Number of months in a year.
Current year.
Test if a value corresponds to a leap year in the Gregorian calendar.
Determine the day of the year.
Determine the number of ISO weeks in a year according to the Gregorian calendar.
Determine the quarter of the year.
Determine the number of days in a year according to the Gregorian calendar.
Determine the number of hours in a year according to the Gregorian calendar.
Determine the number of seconds in a year according to the Gregorian calendar.
Test if a value is the current year.
Determine the number of minutes in a year according to the Gregorian calendar.
