objc2swift 〜 Objective-C から Swift への「コード＆パラダイム」シフト

objc2swift Objective-C Swift &

@taketo1024

2015/11/11 iOS 9 Bootcamp @ dots. by Classmethod, inc.

About Me

() iOS iOS 4 (Xcode 3.x ) 31 1()

11/21 () 5 11/15 ()

Objective-C Swift

1 ObjC iOS

44 iOS

Swift

Bridging-Header

ObjC Swift

ObjC Swift

Swift

ObjC Swift

ObjC Swift

@interface MyClass class MyClass

@property NSString *text; var text: String

@protocol MyProtocol protocol MyProtocol

@interface MyClass(Hoge) extension MyClass

2

ANTLR...?

ANTLR v4

http://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.orghttp://www.antlr.org

ANTLR Parser

2 ANTLR

ANTLR ObjC

Swift

Java Scala

class A : NSObject {

}

Swift

merge .h & .m

@interface MyClass : NSObject

@end

@implementation MyClass

@end Obj-C

Obj-C Swift

convert method-call

self.somethingWithArg1("hello", arg2:0)

Swift

[self somethingWithArg1:@"hello" arg2:0];

Obj-C

control-flow

for var i = 0; i < 10; i++ {

}

Swift

for (int i = 0; i < 10; i++) {

}

Obj-C

& many more! primitive-types

class-method

enum

protocol

property

block -> closure

stringWithFormat

error reporting

Web UI

20%

40%

40%

20%

80%

N=5N=5

SwiftObjective-CSwift

Swift Objective-C Swift objc2swift

Scala

DEMO

OpenSourced

https://github.com/yahoojapan/objc2swift

WebUI

https://github.com/yahoojapan/objc2swift

Goodbye ObjC !!!

No more too many @s! No more YES / NO ! No more [brackets forMethodCall] !

https://twitter.com/marcote_torres/status/473536682353262592/photo/1

Swift

So many ? s... So many if let s... unexpectedly found nil while blabla...

let result = try? NSJSONSerialization.JSONObjectWithData()

let name = ((result?["person"] as? [String: AnyObject])?["name"] as? String)

if let name = name { print("My name is: \(name)") }

Swift Swift ObjC Objective-C without the C ...? wtf

Swift

ObjC / Foundation

Swift Swift

0. Swift

1. Optional

2. First-Class

3. Protocol Oriented

0. Swift

Objective-C

19831985 Apple Steve Jobs NeXT Computer

1997Apple NeXT 2001 Mac OS X Cocoa

Foundation NS OS NeXTSTEP

ObjC C Smalltalk

C C

ObjC @ C

typedef struct objc_class *Class; struct objc_class {

struct objc_class *isa;

struct objc_class *super_class;

const char *name;

};

typedef struct objc_object {

class isa;

} *id;

2005Objective-C -

http://news.mynavi.jp/column/objc/014/

Obj-C

Objective-C Swift

GCC

Objective-C

1983

GCC

Objective-C 2.0

2007

LLVM

ModernObjective-C

2012

Swift 1.0

2014

SwiftApple

LLVM

Clang swiftc

Apple LLVM Swift

http://codezine.jp/article/detail/8768

Swift ()

Objective-C

The Swift language also greatly benefited from the experiences hard-won by many other languages in the field, drawing ideas from Objective-C, Rust, Haskell, Ruby, Python, C#, CLU, and far too many others to list.

http://nondot.org/sabre/

Chris Lattner

ObjC

Strongly Typed (w/ Optional Type)

Functional

Protocol-Oriented

1. Optional

Apple

if let johnsStreet = john.residence?.address?.street { print("John's street name is \(johnsStreet).") } else { print("Unable to retrieve the address.") }

Swift also introduces optional types, which handle the absence of a value. Optionals say either there is a value, and it equals x or there isnt a value at all. Using optionals is similar to using nil with pointers in Objective-C, but they work for any type, not just classes.

nil ?

nil ?

public enum Optional : NilLiteralConvertible { case None case Some(Wrapped) }

Optional enum Int? Optional

Optional Optional

nil Optional None

Swift Standard Library

Optional

Functors, Applicatives, And Monads In Pictures

http://adit.io/posts/2013-04-17-functors,_applicatives,_and_monads_in_pictures.html

Optional 0 1 Array

let maybeInt : Optional = .Some(1)

let actualInt = maybeInt!

let maybeInt : Optional = 1

let actualInt = maybeInt!

let maybeInt : Optional = .Some(1)

let actualInt = maybeInt!

let actualInt = maybeInt!

let maybeInt : Array = [1]

let actualInt = maybeInt[0]

let maybeInt : Optional = nil

let actualInt = maybeInt! // fatal error: unexpectedly found nil while unwrapping an Optional value

let maybeInt : Array = []

let actualInt = maybeInt[0] // fatal error: Array index out of range

nil

let maybeInt : Optional = .Some(1)

if let actualInt = maybeInt { print("int: \(actualInt)") }

let maybeInt : Array = [1]

for actualInt in maybeInt { print("int: \(actualInt)") }

if let 1 for in for

Swift Optional

Optional Objective-C nil

Optional

guard let

let maybeInt: Optional = 1

guard let actualInt = maybeInt else { fatalError() }

print("value: \(actualInt)")

guard let

let value: Optional = 1

guard let value = value else { fatalError() }

print("value: \(value)")

unwrap

guard let

let value: Optional = 1 guard let value = value else { fatalError() }

print("value: \(value)")

!!!

