Revisiting types in Kotlin - functions and collections

collections.kt

// fun <T, R> Iterable<T>.map(transform: (T) -> R): List<R>

// fun <T> Iterable<T>.filter(predicate: (T) -> Boolean): List<T>

fun main(args: Array<String>) {
    val immutable = listOf(1, 2, 3, 4, 5)
    // immutable.add(6)
    val mutable = mutableListOf(1, 2, 3, 4, 5)
    mutable.add(6)
    val otherElements = mutable.map({ value ->
                            value + 1
                        }).filter {
                            it % 2 == 0
                        }
    // otherElements.add(6)
    println(otherElements);
}