On Mon, May 15, 2006 at 06:02:34PM +0200, Gerhard Wesp wrote:
Having implemented several major frameworks in C++ in which time played a crucial rule, I have a pretty firm view on the subject: No time type should include information about relative to which point it is measured.
This doesn't give arguments.
that the two are the same thing, but I'd argue that it would be better to make TWO types.
I strongly disagree, for the above reasoning.
Though you are theoretically correct to say that also the time as returned by -whatever- (ie, gettimeofday) is relative to some point, it isn't very practical to consider it's value relative. The concept of "NOW" seems clear to me. And "NOW" is an absolute time, not a relative one. The fact that one HAS to store/represent it as a relative time is exactly what is so confusing, and THEREFORE calls for a separate type. It makes no sense to code, Time t1 = now(); Time t2 = now(); Time t3 = t1 + t2; as the result of the addition would be dependent on the time that the *implementation* of Time is relative to (ie, 1970). But the coder in general will not care if 'now' is relative stored relative to 1970 or to 2005: he should be shielded from that. Therefore, adding Time + Time should not compile. I think these are sound argument FOR two types, and AGAINST just a single type for relative time. -- Carlo Wood <carlo@alinoe.com>