Optional

Int

guard let

2. First-Class

let a = [2, 3, 1, 4]

a.sort() // [4, 3, 2, 1]

let a = [2, 3, 1, 4]

a.sort() // [4, 3, 2, 1]

sort (T, T) -> Bool

let a = [2, 3, 1, 4]

let lt: (Int, Int) -> Bool = (

ObjC Swift

let a = [2, 3, 1, 4] // [2, 3, 1, 4] let b = a.map {$0 * 2} // [4, 6, 2, 8] let c = b.filter {$0 < 5} // [4, 2]

map filter

override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? { var result = [UICollectionViewLayoutAttributes]() for i in 0 ..< items.count { let indexPath = NSIndexPath(forItem: i, inSection: 0) let attr = layoutAttributesForItemAtIndexPath(indexPath)

if attr.alpha == 0 { continue } if !CGRectIntersectsRect(attr.frame, rect) { continue } result.append(attr) } return result }

map filter

before

override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? { let indexPaths = (0 ..< items.count).map { NSIndexPath(forItem: $0, inSection: 0) } let attrs = indexPaths.map( layoutAttributesForItemAtIndexPath )

let attrsInScreen = attrs.filter { $0.alpha > 0 } .filter{ CGRectIntersectsRect($0.frame, rect)}

return attrsInScreen }

map filter

after

override func layoutAttributesForElementsInRect(rect: CGRect) -> [UICollectionViewLayoutAttributes]? { return (0 ..< items.count) .map { NSIndexPath(forItem: $0, inSection: 0) } .map ( layoutAttributesForItemAtIndexPath ) .filter { $0.alpha != 0 } .filter { CGRectIntersectsRect($0.frame, rect)} }

let a : Optional = 1 // .Some(1) let b = a.map { $0 * 2 } // .Some(2)

Optional map

.Some(1) [1]

let a : Optional = "1" // .Some("1") let b = a.map { Int($0) } // .Some( .Some(1) )

let s : Optional = "hehe" // .Some("hehe") let t = s.map { Int($0) } // .Some( .None )

map Optional 2

String -> Int Optional

let a : Optional = "1" // .Some("1") let b = a.flatMap { Int($0) } // .Some(1)

let s : Optional = "hehe" // .Some("hehe") let t = s.flatMap { Int($0) } // .nil

flatMap !

let a = ["1", "2", "heh", "4", "lol"] let b = a.flatMap{ Int($0) } // [1, 2, 4]

Optional flatMap filter

https://codeiq.jp/magazine/2015/07/27113/

ObjC Swift

Scala Haskell

Promise ReactiveUI

3. Protocol-Oriented

WWDC2015 - Protocol-Oriented Programming in Swift

https://developer.apple.com/videos/play/wwdc2015-408/

Swift is the first protocol oriented language.

Swift protocol

Java interface

Scala trait mix-in

Haskell type class AdHoc

Haskell class Eq a where (==), (/=) :: a -> a -> Bool x == y = not (x /= y) x /= y = not (x == y)

data Point = Pt Double Double

instance Eq Point where (Pt x y) == (Pt x' y') = x == x' && y == y'

Eq

Point Eq

http://walk.wgag.net/haskell/typeclass.html

http://walk.wgag.net/haskell/typeclass.html

public protocol Equatable {

public func ==(lhs: Self, rhs: Self) -> Bool

}

struct Point: Equatable { let x, y: Double }

func ==(p1: Point, p2: Point) -> Bool { return p1.x == p2.x && p1.y == p2.y }

Equatable

Point Equatable

Scala / Haskell U Protocol

protocol AddMonoid { static var zero: Self { get } static func plus(lhs: Self, _ rhs: Self) -> Self }

extension Int: AddMonoid { static var zero: Int { return 0 } static func plus(lhs: Int, _ rhs: Int) -> Int { return lhs + rhs } }

extension String: AddMonoid { static var zero: String { return "" } static func plus(lhs: String, _ rhs: String) -> String { return lhs + rhs } }

extension SequenceType where Generator.Element: AddMonoid { func sum() -> Generator.Element { return reduce(Generator.Element.zero) { Generator.Element.plus($0, $1) } } }

[1, 2, 3].sum() // 6 ["abc", "def", "ghi"].sum() // "abcdefghi"

class-oriented vs protocol-oriented ()

struct

Protocol

protocolA

protocolB

protocol-oriented

Swift protocol-oriented Foundation / UIKit

Self Requirement

protocol MyProtocol: Equatable {}

struct A: MyProtocol {} struct B: MyProtocol {}

let a: [MyProtocol] = [A(), B()] // protocol 'MyProtocol' can only be used as a generic constraint because it has Self or associated type requirements

extension protocol-oriented

Swift Foundation / UIKit

()

Thanks!

Twitter: taketo1024Blog: http://taketo1024.hateblo.jp/

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