Option vs null

gistfile1.txt

def fun(k:Int)={ 
  val x = f(k)
  val y = g(x)
  val z = h(y)
  x+y+z
}

// If f,g,h return Option
def fun1(k:Int)=for { 
  x <- f(k)
  y <- g(x)
  z <- h(y)
} yield {x+y+z}

// If f,g,h return null
def fun2(k:Int)=for { 
  x <- Option(f(k)))
  y <- Option(g(x))
  z <- Option(h(y))
} yield {x+y+z}

// With Option you can keep the program structure, with null you can't :
def fun4(k:Int)= {
  val x=f(k)
  if (x != null) {
    val y= g(x)
    if (y != null) {
      val z=h(z)
      if (z != null) x+y+z else null 
    } else null 
  } else null 
}

//Also, Option is a different type than the normal value, and the compiler will signal if you mix both, unlike null