SlideShare a Scribd company logo

Swift 2.2 Design Patterns CocoaConf Austin 2016

Carl Brown
Carl Brown

The document discusses design patterns in Swift 2.2, highlighting their importance in software engineering and their specific implementations within the Cocoa framework. It covers various patterns such as the delegate pattern, observer pattern, and the singleton pattern, providing code examples and insights into their usage and advantages in Swift development. The text also emphasizes unique Swift features, such as value types, immutability, and separation of error handling.

Technology
1 of 100
Downloaded 15 times
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Swift 2.2 Design Patterns COCOACONF AUSTIN APRIL 2016 Skyline Credit: User:Argash [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons @CarlBrwn
Swift 2.2 Design Patterns COCOACONF AUSTIN APRIL 2016 Skyline Credit: User:Argash [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons @CarlBrwn
[:]? So, who is this idiot, anyway? INTRODUCTION @CarlBrwn
Swift 2.2 Design Patterns CocoaConf Austin 2016
These mean a lot of different things to different people. Hopefully they’re of some use to you. WIDELY RECOGNIZED, BUT NOT UNDISPUTED
These mean a lot of different things to different people. Hopefully they’re of some use to you. WIDELY RECOGNIZED, BUT NOT UNDISPUTED [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
So, Let’s talk about Swift (2.2 Version) PATTERNS ARE LANGUAGE SPECIFIC [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
So, Let’s talk about Swift (2.2 Version) & Cocoa PATTERNS ARE LANGUAGE (& FRAMEWORK) SPECIFIC [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8 
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift Patterns from Other Languages
Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift Patterns from Other Languages Interesting/Potential Swift-specific Patterns
 Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN 9  Cocoa is said to favor “Composition over Inheritance.” Delegation is one of the hallmarks of that strategy. UITableViewDataSource and UITableViewDelegate are examples. CLASSIC COCOA PATTERN
 Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN 9  Cocoa is said to favor “Composition over Inheritance.” Delegation is one of the hallmarks of that strategy. UITableViewDataSource and UITableViewDelegate are examples. CLASSIC COCOA PATTERN [:]? Eases Construction This is a big reason why we don’t have to use the “Factory Pattern” in Cocoa/ Swift
Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN IN SWIFT 10  var myDS : UITableViewDataSource? let myTVC = UITableViewController() let myTV = myTVC.tableView let num = myDS?.tableView(myTV, numberOfRowsInSection: 0) let firstHeader = myDS?.tableView?(myTV, titleForHeaderInSection: 0)
Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN IN SWIFT 10  var myDS : UITableViewDataSource? let myTVC = UITableViewController() let myTV = myTVC.tableView let num = myDS?.tableView(myTV, numberOfRowsInSection: 0) let firstHeader = myDS?.tableView?(myTV, titleForHeaderInSection: 0) 1 Test Delegate Optional The delegate itself must not be nil (check with ? and don’t (EVER) use !) 2 Test Method Exists Put ? after method call to test for @optional implementation
 Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN 11  In Cocoa, methods that produce errors take an NSError pointer parameter last parameter. In Swift 2, this is converted to a thrown ErrorType NEW IN SWIFT 2 - HOOKS INTO COCOA’S (NSError**)
 Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN 11  In Cocoa, methods that produce errors take an NSError pointer parameter last parameter. In Swift 2, this is converted to a thrown ErrorType NEW IN SWIFT 2 - HOOKS INTO COCOA’S (NSError**) [] Not JAva’s Throw try on each line that might throw catch for blocks
Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN IN SWIFT 12  - (BOOL)removeItemAtURL:(NSURL *)URL error:(NSError **)error { NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *URL = [NSURL fileURLWithPath:@"/path/to/file"]; NSError *error = nil; BOOL success = [fileManager removeItemAtURL:URL error:&error]; if (!success) { NSLog(@"Error: %@", error.domain); } }
Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN IN SWIFT 12  func removeItemAtURL(URL: NSURL) throws { let fileManager = NSFileManager.defaultManager() let URL = NSURL.fileURLWithPath("/path/to/file") do { try fileManager.removeItemAtURL(URL) } catch let error as NSError { print("Error: (error.domain)") } } - (BOOL)removeItemAtURL:(NSURL *)URL error:(NSError **)error { NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *URL = [NSURL fileURLWithPath:@"/path/to/file"]; NSError *error = nil; BOOL success = [fileManager removeItemAtURL:URL error:&error]; if (!success) { NSLog(@"Error: %@", error.domain); } }
 Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN 13  Key-Value Observing lets you observe any well-behaved Cocoa property (getter/setter). It works in Swift *As Long As* the target isKindOf: NSObject KVO IN SWIFT
Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14 
Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext)
Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext) override func observeValueForKeyPath(keyPath:String?, ofObject object: AnyObject?, change: [ String : AnyObject ]?, context: UnsafeMutablePointer <Void>) { if context == &myContext { if let newValue = change?[NSKeyValueChangeNewKey] { print("Date changed: (newValue)") } } else { super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context) } }
Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext) override func observeValueForKeyPath(keyPath:String?, ofObject object: AnyObject?, change: [ String : AnyObject ]?, context: UnsafeMutablePointer <Void>) { if context == &myContext { if let newValue = change?[NSKeyValueChangeNewKey] { print("Date changed: (newValue)") } } else { super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context) } } objectToObserve.removeObserver(self, forKeyPath: "myDate", context: &myContext)
Design Patterns in Swift 2.2CocoaConf Austin 2016 SWIFT-NATIVE KVO *MAYBE* IN SWIFT 4 15 
 Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN 16  In Objective-C, we use @selector to wrap the method name when adding it as a target. In Swift 1.x, we just used a String and still had no compiler typo checking. In Swift 2.2, we have #selector (SE-0022) and we FINALLY have compiler type checking. OSS FTW!! ATTACH AN ACTION TO A UI ELEMENT
Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17 
Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") }
Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") } #if swift(>=2.2) myButton.addTarget(self, action: #selector(tappedButton), forControlEvents: .TouchUpInside) #else myButton.addTarget(self, action: "tappedButton", forControlEvents: .TouchUpInside) #endif
Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") } #if swift(>=2.2) myButton.addTarget(self, action: #selector(tappedButton), forControlEvents: .TouchUpInside) #else myButton.addTarget(self, action: "tappedButton", forControlEvents: .TouchUpInside) #endif 1 Legacy Objective-C Only @objc functions can be made #selectors
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN 18  Fairly common in Cocoa, like [UIApplication sharedApplication] In Swift, they’re much simpler to declare (and like ObjC, never dealloc’ed). A static type property is guaranteed to be lazily initialized only once, even when accessed across multiple threads simultaneously. SINGLETONS: GLOBAL SHARED INSTANCE
Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN IN SWIFT 19  class Singleton { static let sharedInstance = Singleton() }
Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN IN SWIFT 19  class Singleton { static let sharedInstance = Singleton() } [] Well, That Was Easy Obj-C is so much more complicated [] Not All Shared Instances Are Singletons e.g. NSFileManager
 Design Patterns in Swift 2.2CocoaConf Austin 2016 “INTROSPECTION PATTERN” 20  Apple’s Docs call this a pattern. It’s pretty much the same functionality as we discussed for Delegation. In my mind, “is this a kind of X class” and “does this implement Y method” are very limited forms of Introspection. DYNAMICALLY EXAMINE TYPES AT RUNTIME
 Design Patterns in Swift 2.2CocoaConf Austin 2016 “INTROSPECTION PATTERN” 20  Apple’s Docs call this a pattern. It’s pretty much the same functionality as we discussed for Delegation. In my mind, “is this a kind of X class” and “does this implement Y method” are very limited forms of Introspection. DYNAMICALLY EXAMINE TYPES AT RUNTIME [] Not Very Useful Way harder in pure Swift than ObjC. Most attempts bridge NSObjects.
 Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” 21  Swift does this at Compile time rather than Runtime (like ObjC). Calling this a “Pattern” seems like a bit of a stretch to me, but Apple does. It is indisputably useful, though. DECIDE WHETHER AN API IS AVAILABLE
 Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” 21  Swift does this at Compile time rather than Runtime (like ObjC). Calling this a “Pattern” seems like a bit of a stretch to me, but Apple does. It is indisputably useful, though. DECIDE WHETHER AN API IS AVAILABLE [] Also for Swift Version #s Starting with Swift 2.2
Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. }
Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  let locationManager = CLLocationManager() if #available(iOS 8.0, OSX 10.10, *) { locationManager.requestWhenInUseAuthorization() } let locationManager = CLLocationManager() guard #available(iOS 8.0, OSX 10.10, *) else { return } locationManager.requestWhenInUseAuthorization() if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. }
Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  let locationManager = CLLocationManager() if #available(iOS 8.0, OSX 10.10, *) { locationManager.requestWhenInUseAuthorization() } let locationManager = CLLocationManager() guard #available(iOS 8.0, OSX 10.10, *) else { return } locationManager.requestWhenInUseAuthorization() if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. } #if swift(>=2.2) let tapped = #selector(tappedButton) #endif
 Design Patterns in Swift 2.2CocoaConf Austin 2016 VALUE TYPES/STRUCTS 23  Swift structs can have methods and implement protocols much like classes, but they’re always passed by value (copied) rather than passed by reference like objects (which makes them generally thread-safe, amongst other things). SWIFT HAS RICH VALUE-TYPES
 Design Patterns in Swift 2.2CocoaConf Austin 2016 UBIQUITOUS IMMUTABILITY 24  Pretty much all Swift variables can be declared immutable (with ‘let’), not just certain types like ObjC. Immutable variables are safer, thread-safe and side-effect free, which is one claim to fame for functional languages. NOT JUST FOR STRING/DICT/ARRAY ANYMORE
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 25  Swift has several mechanisms to keep error checking outside and separate from your business logic. Checks often get moved from runtime to compile time, and syntax allows for checks to be isolated to avoid further complicating already-intricate code. KEEP ERROR CHECKING AWAY FROM YOUR ALGORITHMS
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 1: if let 26  Much safer than finding out the hard way at runtime. Unless you use (!) You don’t use (!), do you? (At least not in shipping apps…) ENFORCES NIL-CHECK AT COMPILE TIME
Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 1: if let 27  if let obj = obj { //business logic about object goes here }
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 2: guard 28  Good for checking at the top of a method Avoids the “if-let pyramid of doom” LIKE if-let, BUT WITH CONTINUING SCOPE
Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 2: guard 29  guard let obj = obj as? NSString where obj.length > 0 else { return } //business logic about object goes here
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 3: defer 30  Make sure something happens as you exit a scope SCHEDULE SOMETHING FOR LATER
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 3: defer 30  Make sure something happens as you exit a scope SCHEDULE SOMETHING FOR LATER [] Dearly Departed @synchronized(dict) { //use dict safely }
Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 3: defer 31  let lock = NSLock() func useLock() { lock.lock() defer { lock.unlock() } //use lock }
 Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS: try? 32  The try syntax gets scattered all over your code. Not exactly as good, but at least better than NSError** (or god forbid C’s return codes and errno). TRY IS A COUNTER-EXAMPLE THOUGH
Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT: try? 33  let url = try fileManager.URLForDirectory(.ApplicationDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false) try fileManager.removeItemAtURL( url.URLByAppendingPathComponent("/path/to/file", isDirectory: true)) if let path = url.URLByAppendingPathComponent("/path/to/file").path { let files = try fileManager.contentsOfDirectoryAtPath(path) //do something with files }
Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT: try? 33  let url = try fileManager.URLForDirectory(.ApplicationDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false) try fileManager.removeItemAtURL( url.URLByAppendingPathComponent("/path/to/file", isDirectory: true)) if let path = url.URLByAppendingPathComponent("/path/to/file").path { let files = try fileManager.contentsOfDirectoryAtPath(path) //do something with files }
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MONADS (A LA HASKELL MAYBE) 34  Very complicated, at least if you believe most people. I remember being amazed - *Really amazed* at WWDC 2014 when I realized Apple stuck a Haskell Maybe Monad into Swift, and used all of 1-character to do it. FUNCTIONAL PROGRAMMING CONCEPT
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD 35 
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36 
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional 
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?  
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ?
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ?
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ? !
Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ? ! [] “!” Considered HARMFUL I mean that in a “GOTO” sense.
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE 37  Without this, the Internet as you know it would never have come to exist, and least not when and how it did. SEMINAL PAPER BEHIND EARLY GOOGLE http://static.googleusercontent.com/media/research.google.com/es/us/archive/mapreduce-osdi04.pdf
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38 
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38          
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38           [] Rule of thumb Same count, Different Type
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP IN SWIFT 39 let names = ["RedStripeOnWhite.jpg","OrangeStripeOnWhite.jpg", "YellowStripeOnWhite.jpg","GreenStripeOnWhite.jpg", "BlackHorizontal.jpg","BlueStripeOnWhite.jpg", “IndigoStripeOnWhite.jpg”,"VioletStripeOnWhite.jpg"] let images = names.map { UIImage(named: $0) }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP IN SWIFT 39 let names = ["RedStripeOnWhite.jpg","OrangeStripeOnWhite.jpg", "YellowStripeOnWhite.jpg","GreenStripeOnWhite.jpg", "BlackHorizontal.jpg","BlueStripeOnWhite.jpg", “IndigoStripeOnWhite.jpg”,"VioletStripeOnWhite.jpg"] let images = names.map { UIImage(named: $0) } 1 Real WorlD: JSON I use this a lot to map JSON Dict to Object/Struct, but this is more visual
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40 
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40         
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40          [] Rule of thumb Same Type, Lower Count
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER IN SWIFT 41  let colors = images.filter { !mono($0) }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER IN SWIFT 41  let colors = images.filter { !mono($0) } 1 Real WorlD: JSON I use this a lot to throw out JSON Dicts I don’t need
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42 
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42      
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42       [] Rule of thumb Different Type, Count == 1
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 43  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 43  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 44  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 44  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 45  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 45  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 46  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 46  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 47  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 47  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 48  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 48  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 49  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 49  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE - WAIT, WAIT, WAIT!!! 50  I have yet to see a case where map/reduce worked consistently faster on iOS than the equivalent for..in loop, and often it can be quite a bit slower. BUT - learn it anyway. ABOUT SWIFT’S MAPREDUCE PERFORMANCE…
 Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE - SO WHAT’S THE POINT? 51  …or threads. Or at least, that was the design intent. I still use it (although I don’t have to), because I’m used to it from other languages (and I use it with dispatch_groups, despite the fact they don’t fit on slides). But Soon (SWIFT 4?? - see earlier email), we’ll have a Swift release that focuses on asynchronous functionality. And THEN, it will really, really matter. MAPREDUCE SPLITS WORK BETWEEN MACHINES
 Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL DEFAULT IMPLEMENTATIONS 52  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD
 Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL EXTENSIONS (W/IMPLEMENTATIONS) 53  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD
 Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL EXTENSIONS (W/IMPLEMENTATIONS) 53  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD 1 Examples are Contrived And they take a while to set up, and I’m expecting this is already going long 2 Big Topic There’s a whole (VERY GOOD) WWDC talk on just this.
Speaking to you all is always a pleasure. Thank You
Speaking to you all is always a pleasure. Thank You

