This class holds calendar date information: the day, month and year, used in the PtCalendar widget. The values for day and month start with 0, so they are always 1 less than the actual date or month number. For example, April 21, 2000 is expressed as:
{PtCalendarDate (day . 20) (month . 3) (year . 2000)}
An integer ranging from 0 - 30 specifying the day of the month.
An integer ranging from 0 - 11 specifying the month of year.
An integer ranging from -32767 - +32767 specifying the year.