AssociatedTypes.swift

//: Playground - noun: a place where people can play

import UIKit
import RxSwift

protocol ListSource {
  associatedtype ItemT
  
  func getItems(index: Int) -> [ItemT]
}

class ActualSource: ListSource {
  typealias ItemT = String
  
  func getItems(index: Int) -> [String] {
    return ["Hallo", "Na"]
  }
}

let l: Array<String>

class Storage<T, ListSourceT: ListSource> where ListSourceT.ItemT == T {
  let ls: ListSourceT
  
  init(_ listSource: ListSourceT) {
    ls = listSource
    let items: [T] = ls.getItems(index: 2)
    print(items.count)
  }
}

let actualSource = ActualSource()
let stringStorage = Storage(actualSource)