Упс... наверное, так правильнее...

dev 18.11.2005 20:03

# Parameters: year is natural number, month is int 1..12.
# Result is number of days at a month (int).
@days_per_month[month;year]
^if($month == 2 && ^is_leap_year[$year]){
	$result(29)
}{
	^switch($month){
		^case(1;3;5;7;10;12){$result(31)}
		^case(2){$result(28)}
		^case(4;6;9;11){$result(30)}
	}
}

# Parameter (year) is natural number, result is bool.
# Returns true if year is leap, else false.
@is_leap_year[year]
$result(($year&3) == 0 && $year%100 != 0 || $year%400 == 0)