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KeyPathͷศརͳ͍ಓΛ
ݚڀ͢Δ
Otemachi.swift x Kyobashi.swift #01
Katsumi Kishikawa
[email protected]
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KeyPath in Swift 3
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#keyPath(Book.title)
#keyPath(Book.price)
#keyPath(Book.author.name)
@objcMembers
class Book {
var isbn: String
var title: String
var price: Int
var author: Author
...
}
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KeyPath in Swift 3
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let titleKeyPath: String = #keyPath(Book.title)
let priceKeyPath: String = #keyPath(Book.price)
let authorNameKeyPath: String = #keyPath(Book.author.name)
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KeyPath in Swift 3
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let title: Any? = book.value(forKeyPath: #keyPath(Book.title))
let price: Any? = book.value(forKeyPath: #keyPath(Book.price))
let authorName: Any? = book.value(forKeyPath: #keyPath(Book.author.name))
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Smart KeyPath in Swift 4
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struct Book {
let isbn: String
let title: String
let price: Int
let author: Author
}
struct Author {
let name: String
let age: Int?
let birthday: Date?
}
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Smart KeyPath in Swift 4
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struct Book {
let isbn: String
let title: String
let price: Int
let author: Author
}
struct Author {
let name: String
let age: Int?
let birthday: Date?
}
let book = Book(isbn: "978-4774188485",
title: "Realmೖ",
price: 3110,
author: Author(name: "ੁݪ ༞", age: nil, birthday: nil))
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Smart KeyPath in Swift 4
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let book = Book(isbn: "978-4774188485",
title: "Realmೖ",
price: 3110,
author: Author(name: "ੁݪ ༞", age: nil, birthday: nil))
let title = book[keyPath: \Book.title] // => "Realmೖ"
let price = book[keyPath: \Book.price] // => 3110
let authorName = book[keyPath: \Book.author.name] // "ੁݪ ༞"
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Smart KeyPath in Swift 4
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let title = book[keyPath: \Book.title] // => "Realmೖ"
let price = book[keyPath: \Book.price] // => 3110
let authorName = book[keyPath: \Book.author.name] // "ੁݪ ༞"
\Book.title
\Book.price
\Book.author.name
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[email protected]
let titleKeyPath: KeyPath = \Book.title
let priceKeyPath: KeyPath = \Book.price
let authorNameKeyPath: KeyPath = \Book.author.name
Smart KeyPath in Swift 4
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let title: String = book[keyPath: \Book.title]
let price: Int = book[keyPath: \Book.price]
let authorName: String = book[keyPath: \Book.author.name]
Smart KeyPath in Swift 4
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ϓϩύςΟΞΫηε
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let title = book.title // => "Realmೖ"
let price = book.price // => 3110
let authorName = book.author.name // "ੁݪ ༞"
΄ͱΜͲͷέʔεϓϩύςΟΞΫηεͷํ͕؆୯͔ͭద͍ͯ͠ΔͷͰɺ
KVOͳͲݹ͍ΈͷޓੑҎ֎ͷతͰΘ͟Θ͟KeyPathΛ͏໘গͳ͍
̍ͭNSPredicateͳͲϓϩύςΟͷใΛจࣈྻͰΈཱ͍ͯͯΔΑ͏ͳ
APIΛ҆શʹॻ͚ΔΑ͏ʹ͢Δ͜ͱ͕Ͱ͖ͦ͏ɻ
ଞʹศརͳར༻ํ๏͋ΔͩΖ͏͔ʁ
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Type-unsafe KVO in Swift 3
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book.addObserver(self, forKeyPath: #keyPath(Book.price), options: [], context: nil)
override func observeValue(forKeyPath keyPath: String?,
of object: Any?,
change: [NSKeyValueChangeKey : Any]?,
context: UnsafeMutableRawPointer?) {
if keyPath == "price" {
if let book = object as? Book {
if book.price < 2000 {
}
}
}
}
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Type-safe KVO
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book.observe(\Book.price) { (observed, change) in
if (observed.price < 2000) {
}
}
KVOΛੵۃతʹ͏͜ͱͳ͍͚ΕͲɺiOSϓϩάϥϛϯάͰ·ͩඞཁʹͳΔɻ
ࠓճͷվળʹΑΓΩϟετ͕ෆཁʹͳΔͳͲɺSwiit͔Βඇৗʹѻ͍͘͢ͳͬͨɻ
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Type-unsafe Query in Swift 4
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NSPredicate(format: "name == %@", "Katsumi")
NSPredicate(format: "age > %@", 20)
NSPredicate(format: "nsme == %@", "Katsumi") // Runtime Error
NSPredicate(format: "name > %@", 20) // Runtime Error
NSPredicateͳͲϓϩύςΟͷใΛจࣈྻͰࢦఆ͢Δඞཁ͕͋ΔAPIΛ
KeyPathΛͬͯΑΓ҆શʹॻ͚Δ
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Type-safe Query
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Query(Person.self).filter(\Person.name == "Katsumi")
Query(Person.self).filter(\Person.age > 20)
Query(Person.self).filter(\Person.name > 20) // Compile error
Query(Person.self).filter(\Dog.name == "John") // Compile error
KeyPathίϯύΠϥͷνΣοΫ͕ಇ͘ͷͰɺTypo͕ͳ͘ͳΔʢίʔυิՄೳʣ
͜ͱͪΖΜɺܕνΣοΫػೳ͢Δɻ
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Type-safe Query
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...
