Dancing with Dinosaurs: Objective-C and Swift Interop

In this presentation, we meet at an old friend (Objective-C) and how it interacts with its new friend (Swift).

From making our Objective-C code work great with Swift, to making our Swift code available in Objective-C as well; covering things from nullability and (advanced) renaming to option sets and generics.

… and the story behind me “meeting” the Swift programming language.

Transcript

1. DANCING WITH DINOSAURS 1 — @basthomas, NSSpain, November 2021
2. DANCING WITH DINOSAURS OBJECTIVE-C & SWIFT INTEROP 2 — @basthomas, NSSpain, November 2021
3. JUNE 2, 2014 3 — @basthomas, NSSpain, November 2021
4. OBJECTIVE-C 4 — @basthomas, NSSpain, November 2021
5. ... WITHOUT THE C 5 — @basthomas, NSSpain, November 2021
6. ▸ The Netherlands ▸ Germany ▸ The Netherlands (ish) ▸ Spain (ish) ▸ Ireland ▸ Rotterdam, the Netherlands 6 — @basthomas, NSSpain, November 2021
7. BAS ▸ XING Mobile Releases & Platform Team ▸ Apple macOS Accessibility ▸ WeTransfer 7 — @basthomas, NSSpain, November 2021
8. BAS ▸ XING Mobile Releases & Platform Team Objective-C & Swift ▸ Apple macOS Accessibility Objective-C ▸ WeTransfer Swift 8 — @basthomas, NSSpain, November 2021
9. OBJECTIVE-C & SWIFT INTEROP 9 — @basthomas, NSSpain, November 2021
10. I: AUDITING OBJECTIVE-C FOR SWIFT 10 — @basthomas, NSSpain, November 2021
11. GENERATED INTERFACES 11 — @basthomas, NSSpain, November 2021
12. 12 — @basthomas, NSSpain, November 2021
13. NULLABILITY 13 — @basthomas, NSSpain, November 2021
14. #import <Foundation/Foundation.h> @interface BTBWatch : NSObject - (NSInteger)currentHour; - (NSDate *)currentDate; - (BOOL)setTimeWithHours:(NSInteger)hours minutes:(NSInteger)minutes seconds:(NSInteger)seconds error:(NSError **)error; - (void)printCurrentTime; @property (nonatomic) NSString *strapType; @property (nonatomic, readonly) NSArray *functions; @end 14 — @basthomas, NSSpain, November 2021
15. open class BTBWatch : NSObject { open func currentHour() -> Int open func currentDate() -> Date! open func setTimeWithHours(_ hours: Int, minutes: Int, seconds: Int) throws open func printCurrentTime() open var strapType: String! open var functions: [Any]! { get } } 15 — @basthomas, NSSpain, November 2021
16. NS_ASSUME_NONNULL_BEGIN @interface BTBWatch : NSObject /// Interface here @end NS_ASSUME_NONNULL_END 16 — @basthomas, NSSpain, November 2021
17. open class BTBWatch : NSObject { open func currentHour() -> Int open func currentDate() -> Date open func setTimeWithHours(_ hours: Int, minutes: Int, seconds: Int) throws open func printCurrentTime() open var strapType: String open var functions: [Any] { get } } 17 — @basthomas, NSSpain, November 2021
18. @property (nonatomic, nullable) NSString *strapType; 18 — @basthomas, NSSpain, November 2021
19. open var strapType: String? 19 — @basthomas, NSSpain, November 2021
20. (RE)NAMING 20 — @basthomas, NSSpain, November 2021
21. - (NSInteger)currentHour; - (NSDate *)currentDate; @property (nonatomic, readonly) NSInteger currentHour; @property (nonatomic, readonly) NSDate *currentDate; 21 — @basthomas, NSSpain, November 2021
22. open func currentHour() -> Int open func currentDate() -> Date open var currentHour: Int { get } open var currentDate: Date { get } 22 — @basthomas, NSSpain, November 2021
23. open func setTimeWithHours(_ hours: Int, minutes: Int, seconds: Int) 23 — @basthomas, NSSpain, November 2021
24. - (void)setTimeWithHours:(NSInteger)hours minutes:(NSInteger)minutes seconds:(NSInteger)seconds error:(NSError **)error NS_SWIFT_NAME(setTime(hours:minutes:seconds:)); 24 — @basthomas, NSSpain, November 2021
25. open func setTime(hours: Int, minutes: Int, seconds: Int) throws 25 — @basthomas, NSSpain, November 2021
26. ENUMS AND OPTION SETS 26 — @basthomas, NSSpain, November 2021
27. NS_ASSUME_NONNULL_BEGIN const NSString *patekPhilippe; const NSString *aLangeSoehne; const NSString *omega; const NSString *meisterSinger; NS_SWIFT_NAME(Watch) @interface BTBWatch : NSObject // ... 27 — @basthomas, NSSpain, November 2021
28. public let patekPhilippe: String public let aLangeSoehne: String public let omega: String public let meisterSinger: String 28 — @basthomas, NSSpain, November 2021
29. NS_ASSUME_NONNULL_BEGIN NS_SWIFT_NAME(Watch.Brand) typedef NSString * WatchBrand NS_TYPED_EXTENSIBLE_ENUM; const WatchBrand patekPhilippe; const WatchBrand aLangeSoehne; const WatchBrand omega; const WatchBrand meisterSinger; NS_SWIFT_NAME(Watch) @interface BTBWatch : NSObject // ... 29 — @basthomas, NSSpain, November 2021
