The Old and the New

There is little questioning that Swift is where we’re headed, but for the time being it’s important to be pragmatic about interoperability with Cocoa and existing code is in order to remain productive.

This talk is about how our team uses Swift, how we approach new language features and functional patterns (the new), and how we deal with both Cocoa and other existing code (the old).

Transcript

1. Olá! David Rönnqvist SwiftAveiro 2016
2. : really not that long at all A long* time ago… *
4. & The Old The New SwiftAveiro 2016 The New
5. Thinking & Ideas
6. ! "
7. # ☹
8. if removedMessageIndexes.count > 0 { mutableArrayValueForKey("messages") .removeObjectsAtIndexes(removedMessageIndexes) }
9. no gain but also no loss
12. Everything Objects ⊈
13. AnyBidirectionalCollection AnyBidirectionalIndex AnyForwardCollection AnyForwardIndex AnyRandomAccessCollection AnyRandomAccessIndex AnySequence Array ArraySlice AutoreleasingUnsafeMutablePointer Bool COpaquePointer CVaListPointer Character ClosedInterval CollectionOfOne ContiguousArray Dictionary DictionaryGenerator DictionaryIndex DictionaryLiteral Double EmptyCollection EmptyGenerator EnumerateGenerator EnumerateSequence FlattenBidirectionalCollection FlattenBidirectionalCollectionIndex FlattenCollection FlattenCollectionIndex FlattenGenerator FlattenSequence Float GeneratorOfOne GeneratorSequence HalfOpenInterval IndexingGenerator Int Int16 Int32 Int64 Int8 JoinGenerator JoinSequence LazyCollection LazyFilterCollection LazyFilterGenerator LazyFilterIndex LazyFilterSequence LazyMapCollection LazyMapGenerator LazyMapSequence LazySequence ManagedBufferPointer Mirror MutableSlice ObjectIdentifier PermutationGenerator Range RangeGenerator RawByte Repeat ReverseCollection ReverseIndex ReverseRandomAccessCollection ReverseRandomAccessIndex Set SetGenerator SetIndex Slice StaticString StrideThrough StrideThroughGenerator StrideTo StrideToGenerator String String.CharacterView String.CharacterView.Index String.UTF16View String.UTF16View.Index String.UTF8View String.UTF8View.Index String.UnicodeScalarView String.UnicodeScalarView.Generator String.UnicodeScalarView.Index UInt UInt16 UInt32 UInt64 UInt8 UTF16 UTF32 UTF8 UnicodeScalar Unmanaged UnsafeBufferPointer UnsafeBufferPointerGenerator UnsafeMutableBufferPointer UnsafeMutablePointer UnsafePointer Zip2Generator Zip2Sequence Bit FloatingPointClassification ImplicitlyUnwrappedOptional Mirror.AncestorRepresentation Mirror.DisplayStyle Optional PlaygroundQuickLook Process UnicodeDecodingResult AnyGenerator NonObjectiveCBase ManagedProtoBuffer ManagedBuffer VaListBuilder Structs Enums Classes
16. Immutability & Pure Functions
17. less to consider
19. as much as we can but no more
20. %
21. requiring the least specific type
22. no client should be forced to depend on methods it does not use “interface-segregation principle”
23. “kärt barn har många namn” something which is liked or well though of, is often referred to by many different names
24. protocol OcclusionReporting: NSObjectProtocol { var occlusionState: NSApplicationOcclusionState { get } } extension NSApplication: OcclusionReporting {}
25. partial functions
26. &
27. arguments
28. var username: String? var password: String? func signIn() func signIn(username: String, password: String) vs.
29. T?
30. NS_REFINED_FOR_SWIFT
31. higher order functions
32. Everything Objects ⊈
33. higher order functions separating context from specifics
34. ([A], (A  B))  [B] 1 2 3 4 5 6 7 8 1 4 9 16 25 36 49 64 square square square square square square square square
35. ([A], (A  Bool))  [A] 1 2 3 4 5 6 7 8 isPrime isPrime isPrime isPrime isPrime isPrime isPrime isPrime 3 5 7 2
37. composition
38. object composition function composition &
39. ( )( ) = ( ( ))
40. infix operator ⚬ { associativity left precedence 160 } func ⚬ <A, B, C>(f: B -> C, g: A -> B) -> (A -> C) { return { x in f(g(x)) } }
41. The point is not to mimic the syntax of another language
42. higher order functions loops
43. what? vs. how?
44. declarative vs. imperative
45. scaling
46. ([A], B, ((B, A)  B))  B 0 1 2 3 4 5 7 8 + 1 + 5 + 12 + 20 + 23 + 28 + 30
47. A B C D E F G H 1 2 3 4 5 6 7 0 enumerate
48. A B C D E F G H 1 4 9 16 25 36 49 64 zip
49. 1 2 3 4 5 6 7 0 range
50. 3 6 9 12 15 18 21 24 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0.0 stride
51. '
52. measure!
53. Mutation & Side-effects
54. expectations
55. private implementations
56. separating data separating logic &
57. separating data
60. for (dot, config) in zip(dots, dotConfigs) { let move = CAKeyframeAnimation(keyPath: "position") move.path = circularPath() move.timingFunction = config.rotationTimingFunction let scale = CAKeyframeAnimation(keyPath: “transform.scale") scale.values = config.scaleValues scale.keyTimes = config.scaleKeyTimes scale.timingFunctions = config.scalingTimingFunctions let group = CAAnimationGroup() group.duration = 1.4 group.repeatCount = HUGE group.animations = [move, scale] dot.addAnimation(group, forKey: nil) }
61. separating logic
62. func testChange_whenRemovingMiddleElement_shouldLeaveMiddleEmpty() { let (slots, _) = setupTestData("A B C", history: "ABC") let (newSlots, change) = slots.removing("B") XCTAssertEqual(newSlots.testSummary, "A _ C") XCTAssertEqual(change, SlotChange.Removal(at: 1)) } // ... func testAddingElementTwice_shouldNotTriggerAnyKVO() { sut.add("A") expectNoObservationFor { sut.add("A") } } func testAddingElement_whenFullAndMiddleIsOldest_shouldHaveKVOReplacementAtMiddle() { sut.add("A") sut.add("B") sut.add("A") sut.add("C") expectObservationFor(.Replacement(at: 1)) { sut.add("D") } }
64. A language that doesn't affect the way you think about programming, is not worth knowing. Alan Perlis first recipient of the Turing Award “ ”
65. Thanks for listening! David Rönnqvist @davidronnqvist http://ronnqvi.st
66. Questions SwiftAveiro 2016