rshepherd

public class IdentitySwitch {
  public static void main(String[] args) {
    String s = "unchanged";
    System.out.println(s);
    foo(s);
    System.out.println(s);
  }
  
  public void foo(String s) {
    s = "changed"

rshepherd

class DoublePointer {
  String s;
  public DoublePointer(String s){
    this.s = s;
  }
}

public class IdentitySwitch {
  public static void main(String[] args) {
    DoublePointer dp = new DoublePointer("unchanged");

rshepherd

class SkipList {

  data class Node<Value>(val id: Value, val children: MutableList<Node<Value>> = mutableListOf())

  abstract class Value<T>(val value: T) {
    abstract fun distance(other: T): Int
  }

  class IntValue(id: Int) : Value<Int>(id) {
    override fun distance(other: Int): Int = kotlin.math.abs(this.value - other)

rshepherd

// A common example of a functor in Scala is the Option type.
// In Scala, Option is a functor because it provides the map method, which allows you to
// apply a function to the value inside an Option while preserving its structure.
val someNumber: Option[Int] = Some(3)
val incremented: Option[Int] = someNumber.map(_ + 1)
println(incremented) // Value transformed while structure is preserved

// Similarly List is a Functor
val numbers = List(1, 2, 3)
val doubled = numbers.map(_ * 2)