Protocol and init argument - swift

Question

An ex-collegue left a game uncomplete and undocumented.
When reading his code I found:
protocol EnemyMovement {
func forward(speedPercent: Int)
func reverse(speedPercent: Int)
func left(speedPercent: Int)
func right(speedPercent: Int)
}
protocol Enemy {
var name: String {get set}
var enemyMovement: EnemyMovement {get set}
init (name: String, enemyMovement: EnemyMovement)
}
class EnemyInstance: Enemy {
var name = "No enemy Name"
var enemyMovement: EnemyMovement
required init (name: String, enemyMovement: EnemyMovement) {
self.name = name
self.enemyMovement = enemyMovement
//...
}
I could not found a concrete instance of EnemyInstance, but if it's quite clear how to pass the name string, I don't understand how is EnemyMovement supposed to be passed.
var enemy = EnemyInstance(name: "zombie", enemyMovement?...)
Any idea?

Answer 1

Since parameter has to be of type conforming to EnemyMovement, including these methods, you have to pass this object. So, you can try to create example struct
struct Movements: EnemyMovement {
func forward(speedPercent: Int) {
print(speedPercent)
}
func reverse(speedPercent: Int) {
print(speedPercent)
}
func left(speedPercent: Int) {
print(speedPercent)
}
func right(speedPercent: Int) {
print(speedPercent)
}
}
now as parameter for EnemyInstance initializer pass new instance of Movements
var enemy = EnemyInstance(name: "zombie", enemyMovement: Movements())
then you can call some method on enemyMovement property of your class and code inside this certain method gets executed (in this case it should print speedPercent)
required init (name: String, enemyMovement: EnemyMovement) {
self.name = name
self.enemyMovement = enemyMovement
enemyMovement.forward(speedPercent: 2) // prints 2
}