Adrian M. DevAndArtist

Property Delegates

The original proposal: https://github.com/DougGregor/swift-evolution/blob/property-delegates/proposals/NNNN-property-delegates.md

What is proposed?

A user can create custom property delegates that allow a var declaration to decide how to implement the storage.
The original proposal want to use a new identifier space, prefixed by $, to uniquely identify a property delegate from the computed and non-prefixed main property.

Application Development Techniques

Drivable UI

@dynamicMemberLookup
struct DriverFor<Base> {
 var base: Base

import UIKit

protocol ViewComponent : AnyObject {
  ///
  func isAncestor(of descendant: Self) -> Bool

  ///
  func isDescendant(of ancestor: Self) -> Bool

func ?? <T>(_ optional: T?, _ trap: @autoclosure () -> Never) -> T {
	switch optional {
	case .some(let value):
		return value
	case .none:
		trap()
	}
}

A layout guide for iOS 10 that is very similar to the safeAreaLayoutGuide from iOS 11.

extension UIView {
	///
	private final class LayoutGuide : UILayoutGuide {}
	
	///
	var guardedAreaLayoutGuide: UILayoutGuide {
		if #available(iOS 11, *) {

	public struct Unique<Key, Value>: Hashable where Key: Hashable {

	public enum KeyVariant {
	case key(Key)
	case keyPath(KeyPath<Value, Key>)
	case closure((Value) -> Key)

	internal func _key(for value: Value) -> Key {
	switch self {
	case .key(let key):

	class Ref {
	weak var obj: Obj? {
	didSet { print("didSet", obj as Any) }
	}
	}

	class Obj {
	weak var ref: Ref?

	func unlink(from ref: Ref) {

	protocol ValueContainer {
	associatedtype Value
	var value: Value { get }
	init(_ value: Value)
	}

	extension ValueContainer where Self : Equatable, Value : Equatable {
	static func == (lhs: Self, rhs: Self) -> Bool {
	return lhs.value == rhs.value
	}

	import RxSwift

	public final class DisposeCache<Key>
	: ExpressibleByDictionaryLiteral where Key : Hashable {
	///
	private var lock = NSRecursiveLock()

	///
	private var storage: [Key: Disposable]

	import Darwin
	import UIKit

	protocol _LoggerDelegate : AnyObject {
	///
	func logger(_ logger: Logger, received newString: String)
	}

	final class Logger {
	///