swift @indirect property wrapper

indirect.swift

@dynamicMemberLookup
@propertyWrapper
enum Indirect<T> {
  indirect case wrapped(T)

  var wrappedValue: T {
    get { switch self { case .wrapped(let x): return x } }
    set { self = .wrapped(newValue) }
  }

  init(wrappedValue: T) {
    self = .wrapped(wrappedValue)
  }
  
  subscript<U>(dynamicMember keyPath: KeyPath<T, U>) -> U {
    wrappedValue[keyPath: keyPath]
  }
}

extension Indirect: Codable where T: Codable {}
extension Indirect: Sendable where T: Sendable {}