partialfunctionsorelse

pforelse.scala

val positivePF: PartialFunction[Int, String] = { case i if i > 0 => "Positive"}
                                                  //> positivePF  : PartialFunction[Int,String] = <function1>
	
val negativePF: PartialFunction[Int, String] = { case i if i < 0 => "Negative"}
                                                  //> negativePF  : PartialFunction[Int,String] = <function1>
	
val zeroPF: PartialFunction[Int, String] = { case 0 => "Zero"}
                                                  //> zeroPF  : PartialFunction[Int,String] = <function1>
	
// combine the indivitual partial functions to form one that covers all of them
val number = positivePF orElse negativePF orElse zeroPF
                                                  //> number  : PartialFunction[Int,String] = <function1>
number(0)                                 //> res10: String = Zero
number(1)                                 //> res11: String = Positive
number(-1)                                //> res12: String = Negative
	
// which is equivalent to a case statement that is composed out of
// the case statements that created the individual partial functions
val numberPF: PartialFunction[Int, String] = {
  case i if i > 0 => "Positive"
  case i if i < 0 => "Negative"
  case 0 => "Zero"
}                                         //> numberPF  : PartialFunction[Int,String] = <function1>

numberPF(0)                               //> res13: String = Zero
numberPF(1)                               //> res14: String = Positive
numberPF(-1)                              //> res15: String = Negative
		
	
// and here with full match statement, the only difference is that this one is a regular function
def numberF(x: Int): String = x match {
  case i if i > 0 => "Positive"
  case i if i < 0 => "Negative"
  case 0 => "Zero"
}                                         //> numberF: (x: Int)String