KeyPath<Root, Value> example

KeyPath.swift

struct Player: CustomDebugStringConvertible {
  var number: Int
  var name: String
  
  var debugDescription: String { "Player {number=\(number), name= \(name)}" }
}

func keyPaths<R, T>(_ base: R, kp: KeyPath<R, T>) {
  let value = base[keyPath: kp]
  print("kp value: \(value)")
}

var kobe = Player(number: 8, name: "Bryant")

keyPaths(kobe, kp: \.number) // kp value: 24
keyPaths(kobe, kp: \.name) // kp value: Bryant