Below are the two partial function that are expected to perform sme tasks but defined in diffrent ways.
val pf1 : PartialFunction[String, String] = {
case s : String if (s != null) => s.toUpperCase()
}
//> pf1 : PartialFunction[String,String] = <function1>
val lift1 = pf1.lift
//> lift1 : String => Option[String] = <function1>
val d1 = lift1(null)
//> d1 : Option[String] = None
val d2 = lift1("hello world")
//> d2 : Option[String] = Some(hello world)
val pf2 = PartialFunction[String, String] {
case s : String if(s != null) => s.toUpperCase()
}
//> pf2 : PartialFunction[String,String] = <function1>
val lift2 = pf2.lift
//> lift2 : String => Option[String] = <function1>
val d3 = lift2(null)
//> scala.MatchError: null
val d4 = lift2("hii")
//> d4 : Option[String] = Some(hii)
Why passing null to lift2 gives MatchError, when the definition of both lift1 and lift2 is same?