Calendar package is copyright 2004 by Alfonso Ranieri.
    All Rights Are Reserved.

    These classes are free for users: they don't have to pay
    anything; they are not free for developers: I want to receive
    a registered copy of your program if it uses them.

    Calendar.mcc is a MUIC_Group subclass.

    Calenda.mcc allows to easily define a date in the range 
    1-gen-1752, 31-dic-2400.

    A Calendar object always contains a valid date as a Gregorian
    number.
    
    You may specify a date at any time via 
        MUIA_Calendar_Greg
        MUIA_Calendar_Day
        MUIA_Calendar_Month
        MUIA_Calendar_Year
    
    The default date is the current system date (today).

    If you specify MUIA_Calendar_Greg, that is rounded and used
    as the current date.

    If you specify any of MUIA_Calendar_Day, MUIA_Calendar_Month
    and MUIA_Calendar_Year, their value are rounded and used as
    the current date.
    
    So, if today is 2-feb-2004, after
    
    cal = CalendarObject,
        MUIA_CAlendar_Day, 20,
    End;
    
    the date of "cal" is 20-feb-2004.

    You may set the date to today at any time using
    MUIM_Calendar_Today.

    You may add days, monthes and year at the current date at any
    time via MUIM_Calendar_AddDay, MUIM_Calendar_AddMonth and
    MUIM_Calendar_AddYear.

    The resultant dates are rounded to the most reasonable
    result, so if the current date is 30-apr-2004, after a
    DoMethod(obj,MUIM_Calendar_AddMonth,-2), the resultant date
    is 29-apr-2004.

    Note that you should always store your your dates as ULONG
    Gregorian numbers: no method to parse a date and to produce a
    Gregorian number is actually implemented.

    Because of in your program you would like to handle with
    Gregorian dates outside Calendar.mcc, a small linker library,
    the same used in Calendar.mcc, is included in Calendar.mcc
    archive, so that you may reuse its functions.

    Calendar.mcc reads at startup the file ENVARC:CALMCCHOLYDAYS.
    The lines of the file are parsed with the template
    DAY/A/N,MONTH/A/N,A=ANNIVERSARY/S so that you you may specify
    your holidays and anniversaries.
    
    In the following the attribute scheme is ISGN
    

    To convert a date to a valid format us CALValidateDate().

    To use a Calendar.mcc funtion, you must can:

    - open Calendar.mmc version 18 or higher !!!
      struct Library *CalendarBase;
      CalendarBase = OpenLibrary("MUI/Calendar.mcc",18);

    - if you created a Calendar.mcc object with MUIA_Calendar_MinVer 18 !!!
      struct Library *CalendarBase;
      get(calObj,MUIA_Calendar_Base,&CalendarBase);

    - if you subclassed Calendar.mcc:
      struct Library *CalendarBase;
      CalendarBase = calendarSubclass->mcc_UserData;