Interval.empty
bool empty() @property const pure nothrowWhether the interval's length is 0, that is, whether begin == end.
Example: -------------------- assert(Interval!Date(Date(1996, 1, 2), Date(1996, 1, 2)).empty); assert(!Interval!Date(Date(1996, 1, 2), Date(2012, 3, 1)).empty); --------------------