SE를 통해 본 스위프트 3.0의 변화

1. letswift(16)
스위프트 3.0
Swift는 어디로 가는가
OSXDEV.org박세현

2. Agenda
Swift 역사
Swift 3.0 훑어보기
Swift Evolution & 구현

3. Swift History
2010년 7월 Swift 개발 시작
2014년 6월 2일 WWDC 앱 Swift로 작성된 공개 앱.
2014년 9월 9일 Swift 1.0 마일스톤
2014년 10월 22일 Swift 1.1
2015년 4월 8일 Swift 1.2
2015년 WWDC Swift 2.0 발표
2015년 12월 3일 Swift 오픈소스 발표, 3.0 로드맵 발표

4. Swift 1.2
성능향상
if-let 개선(바인딩)
as 키워드로 업캐스팅/다운캐스팅
Set 추가
Objective-C 옵셔널 수식어 추가

5. Swift 2.0
에러처리 throw, do try catch
guard let ­ else
프로토콜 익스텐션
Objective-C 제네릭

6. Swift 3.0
예상 발표일: 2016 말
Swift 언어와 개발 경험 강화
Swift 3.0과 이후 버전의 소스 호환성
http://bekher.net/2015/06/the-next-step-for-swift/

7. Swift 3.0 Focus
API 디자인 가이드라인
임포트한 Obj-C API에 네이밍 가이드라인 자동 적용
핵심 API에 네이밍 가이드라인 도입
임포트한 Obj-C API의 Swift화
언어의 집중 및 정교화
툴 품질 향상

9. API Design Guideline
기본 원칙
사용 시점의 명확성
짧은 것보다 명확한 것이 더 중요
모든 선언마다 주석으로 문서화

10. Swift Evolution
Language Evolution Process
Socialize ➔ Proposal(PR) ➔ Review ➔ Decision
Swift Evolution Process
https://swift.org/community/#mailing-lists
https://lists.swift.org/mailman/listinfo/swift-evolution
https://github.com/apple/swift-
evolution#implemented-proposals-for-swift-3

13. Swift Evolution: Example
SE-0031: Adjusting inout Declarations for Type
Decoration
메일링 리스트 논의
PR
SE 수락

18. SE-0031
Adjusting 'inout' Declarations for Type
Decoration
Swift 2
Swift 3
(x: inout T) -> U // => (inout T) -> U
func foo(inOut x: T) // foo(inOut:), type (T) -> Void
func foo(inout x: T) // foo(_:), type (inout T) -> Void

19. letswift(16)
Core Language

20. Swift 3 Removals
SE-0002: Removing currying func declaration syntax
SE-0003: Removing var from Function Parameters
SE-0004: Remove the ++ and -- operators
SE-0007: Remove C-style for-loops with conditions and
incrementers
SE-0029: Remove implicit tuple splat behavior from function
applications
SE-0053: Remove explicit use of let from Function Parameters

21. SE-0003:
Removing var from Function Parameters
func foo(i: Int) {
i += 1 // illegal
}
func foo(var i: Int) {
i += 1 // OK, but the caller cannot observe this mutation.
}
func doSomethingWithVar(var i: Int) {
i = 2 // This will NOT have an effect on the
caller's Int that was passed, but it can be modified
locally
}
func doSomethingWithInout(inout i: Int) {
i = 2 // This will have an effect on the caller's
Int that was passed.
}
var x = 1
print(x) // 1
doSomethingWithVar(x)
print(x) // 1
doSomethingWithInout(&x)
print(x) // 2

22. SE-0003:
기존 코드
func foo(i: Int) {
var i = i
}

23. Swift 3 Functions
SE-0042: Flattening the function type of unapplied method references
SE-0046: Establish consistent label behavior across all parameters
including first labels
SE-0047: Defaulting non-Void functions so they warn on unused
results
SE-0066: Standardize function type argument syntax to require
parentheses
SE-0110: Distinguish between single-tuple and multiple-argument
function types
SE-0111: Remove type system significance of function argument labels

24. SE-0046
Establish consistent label behavior across all
parameters including first labels
Swift 2
Swift 3
func foo(a: T, b: U, c: V)
foo(_:b:c:)
func foo(a: T, b: U, c: V)
foo(a:b:c:)
func foo(_: T, b: U, c: V)
foo(_:b:c:)

