// requires scalaz for Option to have map and flatmap

def safeDivide(a: Double, b: Double): Option[Double] = b match {
  case 0 => None
  case _ => Some(a / b)
}

def example1 = safeDivide(5, 9).flatMap(a => safeDivide(3, a))

def example2 = for {
  a <- safeDivide(5, 9)
  b <- safeDivide(3, a)
} yield b