types_directive

d1 = Time1(2001, 2, 3, 60);
newDate = add(d1, 7); # check that a Time1 instance is accepted where Date is expected
if (newDate.day != 10)
  error
endif

d2 = Time2(1999, 8, 7, 60);
newDate = add(d2, 7); # check that a Time2 instance is accepted where Date is expected
if (newDate.day != 14)
  error
endif