From: Guillaume Melquiond (guillaume.melquiond_at_[hidden])
Date: 2006-05-16 01:54:12
Le lundi 15 mai 2006 à 22:21 -0700, Jeff Garland a écrit :
> In date_time there's -inf, +inf, and not_a_date_time. There's
> no union internally used to represent them. These values are extremely
> useful for writing real programs and have obvious mappings into the real
> world -- trust me, I've used them in a real world scheduling system. In
> fact, since date_time uses integers internally the special values are
> simply implemented as a reserved number value. nadt is essentially
> max_int, +inf == max_int - 1 and -inf == min_int.
For symmetry purpose, I would have chosen nadt == min_int, +inf =
max_int, -inf = min_int + 1. That way, in usual two-complement
representations, there is as much positive than negative finite values
and infinities have the same absolute representation. Just pointing it
out in case nobody did before.
Best regards,
Guillaume