Scala function pointer

Question

Google didn't help me with this question, I hope that doesn't mean it is not possible:

In my class I want to have a method that has a signature defined, but the body is not defined (method1)

There will be many defined methods that satisfy this signature (impl1, impl2, impl3)

When I initialise the object, I will then choose (based on some criteria) which method implementation impl1, impl2, impl3 to assign to the function pointer method1

Basically I'm asking how I can have a function pointer that can point to any function satisfying its signature.

EDIT:

So, it turns out it is actually very straight forward:

var method: Int => Int = (x => x+1)

method = (x => x-1)
method = (x => x*2)
etc...

My problem before was that I was using "val" or "def" to define "method"

Not sure why this wasn't suggested directly. Many people favoured the way of having the function as a parameter to some secondary class then initialise that class with a specific implementation. Maybe there is something that I'm missing.

EDIT 2: I realise now that I didn't get the answer I was looking for because I didn't word my question properly, I should have said that I wanted "delegate" behaviour as it is in C#.

Answer 1

In Scala, functions are objects, so you can do:

class Foo(val func : Int => Int){
}
object Main{
    def main(args: Array[String]) {
        val foo1=new Foo(x => x + 1)
        val foo2=new Foo(x => x + 2)
        val foo3=new Foo(x => x + 3)
        println(foo1.func(10)) // Prints 11
        println(foo2.func(10)) // Prints 12
        println(foo3.func(10)) // Prints 13
    }
}