More Related Content

What's hot (19)

PDF
T3DD13 - Automated deployment for TYPO3 CMS (Workshop)
Tobias Liebig
 
PDF
Openshift: Deployments for the rest of us
Anurag Patel
 
PPT
sbt 0.10 for beginners?
k4200
 
PPT
Lifthub (rpscala #31)
k4200
 
PDF
Bgoug 2019.11 test your pl sql - not your patience
Jacek Gebal
 
PDF
Golang workshop
Victor S. Recio
 
PPT
Griffon: Swing just got fun again
James Williams
 
PDF
Let the contribution begin (EST futures)
SeongJae Park
 
PPTX
Dead-Simple Async Control Flow with Coroutines
Travis Kaufman
 
PDF
5 Simple Tips for Troubleshooting Your Kubernetes Pods
DevOps.com
 
PPTX
Gitflow - Una metología para manejo de Branches
Javier Alvarez
 
PDF
Node.js + influx + grafana
Lucas Inocente
 
PDF
19 GitFlow #burningkeyboards
Denis Ristic
 
PDF
Let the contribution begin
SeongJae Park
 
PDF
Frida Android run time hooking - Bhargav Gajera & Vitthal Shinde
NSConclave
 
PPTX
Git hooks
BinBin He
 
PDF
Killer R10K Workflow - PuppetConf 2014
Puppet
 
PPTX
Bamboo Hands on training 2016
Takahiro Yamaki
 
PDF
Enjoy privacy on Gitlab
Maxis Kao
 
T3DD13 - Automated deployment for TYPO3 CMS (Workshop)
Tobias Liebig
 
Openshift: Deployments for the rest of us
Anurag Patel
 
sbt 0.10 for beginners?
k4200
 
Lifthub (rpscala #31)
k4200
 
Bgoug 2019.11 test your pl sql - not your patience
Jacek Gebal
 
Golang workshop
Victor S. Recio
 
Griffon: Swing just got fun again
James Williams
 
Let the contribution begin (EST futures)
SeongJae Park
 
Dead-Simple Async Control Flow with Coroutines
Travis Kaufman
 
5 Simple Tips for Troubleshooting Your Kubernetes Pods
DevOps.com
 
Gitflow - Una metología para manejo de Branches
Javier Alvarez
 
Node.js + influx + grafana
Lucas Inocente
 
19 GitFlow #burningkeyboards
Denis Ristic
 
Let the contribution begin
SeongJae Park
 
Frida Android run time hooking - Bhargav Gajera & Vitthal Shinde
NSConclave
 
Git hooks
BinBin He
 
Killer R10K Workflow - PuppetConf 2014
Puppet
 
Bamboo Hands on training 2016
Takahiro Yamaki
 
Enjoy privacy on Gitlab
Maxis Kao
 

Similar to Swift 2.2 Design Patterns CocoaConf Austin 2016 (20)