30. extension Watch { public struct Brand : Hashable, Equatable, RawRepresentable { public init(_ rawValue: String) public init(rawValue: String) } } extension Watch.Brand { public static let patekPhilippe: Watch.Brand public static let aLangeSoehne: Watch.Brand public static let omega: Watch.Brand public static let meisterSinger: Watch.Brand } 30 — @basthomas, NSSpain, November 2021
31. extension Watch.Brand { public static let mondaine: Watch.Brand } 31 — @basthomas, NSSpain, November 2021
32. typedef NS_OPTIONS(NSInteger, BTBComplication) { BTBComplicationDateWindow = 1 << 0, BTBComplicationPowerReserveIndicator = 1 << 1, BTBComplicationChronograph = 1 << 2 } NS_SWIFT_NAME(Watch.Complication); 32 — @basthomas, NSSpain, November 2021
33. extension Watch { public struct Complication : OptionSet { public init(rawValue: Int) public static var dateWindow: Watch.Complication { get } public static var powerReserveIndicator: Watch.Complication { get } public static var chronograph: Watch.Complication { get } } } 33 — @basthomas, NSSpain, November 2021
34. LIGHTWEIGHT GENERICS 34 — @basthomas, NSSpain, November 2021
35. @property (nonatomic, readonly) NSArray *functions; open var functions: [Any] { get } 35 — @basthomas, NSSpain, November 2021
36. @property (nonatomic, readonly) NSArray<NSString *> *functions; open var functions: [String] { get } 36 — @basthomas, NSSpain, November 2021
37. RECAP ▸ Generated Interfaces ▸ Nullability ▸ (Re)naming ▸ Enums and option sets ▸ Lightweight generics 37 — @basthomas, NSSpain, November 2021
38. II: EXPOSING SWIFT TYPES TO OBJECTIVE-C 38 — @basthomas, NSSpain, November 2021
39. POWERFUL ENUMS 39 — @basthomas, NSSpain, November 2021
40. enum Bookcase: String { case billy case hemnes case kallax } Bookcase.billy.rawValue // "billy" 40 — @basthomas, NSSpain, November 2021
41. // Bookcase.h // Nothing to be seeen here... 41 — @basthomas, NSSpain, November 2021
42. VALUE TYPE NULLABILITY 42 — @basthomas, NSSpain, November 2021
43. class Library { let bookcases: [Bookcase?] init(bookcases: [Bookcase?]) { self.bookcases = bookcases } } Library(bookcases: [.billy, nil, .kallax, .kallax]) 43 — @basthomas, NSSpain, November 2021
44. A SWIFT-FIRST APPROACH 44 — @basthomas, NSSpain, November 2021
45. DON'T LIMIT YOURSELF 45 — @basthomas, NSSpain, November 2021
46. RECAP ▸ Powerful enums ▸ Value type nullability ▸ Swift-first 46 — @basthomas, NSSpain, November 2021
47. III: ADVANCED INTEROPABILITY 47 — @basthomas, NSSpain, November 2021
48. SWIFTIER OBJECTIVE-C 48 — @basthomas, NSSpain, November 2021
49. #if defined(__cplusplus) #define let auto const #else #define let const __auto_type #endif #if defined(__cplusplus) #define var auto #else #define var __auto_type #endif 49 — @basthomas, NSSpain, November 2021
50. map, forEach, flatMap, reduce 50 — @basthomas, NSSpain, November 2021
51. ASYNC-AWAIT 51 — @basthomas, NSSpain, November 2021
52. "IT JUST WORKS" SE-0297 52 — @basthomas, NSSpain, November 2021
53. - (void)fetchShareParticipantWithUserRecordID:(CKRecordID *)userRecordID completionHandler:(void (^)(CKShareParticipant * _Nullable, NSError * _Nullable))completionHandler; func fetchShareParticipant( withUserRecordID userRecordID: CKRecord.ID, completionHandler: @escaping (CKShare.Participant?, Error?) -> Void ) func fetchShareParticipant( withUserRecordID userRecordID: CKRecord.ID ) async throws -> CKShare.Participant 53 — @basthomas, NSSpain, November 2021
54. @objc func perform(operation: String) async -> Int { ... } - (void)performWithOperation:(NSString * _Nonnull)operation completionHandler:(void (^ _Nullable)(NSInteger))completionHandler; 54 — @basthomas, NSSpain, November 2021
55. - (NSProgress *)takesALongTimeWithCompletionHandler: (void (^)(MyResult * _Nullable, NSError * _Nullable))completionHandler; 55 — @basthomas, NSSpain, November 2021
56. GENERICS 56 — @basthomas, NSSpain, November 2021
57. @interface Queue<__covariant ObjectType> : NSObject - (void)enqueue:(ObjectType)value; - (ObjectType)dequeue; @end 57 — @basthomas, NSSpain, November 2021
58. RECAP ▸ Swiftier Objective-C ▸ Async-await ▸ Generics 58 — @basthomas, NSSpain, November 2021
59. ¡GRACIAS! @BASTHOMAS 59 — @basthomas, NSSpain, November 2021
60. REFERENCES ▸ https://developer.apple.com/videos/play/wwdc2020/10680/ ▸ https://basbroek.nl/objc-swift-interop-auditing ▸ https://basbroek.nl/there-and-back-again ▸ https://pspdfkit.com/blog/2017/even-swiftier-objective-c/ ▸ https://github.com/apple/swift-evolution/blob/main/proposals/ 60 — @basthomas, NSSpain, November 2021