25. SE-0110
Distinguish between single-tuple and multiple-
argument function types
Swift 2
Swift 3
let fn1 : (Int, Int) -> Void = { x in
// The type of x is the tuple (Int, Int).
// ...
}
let fn2 : (Int, Int) -> Void = { x, y in
// The type of x is Int, the type of y is Int.
// ...
}
let a : ((Int, Int, Int)) -> Int = { x in return x.0 + x.1 + x.2 }

26. Swift 3 Optional
SE-0008: Add a Lazy flatMap for Sequences of
Optionals
SE-0054: Abolish ImplicitlyUnwrappedOptional
type
SE-0055: Make unsafe pointer nullability explicit
using Optional

27. Swift 3 Debugging & Testing
SE-0019: Swift Testing
SE-0028: Modernizing Swift's Debugging
Identifiers (__FILE__, etc)
SE-0034: Disambiguating Line Control
Statements from Debugging Identifiers
SE-0039: Modernizing Playground Literals

28. Modernizing Swift's Debugging Identifiers
Swift offers built-in __FILE__, __LINE__, __COLUMN__,
__FUNCTION__, and __DSO_HANDLE__ identifiers
__FILE__ ➔ #file
__LINE__ ➔ #line
__COLUMN__ ➔ #column
__FUNCTION__ ➔ #function (Added during review)
__DSO_HANDLE__ ➔ #dsohandle
SE-0028

29. Swift 3 Swift Library
SE-0016: Adding initializers to Int and UInt to convert
from UnsafePointer and UnsafeMutablePointer
SE-0032: Add first(where:) method to SequenceType
SE-0052: Change IteratorType post-nil guarantee
SE-0065: A New Model For Collections and Indices
SE-0094: Add sequence(first:next:) and
sequence(state:next:) to the stdlib

30. letswift(16)
API & Foundation

31. Swift 3 API Design Guidelines
Swift API Design Guidelines
SE-0005: Better Translation of Objective-C APIs Into
Swift
SE-0006: Apply API Guidelines to the Standard
Library
SE-0023: API Design Guidelines
SE-0059: Update API Naming Guidelines and Rewrite
Set APIs Accordingly

32. SE-0005
Better Translation of Objective-C APIs Into Swift
Objective-C API
Swifty version
let content = listItemView.text.stringByTrimmingCharactersInSet(
NSCharacterSet.whitespaceAndNewlineCharacterSet())
let content = listItemView.text.trimming(.whitespaceAndNewlines)

33. SE-0005
UIBezierPath in Swift 2
class UIBezierPath : NSObject, NSCopying, NSCoding {
convenience init(ovalInRect: CGRect)
func moveToPoint(_: CGPoint)
func addLineToPoint(_: CGPoint)
func addCurveToPoint(_: CGPoint, controlPoint1: CGPoint, controlPoint2: CGPoint)
func addQuadCurveToPoint(_: CGPoint, controlPoint: CGPoint)
func appendPath(_: UIBezierPath)
func bezierPathByReversingPath() -> UIBezierPath
func applyTransform(_: CGAffineTransform)
var empty: Bool { get }
func containsPoint(_: CGPoint) -> Bool
func fillWithBlendMode(_: CGBlendMode, alpha: CGFloat)
func strokeWithBlendMode(_: CGBlendMode, alpha: CGFloat)
func copyWithZone(_: NSZone) -> AnyObject
func encodeWithCoder(_: NSCoder)
}

34. SE-0005
UIBezierPath in Swift 3
class UIBezierPath : NSObject, NSCopying, NSCoding {
convenience init(ovalIn rect: CGRect)
func move(to point: CGPoint)
func addLine(to point: CGPoint)
func addCurve(to endPoint: CGPoint, controlPoint1 controlPoint1: CGPoint,
controlPoint2 controlPoint2: CGPoint)
func addQuadCurve(to endPoint: CGPoint, controlPoint controlPoint: CGPoint)
func append(_ bezierPath: UIBezierPath)
func reversing() -> UIBezierPath
func apply(_ transform: CGAffineTransform)
var isEmpty: Bool { get }
func contains(_ point: CGPoint) -> Bool
func fill(_ blendMode: CGBlendMode, alpha alpha: CGFloat)
func stroke(_ blendMode: CGBlendMode, alpha alpha: CGFloat)
func copy(with zone: NSZone = nil) -> AnyObject
func encode(with aCoder: NSCoder)
}