PDF
Cocoa Heads Tricity - Design Patterns
Maciej Burda
 
PDF
Design Patterns in iOS
Yi-Shou Chen
 
PPTX
Design patterns
Jeff Potter
 
PDF
Design Patterns in Swift ch0 Introduction
Chihyang Li
 
PPTX
Fundamental Design Patterns.pptx
JUNSHIN8
 
PDF
9 Best Design Patterns in iOS to Develop Powerful iPhone Apps.pdf
Concetto Labs
 
PPTX
9 Best Design Patterns in iOS to Develop Powerful iPhone Apps.pptx
Concetto Labs
 
PDF
Swift 2.0: Apple’s Advanced Programming Platform for Developers
Azilen Technologies Pvt. Ltd.
 
PDF
Design Patterns in Cocoa Touch
Eliah Nikans
 
PDF
Tips and Tricks for Swift & Dot Swift 2016
Adam Gask
 
PDF
(E book pdf) thinking in patterns with java
Raffaella D'angelo
 
PDF
Programming iOS 5 2nd Edition Matt Neuburg
saertahai
 
PPT
Swift: Apple's New Programming Language for iOS and OS X
Sasha Goldshtein
 
ODP
Design Patterns Part1
Tom Chen
 
PDF
Programming Ios 5 2nd Edition 2nd Early Release Draft Matt Neuburg
lindzpeccoo
 
PDF
Generation of Automatic Code using Design Patterns
IRJET Journal
 
PDF
Programming iOS 4 Fundamentals of iPhone iPad and iPod Touch Development 1st ...
assangkaoua
 
KEY
Design Patterns Course
Ahmed Soliman
 
PPTX
Final sdp ppt
nancy_17
 
PDF
Design patterns for fun & profit - CoderCruise 2018
David Litvak Bruno
 
Cocoa Heads Tricity - Design Patterns
Maciej Burda
 
Design Patterns in iOS
Yi-Shou Chen
 
Design patterns
Jeff Potter
 
Design Patterns in Swift ch0 Introduction
Chihyang Li
 
Fundamental Design Patterns.pptx
JUNSHIN8
 
9 Best Design Patterns in iOS to Develop Powerful iPhone Apps.pdf
Concetto Labs
 
9 Best Design Patterns in iOS to Develop Powerful iPhone Apps.pptx
Concetto Labs
 
Swift 2.0: Apple’s Advanced Programming Platform for Developers
Azilen Technologies Pvt. Ltd.
 
Design Patterns in Cocoa Touch
Eliah Nikans
 
Tips and Tricks for Swift & Dot Swift 2016
Adam Gask
 
(E book pdf) thinking in patterns with java
Raffaella D'angelo
 
Programming iOS 5 2nd Edition Matt Neuburg
saertahai
 
Swift: Apple's New Programming Language for iOS and OS X
Sasha Goldshtein
 
Design Patterns Part1
Tom Chen
 
Programming Ios 5 2nd Edition 2nd Early Release Draft Matt Neuburg
lindzpeccoo
 
Generation of Automatic Code using Design Patterns
IRJET Journal
 
Programming iOS 4 Fundamentals of iPhone iPad and iPod Touch Development 1st ...
assangkaoua
 
Design Patterns Course
Ahmed Soliman
 
Final sdp ppt
nancy_17
 
Design patterns for fun & profit - CoderCruise 2018
David Litvak Bruno
 
Ad

More from Carl Brown (20)

PDF
GDPR, User Data, Privacy, and Your Apps
Carl Brown
 
PDF
New in iOS 11.3b4 and Xcode 9.3b4
Carl Brown
 
PDF
Managing Memory in Swift (Yes, that's a thing)
Carl Brown
 
PDF
Better Swift from the Foundation up #tryswiftnyc17 09-06
Carl Brown
 
PDF
Generics, the Swift ABI and you
Carl Brown
 
PDF
Swift GUI Development without Xcode
Carl Brown
 
PDF
what's new in iOS10 2016-06-23
Carl Brown
 
PDF
Parse migration CocoaCoders April 28th, 2016
Carl Brown
 
PDF
Advanced, Composable Collection Views, From CocoaCoders meetup Austin Feb 12,...
Carl Brown
 
PDF
Gcd cc-150205
Carl Brown
 
PDF
Cocoa coders 141113-watch
Carl Brown
 
PDF
iOS8 and the new App Store
Carl Brown
 
PDF
Dark Art of Software Estimation 360iDev2014
Carl Brown
 
PDF
Intro to cloud kit Cocoader.org 24 July 2014
Carl Brown
 
PDF
Welcome to Swift (CocoaCoder 6/12/14)
Carl Brown
 
PDF
Writing Apps that Can See: Getting Data from CoreImage to Computer Vision - ...
Carl Brown
 
PPT
Introduction to Git Commands and Concepts
Carl Brown
 
PDF
REST/JSON/CoreData Example Code - A Tour
Carl Brown
 
KEY
360iDev iOS AntiPatterns
Carl Brown
 
KEY
Chipmunk physics presentation
Carl Brown
 
GDPR, User Data, Privacy, and Your Apps
Carl Brown
 
New in iOS 11.3b4 and Xcode 9.3b4
Carl Brown
 
Managing Memory in Swift (Yes, that's a thing)
Carl Brown
 
Better Swift from the Foundation up #tryswiftnyc17 09-06
Carl Brown
 
Generics, the Swift ABI and you
Carl Brown
 
Swift GUI Development without Xcode
Carl Brown
 
what's new in iOS10 2016-06-23
Carl Brown
 
Parse migration CocoaCoders April 28th, 2016
Carl Brown
 
Advanced, Composable Collection Views, From CocoaCoders meetup Austin Feb 12,...
Carl Brown
 
