Kotlin prepend element

Issue

I am searching for Kotlin alternative to:
(cons 1 '(2 3)) in lisp or
1 : [2, 3] in haskell or
1 :: List(2, 3) in scala,
(which all result in sth like [1, 2, 3])
so I can prepend an element to a List<T> (or any other list you can offer).

It will also be fine if one could provide O(1) head and tail Kotlin alternatives (I've found just first())

Solution

Any class which implements Deque will suitable for you, for example LinkedList:

val linkedList = LinkedList(listOf(2, 3))
linkedList.push(1)
println(linkedList) // [1, 2, 3]

Creating lists throught constructor LinkedList(listOf(2, 3)) in many places can be annoying, so feel free to write factory method:

fun <T> linkedListOf(vararg elements: T): LinkedList<T> {
    return LinkedList<T>(elements.toList())
}

// Usage:
val list = linkedListOf(2, 3)
list.push(1)
println(list) // [1, 2, 3]

Answered By - Ruslan