internal Date(int year, int month, int day)
{
if (month < 0 || month > 11)
{
throw ArgErr.make("month " + month).val;
}
if (day < 1 || day > DateTime.numDaysInMonth(year, month))
{
throw ArgErr.make("day " + day).val;
}
this.m_year = (short)year;
this.m_month = (byte)month;
this.m_day = (byte)day;
}