Gcd cc-150205
Carl Brown
 
Cocoa coders 141113-watch
Carl Brown
 
iOS8 and the new App Store
Carl Brown
 
Dark Art of Software Estimation 360iDev2014
Carl Brown
 
Intro to cloud kit Cocoader.org 24 July 2014
Carl Brown
 
Welcome to Swift (CocoaCoder 6/12/14)
Carl Brown
 
Writing Apps that Can See: Getting Data from CoreImage to Computer Vision - ...
Carl Brown
 
Introduction to Git Commands and Concepts
Carl Brown
 
REST/JSON/CoreData Example Code - A Tour
Carl Brown
 
360iDev iOS AntiPatterns
Carl Brown
 
Chipmunk physics presentation
Carl Brown
 
Ad

Recently uploaded (20)

PDF
POV_ Why Enterprises Need to Find Value in ZERO.pdf
darshakparmar
 
PDF
Using FME to Develop Self-Service CAD Applications for a Major UK Police Force
Safe Software
 
PDF
Exolore The Essential AI Tools in 2025.pdf
Srinivasan M
 
PPTX
Future Tech Innovations 2025 – A TechLists Insight
TechLists
 
PPTX
From Sci-Fi to Reality: Exploring AI Evolution
Svetlana Meissner
 
PPTX
AUTOMATION AND ROBOTICS IN PHARMA INDUSTRY.pptx
sameeraaabegumm
 
PDF
CIFDAQ Market Wrap for the week of 4th July 2025
CIFDAQ
 
PPTX
WooCommerce Workshop: Bring Your Laptop
Laura Hartwig
 
PDF
"Beyond English: Navigating the Challenges of Building a Ukrainian-language R...
Fwdays
 
PDF
Bitcoin for Millennials podcast with Bram, Power Laws of Bitcoin
Stephen Perrenod
 
PDF
Advancing WebDriver BiDi support in WebKit
Igalia
 
PDF
DevBcn - Building 10x Organizations Using Modern Productivity Metrics
Justin Reock
 
PDF
Newgen Beyond Frankenstein_Build vs Buy_Digital_version.pdf
darshakparmar
 
PDF
The Rise of AI and IoT in Mobile App Tech.pdf
IMG Global Infotech
 
PPTX
"Autonomy of LLM Agents: Current State and Future Prospects", Oles` Petriv
Fwdays
 
PDF
Empower Inclusion Through Accessible Java Applications
Ana-Maria Mihalceanu
 
PDF
Staying Human in a Machine- Accelerated World
Catalin Jora
 
PDF
Smart Trailers 2025 Update with History and Overview
Paul Menig
 
PPTX
Q2 FY26 Tableau User Group Leader Quarterly Call
lward7
 
PDF
IoT-Powered Industrial Transformation – Smart Manufacturing to Connected Heal...
Rejig Digital
 
POV_ Why Enterprises Need to Find Value in ZERO.pdf
darshakparmar
 
Using FME to Develop Self-Service CAD Applications for a Major UK Police Force
Safe Software
 
Exolore The Essential AI Tools in 2025.pdf
Srinivasan M
 
Future Tech Innovations 2025 – A TechLists Insight
TechLists
 
From Sci-Fi to Reality: Exploring AI Evolution
Svetlana Meissner
 
AUTOMATION AND ROBOTICS IN PHARMA INDUSTRY.pptx
sameeraaabegumm
 
CIFDAQ Market Wrap for the week of 4th July 2025
CIFDAQ
 
WooCommerce Workshop: Bring Your Laptop
Laura Hartwig
 
"Beyond English: Navigating the Challenges of Building a Ukrainian-language R...
Fwdays
 
Bitcoin for Millennials podcast with Bram, Power Laws of Bitcoin
Stephen Perrenod
 
Advancing WebDriver BiDi support in WebKit
Igalia
 
DevBcn - Building 10x Organizations Using Modern Productivity Metrics
Justin Reock
 
Newgen Beyond Frankenstein_Build vs Buy_Digital_version.pdf
darshakparmar
 
The Rise of AI and IoT in Mobile App Tech.pdf
IMG Global Infotech
 
"Autonomy of LLM Agents: Current State and Future Prospects", Oles` Petriv
Fwdays
 
Empower Inclusion Through Accessible Java Applications
Ana-Maria Mihalceanu
 
Staying Human in a Machine- Accelerated World
Catalin Jora
 
Smart Trailers 2025 Update with History and Overview
Paul Menig
 
Q2 FY26 Tableau User Group Leader Quarterly Call
lward7
 
IoT-Powered Industrial Transformation – Smart Manufacturing to Connected Heal...
Rejig Digital
 