35. SE-0006
Strip Type Suffix from protocol names
-public protocol BooleanType { ... }
+public protocol Boolean { ... }
-public protocol SequenceType { ... }
+public protocol Sequence { ... }
-public protocol CollectionType : ... { ... }
+public protocol Collection : ... { ... }
-public protocol MutableCollectionType : ... { ... }
+public protocol MutableCollection : ... { ... }
-public protocol RangeReplaceableCollectionType : ... { ... }
+public protocol RangeReplaceableCollection : ... { ... }
-public protocol AnyCollectionType : ... { ... }
+public protocol AnyCollectionProtocol : ... { ... }
-public protocol IntegerType : ... { ... }
+public protocol Integer : ... { ... }

36. SE-0006
renamed functions
sort() ➔ sorted()
sortInPlace() ➔ sort()
reverse() ➔ reversed()
enumerate() ➔ enumerated()

37. SE-0006
New importing rules
extension String {
- public static func localizedNameOfStringEncoding(
- encoding: NSStringEncoding
- ) -> String
+ public static func localizedName(
+ ofStringEncoding encoding: NSStringEncoding
+ ) -> String
- public static func pathWithComponents(components: [String]) -> String
+ public static func path(withComponents components: [String]) -> String
- public init?(UTF8String bytes: UnsafePointer<CChar>)
+ public init?(utf8String bytes: UnsafePointer<CChar>)
- public func canBeConvertedToEncoding(encoding: NSStringEncoding) -> Bool
+ public func canBeConverted(toEncoding encoding: NSStringEncoding) -> Bool
- public var capitalizedString: String
+ public var capitalized: String
- public var localizedCapitalizedString: String
+ public var localizedCapitalized: String

38. Swift 3 Foundation
SE-0069: Mutability and Foundation Value
Types
SE-0086: Drop NS Prefix in Swift Foundation

39. SE-0069
Mutability and Foundation Value Types
Objective-C API
let myDate = Date()
let myLaterDate = myDate.dateByAddingTimeInterval(60)
var myDate = Date()
myDate.addTimeInterval(60) // OK
let myOtherDate = Date()
myOtherDate.addTimeInterval(60) // Error, as expected

40. SE-0086
Drop NS Prefix in Swift Foundation
Objective-C Name Swift Name
NSAttributedString AttributedString
NSBlockOperation BlockOperation
NSBundle Bundle
NSByteCountFormatter ByteCountFormatter
NSCache Cache
NSCacheDelegate CacheDelegate
NSCachedURLResponse CachedURLResponse
NSCalendar Calendar
NSComparisonPredicate ComparisonPredicate
NSComparisonResult ComparisonResult
NSCompoundPredicate CompoundPredicate

41. SE-0086
Enumerations
extension DateIntervalFormatter {
@available(OSX 10.10, iOS 8.0, *)
public enum Style : UInt {
case none
case short
case medium
case long
case full
}
}
extension NumberFormatter {
public enum Style : UInt {
case none
case decimal
case currency
case percent
case scientific
case spellOut
@available(OSX 10.11, iOS 9.0, *)
case ordinal
@available(OSX 10.11, iOS 9.0, *)
case currencyISOCode
@available(OSX 10.11, iOS 9.0, *)
case currencyPlural
@available(OSX 10.11, iOS 9.0, *)
case currencyAccounting
}
}

42. Swift 3 Objective-C
SE-0062: Referencing Objective-C key-paths
SE-0064: Referencing the Objective-C selector of
property getters and setters
SE-0070: Make Optional Requirements Objective-C-
only
SE-0033: Import Objective-C Constants as Swift
Types
SE-0057: Importing Objective-C Lightweight Generics

43. References
https://en.wikipedia.org/wiki/
Swift_(programming_language)
https://swift.org/documentation/api-design-guidelines/
https://developer.apple.com/videos/play/wwdc2016/402/
https://developer.apple.com/videos/play/wwdc2016/207/
https://github.com/apple/swift-evolution#implemented-
proposals-for-swift-3
https://www.raywenderlich.com/135655/whats-new-swift-3

44. –Johnny Appleseed
“Swift 3 is awesome.”

45. letswift(16)