A Swift Approach (Warsaw 2014)

Transcript

1. A SWIFT APPROACH KYLEFULLER
2. KYLEFULLER
5. NEW CONCEPTS
6. RUNTIME
7. @objc / NSObject
8. NSKeyValueObserving
9. RUNTIME
10. WWDC 2015
11. OPTIONALS?
12. func compute() -> Bool?
13. true false neither
14. LACK OF A VALUE
15. NOT AN EMPTY VALUE
16. CAN'T WE DO THIS IN OBJECTIVE-C?
17. nil Nil NULL CGRectNull -1 0 NSNotFound NSNull ...
18. EXPRESS YOU DON'T ACCEPT NIL
19. EXPRESS YOU WILL NOT RETURN NIL
20. /// You **MUST** pass in a URL - (instancetype)initWithURL:(NSURL *)URL { NSParameterAssert(URL != nil); }
21. - (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *)path { return nil; }
23. RUNTIME ERROR
24. RUNTIME ERROR
25. COMPILE ERROR
27. TUPLES
28. func get(username:String) -> (Person?, NSError?)
29. let person, error = get("Kyle")
30. OBJECTIVE-C
31. NSError *error; Person *person = [Person getPerson:@"Kyle" error:&error];
32. NAMED TUPLES
33. func get(username:String) -> (person:Person?, error:NSError?)
34. let result = get("Kyle") result.person result.error
35. - (NSArray *)getPerson:(NSString *)username; - (NSDictionary *)getPerson:(NSString *)username;
36. NSDictionary *components = [Person getPerson:@"kyle"]; Person *person = components["person"]; NSError *error = components["error"];
37. TYPE SAFETY?
38. FRAGILE
39. ENUMERATIONS
40. enum Result { case Success(String) case Error(Error) }
41. switch result { case .Error(let error): println("There was an error (\(error)).") case .Success(let string): println("\(string)") }
42. CLOSURES
43. EVERYTHING IS A CLOSURE
44. class TestObject { func testA() -> () { println("first test") } var testB:(() -> ()) = { println("second test") } }
45. let testing = TestObject() testing.testA() testing.testB()
46. testing.testB = testing.testA
47. testing.testB() // Actually calls testA
48. CONSISTENCY
49. FUNCTIONAL
51. let string = "Hello World" let matches:[NSTextCheckingResult] = /* regex for words in string */ matches.map { string.substringWithRange($0.range) }
52. let string = "Hello World" let matches:[NSTextCheckingResult] = /* regex for words in string */ var strings = [String]() for match in matches { let catch = string.substringWithRange(match.range) strings.append(catch) }
53. func reduce(initial, combine) -> result
54. combine : ((previous, current) -> (result))
55. let items = [["a", "b"], ["c", "d"], ["e"]] items.reduce([]) { initial, expressions -> [String] in initial + expressions } => ["a", "b", "c", "d", "e"]
56. let items = [["a", "b"], ["c", "d"], ["e"]] items.reduce([], +) => ["a", "b", "c", "d", "e"]
57. func +<T>(lhs:[T], rhs:[T]) -> [T]
58. items.sort { $0 > $1 }
59. items.sort(>)
60. items.filter { $0.hasPermission }
61. func isAdmin(user:User) -> Bool { return user.username == "Kyle" } users.filter(isAdmin)
62. GENERICS
63. Array<String>
64. Dictionary<String, Int>
65. func max<T : Comparable>(a:T, b:T) -> T { return a > b ? a : b }
66. max(anInteger, anotherInteger) max(aFloat, anotherFloat) max(aString, anotherString)
67. PATTERN MATCHING
68. let point = (1, 2) switch point { case (0, 0): println("(0, 0) is at the origin.") case (-2...2, -2...2): println("(\(point.0), \(point.1)) is near the origin.") default: println("The point is at (\(point.0), \(point.1)).") } // prints "(1, 2) is near the origin."
69. @auto_closure
70. delay(5, println("Hello World"))
71. func delay(time:UInt32, block:@auto_closure) { sleep(time) block() }
72. BUILDING ASSERT() IN SWIFT
73. assert(someExpensiveComputation() != 42)
74. func assert(predicate : () -> Bool) { #if !NDEBUG if !predicate() { abort() } #endif }
75. PLAYGROUNDS
76. PLAYGROUNDS
77. SWIFT
78. SAFER
79. CONVENTIONS
80. CONVENTIONS
81. LANGUAGE CONSTRAINTS
82. BETTER CODE
83. BETTER DEVELOPERS
84. LESS BUGS
85. WE'RE ALL BEGINNERS
86. PERFECTING
87. BREAKING CHANGES
88. - Xcode 6.1 + Xcode 6.1.1
89. FOR GOOD, NOT EVIL
90. !
91. FILE RADARS
92. FUTURE
93. COMMON DESIGN PATTERNS
94. KYLEFULLER