Jeff Garland wrote:
Wow, that's amazing. Replace quantity_vector with time_duration and quantity_point with time_point and you have the core concepts behind date-time. And the 32 versus zero -- seems an awful lot like an epoch_time adjustment. So I suppose I'm saying I believe there is something fundamental here :-)
Yes, there is. If you dig back in the archives, I tried to explain it all before, but obviously not very well. Suffice to say that a "time point" and a "point quantity" are the same type of thing and that the difference between any two such things is a "vector quantity" or equivalently a "time_duration". Mathematicians have identified the common abstract concepts underlying these things, and I went on and on about this earlier. But I think I'm going to resist reviving all that, because I don't think it's particularly helpful. I like Matt's terminology, because it seems to be more meaningful for everyone.