:- module calendar.
:- interface.
:- type date.
:- type day_of_month.
:- type day_of_week
	where	type_is_abstract_enum(3).
:- type days.
:- type duration.
:- type hour.
:- type hours.
:- type microsecond.
:- type microseconds.
:- type minute.
:- type minutes.
:- type month
	where	type_is_abstract_enum(4).
:- type months.
:- type second.
:- type seconds.
:- type year.
:- type years.
