Defining a Map from String to Function in Scala

Question

I am trying to define a Map literal with key: String, value: (Any)=>String. I tried the following, but get a syntax error:

def foo(x         


        

Answer 1

If I let the compiler infer it I seem to get an illegal type:

scala> val m = Map("hello" -> foo _, "goodbye" -> bar _)
m: scala.collection.immutable.Map[java.lang.String,(Boolean with Int) => String] =
                Map((hello,), (goodbye,))

scala> m("hello")(8)
:9: error: type mismatch;
 found   : Int(8)
 required: Boolean with Int
       m("hello")(8)
scala> var q = new Boolean with Int
:5: error: illegal inheritance from final class Boolean
       var q = new Boolean with Int

Anyway, what you want is not the type Any but a generic of "any type" which is _:

scala> val mm = Map[String, (_) => String]("hello" -> foo _, "goodbye" -> bar _)
mm: scala.collection.immutable.Map[String,Function1[_, String]] =
               Map((hello,), (goodbye,))

I just posted a question about how to invoke such functions because I don't actually know.