Stringly-typed API Replacement

stringly-typedAPI

// MARK: - Use Enums for getting/setting User Defaults

protocol KeyNameSpaceable {
    func namespaced<T: RawRepresentable> (_ key: T) -> String
}

extension KeyNameSpaceable {
    func namespaced<T: RawRepresentable> (_ key: T) -> String {
        
        return "\(Self.self).\(key.rawValue)"
    }
}

protocol BoolDefaultSettable: KeyNameSpaceable {
    associatedtype BoolKey: RawRepresentable
}

extension BoolDefaultSettable where BoolKey.RawValue == String {
    func set(_ value: Bool, forKey key: BoolKey) {
        let key = namespaced(key)
        UserDefaults.standard.set(value, forKey: key)
    }
    
    func bool(forKey key: BoolKey) -> Bool {
        let key = namespaced(key)
        
        return UserDefaults.standard.bool(forKey: key)
    }
}

extension UserDefaults {
    struct Onboarding: BoolDefaultSettable {
        enum BoolKey : String {
            case hasRunBefore
            case hasShownOnboarding
            case isCheckingLocations
            case hasScannedPhotoLibrary
       }
    }
    
    struct Switches: BoolDefaultSettable {
        enum BoolKey : String {
            case photosSwitch
            case facebookSwitch
            case twitterSwitch
            case israelSwitch
            case chinaSwitch
            case crimeaSwitch
            case kosovoSwitch
            case purchasesState
        }
    }
}

Ideally, in extension BoolDefaultSettable where BoolKey.RawValue == String the functions would be static functions, so the calls in code would be something like
UserDefaults.Onboarding.set(true, forKey: .hasScannedPhotoLibrary) instead of
UserDefaults.Onboarding().set(true, forKey: .hasScannedPhotoLibrary)