SHList

let list = HList("Hello", 42, true)

list.head           // => "Hello"
list.tail.head      // => 42
list.tail.tail.head // => true

list.count           // => 3
list.tail.count      // => 2
list.tail.tail.count // => 2

list.asArray() // => ["Hello", 42, true] as [Any]

func f(a1: String, a2: Int, a3: Bool) -> String {
    "\(a1),\(a2),\(a3)"
}

list.apply(f) // => "Hello,42,true"