Swift 2.2 Design Patterns CocoaConf Austin 2016

  • 1. Swift 2.2 Design Patterns COCOACONF AUSTIN APRIL 2016 Skyline Credit: User:Argash [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons @CarlBrwn
  • 2. Swift 2.2 Design Patterns COCOACONF AUSTIN APRIL 2016 Skyline Credit: User:Argash [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons @CarlBrwn
  • 3. [:]? So, who is this idiot, anyway? INTRODUCTION @CarlBrwn
  • 5. These mean a lot of different things to different people. Hopefully they’re of some use to you. WIDELY RECOGNIZED, BUT NOT UNDISPUTED
  • 6. These mean a lot of different things to different people. Hopefully they’re of some use to you. WIDELY RECOGNIZED, BUT NOT UNDISPUTED [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
  • 7. So, Let’s talk about Swift (2.2 Version) PATTERNS ARE LANGUAGE SPECIFIC [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
  • 8. So, Let’s talk about Swift (2.2 Version) & Cocoa PATTERNS ARE LANGUAGE (& FRAMEWORK) SPECIFIC [:]? Critical Concept in Software Engineering? Some think so, others disagree. [:]? Simple Enumeration of Weaknesses in C++ See http://www.norvig.com/design- patterns/ [:]? Just Shared Vocabulary?
  • 9. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8 
  • 10. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift
  • 11. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift
  • 12. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift
  • 13. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift Patterns from Other Languages
  • 14. Design Patterns in Swift 2.2CocoaConf Austin 2016 PATTERN SOURCES FOR TODAY 8  Classic Cocoa Design Patterns as implemented in Swift Some Gang of Four Patterns that lend themselves to Swift Patterns Apple Documents for Swift Patterns from Other Languages Interesting/Potential Swift-specific Patterns
  • 15.  Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN 9  Cocoa is said to favor “Composition over Inheritance.” Delegation is one of the hallmarks of that strategy. UITableViewDataSource and UITableViewDelegate are examples. CLASSIC COCOA PATTERN
  • 16.  Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN 9  Cocoa is said to favor “Composition over Inheritance.” Delegation is one of the hallmarks of that strategy. UITableViewDataSource and UITableViewDelegate are examples. CLASSIC COCOA PATTERN [:]? Eases Construction This is a big reason why we don’t have to use the “Factory Pattern” in Cocoa/ Swift
  • 17. Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN IN SWIFT 10  var myDS : UITableViewDataSource? let myTVC = UITableViewController() let myTV = myTVC.tableView let num = myDS?.tableView(myTV, numberOfRowsInSection: 0) let firstHeader = myDS?.tableView?(myTV, titleForHeaderInSection: 0)
  • 18. Design Patterns in Swift 2.2CocoaConf Austin 2016 DELEGATE PATTERN IN SWIFT 10  var myDS : UITableViewDataSource? let myTVC = UITableViewController() let myTV = myTVC.tableView let num = myDS?.tableView(myTV, numberOfRowsInSection: 0) let firstHeader = myDS?.tableView?(myTV, titleForHeaderInSection: 0) 1 Test Delegate Optional The delegate itself must not be nil (check with ? and don’t (EVER) use !) 2 Test Method Exists Put ? after method call to test for @optional implementation
  • 19.  Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN 11  In Cocoa, methods that produce errors take an NSError pointer parameter last parameter. In Swift 2, this is converted to a thrown ErrorType NEW IN SWIFT 2 - HOOKS INTO COCOA’S (NSError**)
  • 20.  Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN 11  In Cocoa, methods that produce errors take an NSError pointer parameter last parameter. In Swift 2, this is converted to a thrown ErrorType NEW IN SWIFT 2 - HOOKS INTO COCOA’S (NSError**) [] Not JAva’s Throw try on each line that might throw catch for blocks
  • 21. Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN IN SWIFT 12  - (BOOL)removeItemAtURL:(NSURL *)URL error:(NSError **)error { NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *URL = [NSURL fileURLWithPath:@"/path/to/file"]; NSError *error = nil; BOOL success = [fileManager removeItemAtURL:URL error:&error]; if (!success) { NSLog(@"Error: %@", error.domain); } }
  • 22. Design Patterns in Swift 2.2CocoaConf Austin 2016 ERROR HANDLING PATTERN IN SWIFT 12  func removeItemAtURL(URL: NSURL) throws { let fileManager = NSFileManager.defaultManager() let URL = NSURL.fileURLWithPath("/path/to/file") do { try fileManager.removeItemAtURL(URL) } catch let error as NSError { print("Error: (error.domain)") } } - (BOOL)removeItemAtURL:(NSURL *)URL error:(NSError **)error { NSFileManager *fileManager = [NSFileManager defaultManager]; NSURL *URL = [NSURL fileURLWithPath:@"/path/to/file"]; NSError *error = nil; BOOL success = [fileManager removeItemAtURL:URL error:&error]; if (!success) { NSLog(@"Error: %@", error.domain); } }
  • 23.  Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN 13  Key-Value Observing lets you observe any well-behaved Cocoa property (getter/setter). It works in Swift *As Long As* the target isKindOf: NSObject KVO IN SWIFT
  • 24. Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14 
  • 25. Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext)
  • 26. Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext) override func observeValueForKeyPath(keyPath:String?, ofObject object: AnyObject?, change: [ String : AnyObject ]?, context: UnsafeMutablePointer <Void>) { if context == &myContext { if let newValue = change?[NSKeyValueChangeNewKey] { print("Date changed: (newValue)") } } else { super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context) } }
  • 27. Design Patterns in Swift 2.2CocoaConf Austin 2016 OBSERVER PATTERN IN SWIFT 14  objectToObserve.addObserver(self, forKeyPath: "myDate", options: .New, context: &myContext) override func observeValueForKeyPath(keyPath:String?, ofObject object: AnyObject?, change: [ String : AnyObject ]?, context: UnsafeMutablePointer <Void>) { if context == &myContext { if let newValue = change?[NSKeyValueChangeNewKey] { print("Date changed: (newValue)") } } else { super.observeValueForKeyPath(keyPath, ofObject: object, change: change, context: context) } } objectToObserve.removeObserver(self, forKeyPath: "myDate", context: &myContext)
  • 28. Design Patterns in Swift 2.2CocoaConf Austin 2016 SWIFT-NATIVE KVO *MAYBE* IN SWIFT 4 15 
  • 29.  Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN 16  In Objective-C, we use @selector to wrap the method name when adding it as a target. In Swift 1.x, we just used a String and still had no compiler typo checking. In Swift 2.2, we have #selector (SE-0022) and we FINALLY have compiler type checking. OSS FTW!! ATTACH AN ACTION TO A UI ELEMENT
  • 30. Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17 
  • 31. Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") }
