(1) What do we lose switching from imperative to declarative? (2)When do you really need this ability to (re)build your subview hierarchy at will, at runtime?
UIKit extension UIResponder { var fieldsController: FieldsController? { if let c = self as? FieldsController { return c } if let c = next as? FieldsController { return c } return next?.fieldsController } } github.com/radianttap/Fields
SwiftUI https://developer.apple.com/videos/play/wwdc2019/216/?time=3160 “And then we can use the navigationBarTitle modifier to produce that large beautiful title for our form. Now this modifier is a little bit special. It provides information that’s able to be interpreted by a NavigationView ancestor. …this is an example of one that flows information upwards using something called preferences.” SwiftUI Essentials