struct Origin {
  var city: String

  init(city: String = "") {
    self.city = city
  }
}

struct Person {
  var name: String
  var origin: Origin

  init(name: String = "", origin: Origin = Origin()) {
    self.name = name
    self.origin = origin
  }
}

struct OriginLenses {
  static let city = Lens(get: { $0.city }, set: { (inout origin: Origin, city) in
    origin.city = city
  })
}

struct PersonLenses {
  static let name = Lens(get: { $0.name }, set: { (inout person: Person, name) in
    person.name = name
  })

  static let origin = Lens(get: { $0.origin }, set: { (inout person: Person, origin) in
    person.origin = origin
  })
}

var person = Person(name: "Felix", origin: Origin(city: "Berlin"))
person = set(PersonLenses.name, person, "Robb")
get(PersonLenses.name, person) // == "Robb"

let composed = PersonLenses.origin >>> OriginLenses.city
person = set(composed, person, "New York")
get(composed, person) // == "New York"

struct Adapters {
  static let origin = DictionaryAdapter(specification: [
    "city_name": map(OriginLenses.city, StringToAnyObjectValueTransformers)
  ], dictionaryTansformer: DictionaryToAnyObjectValueTransformers, value: Origin())

  static let person = DictionaryAdapter(specification: [
    "name": map(PersonLenses.name, StringToAnyObjectValueTransformers),
    "origin": map(PersonLenses.origin, origin)
  ], dictionaryTansformer: DictionaryToAnyObjectValueTransformers, value: Person())
}

let adapter: DictionaryAdapter<Key, Value, TransformedValue, Error> = fix { adapter in
  // use `adapter` to reference the currently created adapter
}

let adapter = Adapters.person

var person = Person(name: "Seb", origin: Origin(city: "Berlin"))
var data = adapter.transform(person)
// == .Success(Box([ "name": "Seb", "origin": [ "city_name": "Berlin" ] ]))

adapter.reverseTransform(data.value!)
// == .Success(Box(person))