  • 32. Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") } #if swift(>=2.2) myButton.addTarget(self, action: #selector(tappedButton), forControlEvents: .TouchUpInside) #else myButton.addTarget(self, action: "tappedButton", forControlEvents: .TouchUpInside) #endif
  • 33. Design Patterns in Swift 2.2CocoaConf Austin 2016 TARGET-ACTION PATTERN IN SWIFT 17  @objc func tappedButton(sender:UIButton!) { print("tapped button") } #if swift(>=2.2) myButton.addTarget(self, action: #selector(tappedButton), forControlEvents: .TouchUpInside) #else myButton.addTarget(self, action: "tappedButton", forControlEvents: .TouchUpInside) #endif 1 Legacy Objective-C Only @objc functions can be made #selectors
  • 34.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN 18  Fairly common in Cocoa, like [UIApplication sharedApplication] In Swift, they’re much simpler to declare (and like ObjC, never dealloc’ed). A static type property is guaranteed to be lazily initialized only once, even when accessed across multiple threads simultaneously. SINGLETONS: GLOBAL SHARED INSTANCE
  • 35. Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN IN SWIFT 19  class Singleton { static let sharedInstance = Singleton() }
  • 36. Design Patterns in Swift 2.2CocoaConf Austin 2016 SINGLETON PATTERN IN SWIFT 19  class Singleton { static let sharedInstance = Singleton() } [] Well, That Was Easy Obj-C is so much more complicated [] Not All Shared Instances Are Singletons e.g. NSFileManager
  • 37.  Design Patterns in Swift 2.2CocoaConf Austin 2016 “INTROSPECTION PATTERN” 20  Apple’s Docs call this a pattern. It’s pretty much the same functionality as we discussed for Delegation. In my mind, “is this a kind of X class” and “does this implement Y method” are very limited forms of Introspection. DYNAMICALLY EXAMINE TYPES AT RUNTIME
  • 38.  Design Patterns in Swift 2.2CocoaConf Austin 2016 “INTROSPECTION PATTERN” 20  Apple’s Docs call this a pattern. It’s pretty much the same functionality as we discussed for Delegation. In my mind, “is this a kind of X class” and “does this implement Y method” are very limited forms of Introspection. DYNAMICALLY EXAMINE TYPES AT RUNTIME [] Not Very Useful Way harder in pure Swift than ObjC. Most attempts bridge NSObjects.
  • 39.  Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” 21  Swift does this at Compile time rather than Runtime (like ObjC). Calling this a “Pattern” seems like a bit of a stretch to me, but Apple does. It is indisputably useful, though. DECIDE WHETHER AN API IS AVAILABLE
  • 40.  Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” 21  Swift does this at Compile time rather than Runtime (like ObjC). Calling this a “Pattern” seems like a bit of a stretch to me, but Apple does. It is indisputably useful, though. DECIDE WHETHER AN API IS AVAILABLE [] Also for Swift Version #s Starting with Swift 2.2
  • 41. Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. }
  • 42. Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  let locationManager = CLLocationManager() if #available(iOS 8.0, OSX 10.10, *) { locationManager.requestWhenInUseAuthorization() } let locationManager = CLLocationManager() guard #available(iOS 8.0, OSX 10.10, *) else { return } locationManager.requestWhenInUseAuthorization() if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. }
  • 43. Design Patterns in Swift 2.2CocoaConf Austin 2016 API AVAILABILITY CHECKING “PATTERN” IN SWIFT 22  let locationManager = CLLocationManager() if #available(iOS 8.0, OSX 10.10, *) { locationManager.requestWhenInUseAuthorization() } let locationManager = CLLocationManager() guard #available(iOS 8.0, OSX 10.10, *) else { return } locationManager.requestWhenInUseAuthorization() if ([CLLocationManager instancesRespondToSelector:@selector(requestWhenInUseAuthorization)]) { // Method is available for use. } else { // Method is not available. } #if swift(>=2.2) let tapped = #selector(tappedButton) #endif
  • 44.  Design Patterns in Swift 2.2CocoaConf Austin 2016 VALUE TYPES/STRUCTS 23  Swift structs can have methods and implement protocols much like classes, but they’re always passed by value (copied) rather than passed by reference like objects (which makes them generally thread-safe, amongst other things). SWIFT HAS RICH VALUE-TYPES
  • 45.  Design Patterns in Swift 2.2CocoaConf Austin 2016 UBIQUITOUS IMMUTABILITY 24  Pretty much all Swift variables can be declared immutable (with ‘let’), not just certain types like ObjC. Immutable variables are safer, thread-safe and side-effect free, which is one claim to fame for functional languages. NOT JUST FOR STRING/DICT/ARRAY ANYMORE
  • 46.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 25  Swift has several mechanisms to keep error checking outside and separate from your business logic. Checks often get moved from runtime to compile time, and syntax allows for checks to be isolated to avoid further complicating already-intricate code. KEEP ERROR CHECKING AWAY FROM YOUR ALGORITHMS
  • 47.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 1: if let 26  Much safer than finding out the hard way at runtime. Unless you use (!) You don’t use (!), do you? (At least not in shipping apps…) ENFORCES NIL-CHECK AT COMPILE TIME
  • 48. Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 1: if let 27  if let obj = obj { //business logic about object goes here }
  • 49.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 2: guard 28  Good for checking at the top of a method Avoids the “if-let pyramid of doom” LIKE if-let, BUT WITH CONTINUING SCOPE
  • 50. Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 2: guard 29  guard let obj = obj as? NSString where obj.length > 0 else { return } //business logic about object goes here
  • 51.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 3: defer 30  Make sure something happens as you exit a scope SCHEDULE SOMETHING FOR LATER
  • 52.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS 3: defer 30  Make sure something happens as you exit a scope SCHEDULE SOMETHING FOR LATER [] Dearly Departed @synchronized(dict) { //use dict safely }
  • 53. Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT 3: defer 31  let lock = NSLock() func useLock() { lock.lock() defer { lock.unlock() } //use lock }
  • 54.  Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS: try? 32  The try syntax gets scattered all over your code. Not exactly as good, but at least better than NSError** (or god forbid C’s return codes and errno). TRY IS A COUNTER-EXAMPLE THOUGH
  • 55. Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT: try? 33  let url = try fileManager.URLForDirectory(.ApplicationDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false) try fileManager.removeItemAtURL( url.URLByAppendingPathComponent("/path/to/file", isDirectory: true)) if let path = url.URLByAppendingPathComponent("/path/to/file").path { let files = try fileManager.contentsOfDirectoryAtPath(path) //do something with files }
