
> is what a timestamp represents). Now, if you said the only type to be
> used was an interval, with timestamps simply being an interval from a
> fixed point on the timeline, then you might be in with a chance - but
> not a very good one - of justifying your proposition.

In Ariphmetics do we really use 2 sorts of numbers: one for identification and the other one for subtraction? If we want full analogy with ariphmetics, then both timestamp and time interval would better be interpreted as a real number in some units. For timestamp we just also have to agree about the reference point where time = 0. I guess "Time" would be much better name for the proposed domain -- it certainly sounds more physics-based than say "Timestamp" or "Date".

I find this whole domain idea being anti-abstraction. Timestamp with time zone. As if given the absolute time and location one cannot figure how to print a time that would be appropriate for the users at this location to understand. A separate domain for character strings less than 20 bytes! Received on Thu Jun 05 2003 - 18:09:19 CEST