Question

In scala I can write:

val pf: PartialFunction[String, Unit] = {case s => println(s)}

Now I can pass pf around, calling it with appropriate values.

I’m looking for a concise way of being able to define such a pf so that it can have a state. Say a counter of how many times it has been called. One way is this:

var counter = 0
val pf: PartialFunction[String, Unit] = {case s => counter +=1; println(s)}

What I don’t like here is that it is not concise and the state is exposed.

Answer 1

val pf: PartialFunction[String, Unit] = {
    var counter = 0;
    {case s =>  {
            println(counter + s)
            counter +=1
        }
    }
}