public func == (lhs: KeyPath, rhs: String) -> BasicPredicate {
return BasicPredicate(format: "%K == %@",
arguments: [lhs._kvcKeyPathString! as NSString, rhs as NSString])
}
public func != (lhs: KeyPath, rhs: String) -> BasicPredicate {
return BasicPredicate(format: "%K != %@",
arguments: [lhs._kvcKeyPathString! as NSString, rhs as NSString])
}
public func < (lhs: KeyPath, rhs: Property) -> BasicPredicate {
return BasicPredicate(format: "%K < %@",
arguments: [lhs._kvcKeyPathString! as NSString, rhs as! NSNumber])
}
public func > (lhs: KeyPath, rhs: Property) -> BasicPredicate {
return BasicPredicate(format: "%K > %@",
arguments: [lhs._kvcKeyPathString! as NSString, rhs as! NSNumber])
}
...
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Type-safe Query (for Realm)
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@objcMembers
class Dog: Object {
dynamic var name = ""
dynamic var age = 0
dynamic var owner: Person!
let owners = LinkingObjects(fromType: Person.self, property: "dogs")
}
@objcMembers
class Person: Object {
dynamic var name = ""
dynamic var age = 0
dynamic var birthdate = Date()
let dogs = List()
}
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Type-safe Query (for Realm)
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realm.objects(Person.self)
.filter { \Person.name == "Katsumi" }
realm.objects(Dog.self)
.filter { \Dog.age < 2 }
realm.objects(Dog.self)
.filter { \Dog.name < 2 } // ❌
realm.objects(Dog.self)
.filter { \Person.age < 2 } // ❌
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t>(lhs: KeyPath, rhs: String) ->
ect>(format: "%K == %@", arguments: [lhs._kvcKeyPathString! as NSString, rhs
, RealmProperty: Numeric>(lhs: KeyPath, rhs:
ealmObject> {
ect>(format: "%K < %@", arguments: [lhs._kvcKeyPathString! as NSString, rhs
, RealmProperty: Numeric>(lhs: KeyPath, rhs:
ealmObject> {
ect>(format: "%K > %@", arguments: [lhs._kvcKeyPathString! as NSString, rhs
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ݱࡏKeyPathͷจࣈྻදݱඇެ։ͳͷͰ͑ΔΑ͏ʹͯ͠΄͍͠ͱ͍͏ϦΫΤετΛ
ग़͍ͯ͠Δ
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Lensͱ
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• ؔܕϓϩάϥϛϯάʹ͓͍ͯGetter/SetterΛநԽ͢ΔσβΠϯύλʔϯ
• ෆมੑΛอͬͨ··ෳࡶͳσʔλߏͷ༰қͳΞΫηεΛఏڙ͢Δ
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ΦϒδΣΫτࢦݴޠͳΒ...
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let title = book.title
let price = book.price
let authorName = book.author.name
book.author.name = "..."
