lifted options

liftedOptions.scala

// A lift function that takes a regular function that cannot handle options
// and uses for to call it only with Some(...) cases
def lift1[A, B](f: Function1[A, B]): Function1[Option[A], Option[B]] = {
  (oa: Option[A]) =>
    for (a <- oa) yield f(a)
}                                               //> lift1: [A, B](f: A => B)Option[A] => Option[B]

// Same for a 2 argument function, if any of the arguments is None, the function simply returns None
def lift2[A, B, C, D](f: Function2[A, B, C]): Function2[Option[A], Option[B], Option[C]] = {
  (oa: Option[A], ob: Option[B]) =>
    for (a <- oa; b <- ob) yield f(a, b)
}                                               //> lift2: [A, B, C, D](f: (A, B) => C)(Option[A], Option[B]) => Option[C]
  
  
def strCountChars(value: String) = value.length //> strCountChars: (value: String)Int
  
def strCountChars2(value1: String, value2: String) = value1.length + value2.length
                                                //> strCountChars2: (value1: String, value2: String)Int
	
//strCountChars(null) // this will give a null pointer error

// Lift the 1 argument function into its optionable version
val liftedCountChars = lift1(strCountChars)     //> liftedCountChars  : Option[String] => Option[Int] = <function1>

// Lift the 2 argument function into its optionable version
val liftedCountChars2 = lift2(strCountChars2)   //> liftedCountChars2  : (Option[String], Option[String]) => Option[Int] = <function2>

liftedCountChars(Option(null))                         //> res0: Option[Int] = None

liftedCountChars(Option("Something"))                  //> res1: Option[Int] = Some(9)

liftedCountChars2(Option(null), Option("Something"))   //> res1: Option[Int] = None 

liftedCountChars2(Option("Something"), Option(null))   //> res2: Option[Int] = None

liftedCountChars2(Option("Something"), Option("Good")) //> res3: Option[Int] = Some(13)