std.datetime.date.DateTimeException if isAD is true.
assert(DateTime(Date(0, 1, 1), TimeOfDay(12, 30, 33)).yearBC == 1); assert(DateTime(Date(-1, 1, 1), TimeOfDay(10, 7, 2)).yearBC == 2); assert(DateTime(Date(-100, 1, 1), TimeOfDay(4, 59, 0)).yearBC == 101);
Year B.C. of the Gregorian Calendar counting year 0 as 1 B.C.