Lensͦͦؔܕϓϩάϥϛϯάʹ͓͍ͯΦϒδΣΫτࢦݴޠͷػೳΛ
ΤϛϡϨʔτ͢ΔͷͳͷͰɺSwiftʹಋೖͯ͠ศརͳ͋ΔͷͩΖ͏͔ʁ
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Lenses in Swift
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struct BoardingPass {
let plane: Plane
let gate: Gate
let departureDate: Date
let arrivalDate: Date
}
struct Plane {
let model: String
let freeSeats: Int
let takenSeats: Int
let status: Status
}
struct Gate {
let number: Int
let letter: String
}
enum Status {
case early
case onTime
case late
}
// https://github.com/typelift/Focus
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Lenses in Swift
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let plane = Plane(model: "SpaceX Raptor", freeSeats: 4, takenSeats: 0, status: .onTime)
let gate = Gate(number: 1, letter: "A")
let pass = BoardingPass(plane: plane,
gate: gate,
departureDate: Date.distantFuture,
arrivalDate: Date.distantFuture)
// https://github.com/typelift/Focus
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Lenses in Swift
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let newPlane = Plane(model: pass.plane.model,
freeSeats: pass.plane.freeSeats,
takenSeats: pass.plane.takenSeats,
status: .late)
let newPass = BoardingPass(plane: newPlane,
gate: pass.gate,
departureDate: pass.departureDate,
arrivalDate: pass.arrivalDate)
▿ BoardingPass
▿ plane: Plane
- model: "SpaceX Raptor"
- freeSeats: 4
- takenSeats: 0
- status: Status.late
▿ gate: Gate
- number: 1
- letter: "A"
- departureDate: 4001-01-01 00:00:00 +0000
- arrivalDate: 4001-01-01 00:00:00 +0000
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Lenses in Swift
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var pass = BoardingPass(plane: plane,
gate: gate,
departureDate: Date.distantFuture,
arrivalDate: Date.distantFuture)
pass.plane.status = .late
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Lenses in Swift
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let newPass = pass |>
(\BoardingPass.plane.status) .~ .late
Lensͦͦؔܕϓϩάϥϛϯάʹ͓͍ͯΦϒδΣΫτࢦݴޠͷػೳΛ
ΤϛϡϨʔτ͢ΔͷͳͷͰɺSwiftʹಋೖͯ͠ศརͳ͋ΔͷͩΖ͏͔ʁ
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Lenses in Swift
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let newPass = pass |>
(\BoardingPass.plane.status) .~ .late
▿ BoardingPass
▿ plane: Plane
- model: "SpaceX Raptor"
- freeSeats: 4
- takenSeats: 0
- status: Status.late
▿ gate: Gate
- number: 1
- letter: "A"
- departureDate: 4001-01-01 00:00:00 +0000
- arrivalDate: 4001-01-01 00:00:00 +0000
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LensͰςετΛΘ͔Γ͘͢
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func testUser() {
let templateUser = User(name: "Katsumi Kishikawa", age: 37, sns: SNS(twitter: "k_katsumi", facebook: nil))
XCTContext.runActivity(named: "User is student") { (activity) in
let studentUser = User(name: templateUser.name, age: 37, sns: templateUser.sns)
...
XCTAssert(...)
}
XCTContext.runActivity(named: "...") { (activity) in
let silverUser = User(name: templateUser.name, age: 65, sns: templateUser.sns)
...
XCTAssert(...)
}
}
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LensͰςετΛΘ͔Γ͘͢
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func testUser() {
let templateUser = User(name: "Katsumi Kishikawa", age: 37, sns: SNS(twitter: "k_katsumi", facebook: nil))
XCTContext.runActivity(named: "User is student") { (activity) in
let studentUser = user |> (\User.age) .~ 15
...
XCTAssert(...)
}
XCTContext.runActivity(named: "...") { (activity) in
let silverUser = user |> (\User.age) .~ 65
...
XCTAssert(...)
}
}
LensʹΑͬͯಛఆͷϓϩύςΟ͚ͩΛมߋͰ͖ΔͷͰ
ྸʹϑΥʔΧε͍ͯ͠Δ͜ͱ͕ΑΓΘ͔Γ͍͢ʁ
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LensͰςετΛΘ͔Γ͘͢
[email protected]
Quick + LensΛ༻͍ͨςετͷߏԽ
https://speakerdeck.com/nonchalant/quick-plus-lenswoyong-itatesutofalsegou-zao-hua
kickstarter/ios-oss
https://github.com/kickstarter/ios-oss/blob/3e112451a306c27319704e5a67d4edea7ed66014/Kickstarter-iOS/Views/Controllers/ActivitiesViewControllerTests.swift#L9-L15
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Questions?
Katsumi Kishikawa
[email protected]
www.realm.io
@k_katsumi
[email protected]