func (a Position) Less(b Position) bool {
return rational.Less(rational.Rational(a), rational.Rational(b))
}
func (a Duration) Greater(b Duration) bool {
return rational.Greater(rational.Rational(a), rational.Rational(b))
}
func (p Position) Add(d Duration) Position {
return Position(rational.Add(rational.Rational(p), rational.Rational(d)))
}
func (d Duration) Add(other Duration) Duration {
return Duration(rational.Add(rational.Rational(d), rational.Rational(other)))
}