  • 56. Design Patterns in Swift 2.2CocoaConf Austin 2016 SEPARATION OF ERRORS IN SWIFT: try? 33  let url = try fileManager.URLForDirectory(.ApplicationDirectory, inDomain: .UserDomainMask, appropriateForURL: nil, create: false) try fileManager.removeItemAtURL( url.URLByAppendingPathComponent("/path/to/file", isDirectory: true)) if let path = url.URLByAppendingPathComponent("/path/to/file").path { let files = try fileManager.contentsOfDirectoryAtPath(path) //do something with files }
  • 57.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MONADS (A LA HASKELL MAYBE) 34  Very complicated, at least if you believe most people. I remember being amazed - *Really amazed* at WWDC 2014 when I realized Apple stuck a Haskell Maybe Monad into Swift, and used all of 1-character to do it. FUNCTIONAL PROGRAMMING CONCEPT
  • 58. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD 35 
  • 59. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36 
  • 60. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional 
  • 61. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?  
  • 62. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ?
  • 63. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ?
  • 64. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ? !
  • 65. Design Patterns in Swift 2.2CocoaConf Austin 2016 ”MAYBE” MONAD SWIFT OPTIONAL 36  Optional  ! ?   ? ! [] “!” Considered HARMFUL I mean that in a “GOTO” sense.
  • 66.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE 37  Without this, the Internet as you know it would never have come to exist, and least not when and how it did. SEMINAL PAPER BEHIND EARLY GOOGLE http://static.googleusercontent.com/media/research.google.com/es/us/archive/mapreduce-osdi04.pdf
  • 67. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38 
  • 68.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38          
  • 69.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP 38           [] Rule of thumb Same count, Different Type
  • 70. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP IN SWIFT 39 let names = ["RedStripeOnWhite.jpg","OrangeStripeOnWhite.jpg", "YellowStripeOnWhite.jpg","GreenStripeOnWhite.jpg", "BlackHorizontal.jpg","BlueStripeOnWhite.jpg", “IndigoStripeOnWhite.jpg”,"VioletStripeOnWhite.jpg"] let images = names.map { UIImage(named: $0) }
  • 71. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — MAP IN SWIFT 39 let names = ["RedStripeOnWhite.jpg","OrangeStripeOnWhite.jpg", "YellowStripeOnWhite.jpg","GreenStripeOnWhite.jpg", "BlackHorizontal.jpg","BlueStripeOnWhite.jpg", “IndigoStripeOnWhite.jpg”,"VioletStripeOnWhite.jpg"] let images = names.map { UIImage(named: $0) } 1 Real WorlD: JSON I use this a lot to map JSON Dict to Object/Struct, but this is more visual
  • 72. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40 
  • 73. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40         
  • 74. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER 40          [] Rule of thumb Same Type, Lower Count
  • 75. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER IN SWIFT 41  let colors = images.filter { !mono($0) }
  • 76. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — FILTER IN SWIFT 41  let colors = images.filter { !mono($0) } 1 Real WorlD: JSON I use this a lot to throw out JSON Dicts I don’t need
  • 77. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42 
  • 78.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42      
  • 79.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 42       [] Rule of thumb Different Type, Count == 1
  • 80. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 43  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 81. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 43  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 82. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 44  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 83. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 44  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 84. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 45  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 85. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 45  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 86. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 46  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 87. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 46  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 88. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 47  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 89. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 47  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 90. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 48  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 91. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 48  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 92. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 49  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 93. Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE — REDUCE 49  let rainbowImage = ciImages.reduce(CIImage()) { (s, img) -> CIImage? in let f = CIFilter(name: "CISourceOverCompositing") f?.setValue(s, forKey: kCIInputBackgroundImageKey) f?.setValue(img, forKey:kCIInputImageKey) return f?.outputImage }
  • 94.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE - WAIT, WAIT, WAIT!!! 50  I have yet to see a case where map/reduce worked consistently faster on iOS than the equivalent for..in loop, and often it can be quite a bit slower. BUT - learn it anyway. ABOUT SWIFT’S MAPREDUCE PERFORMANCE…
  • 95.  Design Patterns in Swift 2.2CocoaConf Austin 2016 MAPREDUCE - SO WHAT’S THE POINT? 51  …or threads. Or at least, that was the design intent. I still use it (although I don’t have to), because I’m used to it from other languages (and I use it with dispatch_groups, despite the fact they don’t fit on slides). But Soon (SWIFT 4?? - see earlier email), we’ll have a Swift release that focuses on asynchronous functionality. And THEN, it will really, really matter. MAPREDUCE SPLITS WORK BETWEEN MACHINES
  • 96.  Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL DEFAULT IMPLEMENTATIONS 52  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD
  • 97.  Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL EXTENSIONS (W/IMPLEMENTATIONS) 53  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD
  • 98.  Design Patterns in Swift 2.2CocoaConf Austin 2016 PROTOCOL EXTENSIONS (W/IMPLEMENTATIONS) 53  Protocol Implementations allow for much more useful protocols, and for much more flexible implementations. WHOLE NEW WORLD 1 Examples are Contrived And they take a while to set up, and I’m expecting this is already going long 2 Big Topic There’s a whole (VERY GOOD) WWDC talk on just this.
  • 99. Speaking to you all is always a pleasure. Thank You
  • 100. Speaking to you all is always a pleasure. Thank You