Generic Classes & Functions in Kotlin

// Generic class
class Box<T>(val value: T) {
    fun get(): T = value
}

val intBox = Box(42)
val stringBox = Box("Hello")

// Generic function
fun <T> singletonList(item: T): List<T> {
    return listOf(item)
}

val list = singletonList("item")

// Multiple type parameters
class Pair<A, B>(val first: A, val second: B) {
    fun swap(): Pair<B, A> = Pair(second, first)
}

// Type constraints
fun <T : Comparable<T>> max(a: T, b: T): T {
    return if (a > b) a else b
}

// Multiple constraints with where
fun <T> process(value: T)
    where T : CharSequence,
          T : Comparable<T> {
    println("Length: ${value.length}")
    println("Value: $value")
}