LinkedList.swift

// Linked list using optionals and enums with associated values.
// See https://medium.com/@andre_videla/total-programming-in-swift-526508c12a74

import Foundation

class Node<Elem> {
    init(withElement elem: Elem, attachToList tail: List<Elem>) {
        self.elem = elem
        self.tail = tail
    }
    let elem: Elem
    private let tail: List<Elem>
}

 enum List<Elem> {
    case Empty
    indirect case Node(Elem, List<Elem>)
}

func count<Elem>(list: List<Elem>) -> Int {
    switch list {
    case .Empty: return 0
    case let .Node(_, rest): return 1 + count(list: rest)
    }
}

func print(list: List<Int>) {
    switch list {
    case .Empty: print()
    case let .Node(elem, rest): do {
        print("\(elem) ", terminator:"")
        print(list:rest)
    }
    }
}

var myList = List<Int>.Node(1, .Empty)
myList = List<Int>.Node(2, myList)
myList = List<Int>.Node(3, myList)

let numberOfItems = count(list: myList)
print("My list has \(numberOfItems) items!")
print("Here are the items: ", terminator:"")
print(list: myList)