:- protocol(datep). :- info([ version is 1.0, authors is 'Paulo Moura', date is 2000/7/24, comment is 'Date protocol.']). :- public(today/3). :- mode(today(-integer, -integer, -integer), one). :- info(now/3, [ comment is 'Returns current date.', argnames is ['Year', 'Month', 'Day']]). :- public(leap_year/1). :- mode(leap_year(+integer), zero_or_one). :- info(empty/1, [comment is 'True if the argument is a leap year.', argnames is ['Year']]). :- public(name_of_day/3). :- mode(name_of_day(?integer, ?atom, ?atom), zero_or_more). :- info(valid/3, [ comment is 'Name and short name of day.', argnames is ['Index', 'Name', 'Short']]). :- public(name_of_month/3). :- mode(name_of_month(?integer, ?atom, ?atom), zero_or_more). :- info(valid/3, [ comment is 'Name and short name of month.', argnames is ['Index', 'Name', 'Short']]). :- public(days_in_month/3). :- mode(days_in_month(?integer, +integer, ?integer), zero_or_more). :- info(valid/3, [ comment is 'Number of days in a month.', argnames is ['Month', 'Year', 'Days']]). :- public(valid/3). :- mode(valid(@integer, @integer, @integer), zero_or_one). :- info(valid/3, [ comment is 'True if the arguments represent a valid date.', argnames is ['Year', 'Month', 'Day']]). :- end_protocol.