Building Skype for Business in Swift

Slides from a "Talking Tech with Microsoft" presentation I gave in Stockholm.

Transcript

4. • Safety, missing values • Convenience, boilerplate • Powerful, expressive helpers
5. Option Types for safety
6. if isConference && !subject.isEmpty { title = subject }
7. if isConference { title = subject }
8. Value of optional type ‘String?’ not unwrapped if isConference { title = subject }
9. if isConference, let subject = subject { title = subject }
10. let remotePersonKey = conversation.remoteParticipant?.person?.key
11. × ( ) ∶ → → , ↦ None Some ( ʹ) if = None if = Some ʹ ῲ ῳ ῴ ? ? × ( ) ∶ → → , ↦ None ( ʹ) if = None if = Some ʹ ῲ ῳ ῴ ? ? ?
12. Generics, Higher Order Functions, Type Inference to deal with boilerplate
13. class MyExamplePerson: NSObject, IPAEventListener { let person: IPAExamplePerson init(person: IPAExamplePerson) { self.person = person super.init() // Register for events self.person.registerListener(self) } deinit { // Deregister for events self.person.deregisterListener(self) } // Check if the IPAPerson has updated it's display name @objc func onEvent(event: AnyObject!) { // Verify that it's the correct kind of event guard let personEvent = event as? IPAExamplePersonEvent else { return } // Verify that the event is for an updated property guard personEvent.type == .PropertiesChanged else { return } // Check that it was the expected property that changed if personEvent.isPropertyChanged(.DisplayName) { // get the new display name } } }
14. typealias Callback = (Event) -> () private typealias Predicate = (Event) -> Bool private init( source: IPAEventListenerRegistry, predicatesAndCallbacks: [([Predicate], Callback)] )
15. init(person: IPAExamplePerson) { self.person = person self.displayNameListener = EventListener(source: person, predicatesAndCallbacks: [ ([ // Event verifications { event in event.type == .PropertiesChanged }, { event in event.isPropertyChanged(.DisplayName) } ], // Callback { _ in // get the new display name } ) ] ) }
16. private init( source: IPAEventListenerRegistry, predicatesAndCallbacks: [([Predicate], Callback)] ) private convenience init<T>( source: IPAEventListenerRegistry, transformableAndCallbacks: [(T, Callback)], transform: (T -> [Predicate]) )
17. extension EventListener where E: PropertyEvent { convenience init( source: IPAEventListenerRegistry, forPropertyChange: (E.Property, EmptyCallback) ... ) } protocol PropertyEvent: Event { associatedtype Property func isPropertyChanged(property: Property) -> Bool }
18. init(person: IPAExamplePerson) { self.person = person self.displayNameListener = EventListener(source: person, forPropertyChanges: (.DisplayName, { // get the new display name }) ) }
19. Expressive helpers, leveraging helpers, which is leveraging other helpers
20. KVO
21. KVO "Traditional" KVO Owner Target
22. Owner Target {} KVO KVO with a closure callback
23. Owner Target {} KVO 1-way KVO Bindings (automatically updating one value when another value changes)
24. Owner {} KVO Target (collection) 1-way KVO Bindings on collections (automatically updating one collection when elements are added/removed in another collection)
25. Owner KVO Target (collection) 1-way KVO Bindings over collections
26. Owner KVO Target (collection) {} KVO KVO KVO KVO KVO {} 1-way KVO Bindings over collections (closure callbacks when elements are added/removed from the observed collection or when elements within the collection updates)
27. observe(sessionManager, forCollectionKeyPath: "session.conversationManager.conversations", elementKeyPath: "chat.hasUnreadMessages") { // Badge the dock icon }
28. Q & A