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REACTIVECOCOAೖ
Signals, SignalProducers and Events! Oh my!
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ࣗݾհ
Nicholas Maccharoli (χίϥεɾϚΧϩʔϦ)
VASILYͰiOSΤϯδχΞΛ͍ͯ͠·͢
OSSͱ͔Swift Evolutionʹߩݙ͍ͯ͠·͢
࠷ۙSwift Evolution SE-0053ΛఏҊͯ͠Swift3.0ʹ
࠾༻͞Ε·ͨ͠ʂ
github.com/nirma
@din0sr
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FRP(FUNCTIONAL REACTIVE PROGRAMMING)
ͷϝϦοτʁ
> ίʔυϊΠζ͕ݮΒͤ·͢
> @IBAction, NSNotificationCenter͓ΑͼCallback/
DelegateͷύλʔϯΑΓɺͬͱγϯϓϧ
ͳ࣮͕Ͱ͖·͢ɻ
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ྫ: ϦϑϨογϡϘλϯͷΫϦοΫΠϕϯτ
(Ұൠతͳ࣮)
@IBAction func refreshButtonClicked(sender: AnyObject) {
updateViewForState(.Loading)
performNetworkRequest() {
updateModel()
dispatch_async(dispatch_get_main_queue()) {
updateViewForState(.Success)
}
}
}
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refreshButtonClicked:͕ݺΕͨΒ
1. ϘλϯͷදࣔΛߋ৽
2. ϩʔσΟϯάΞΠίϯΛදࣔ
3. ωοτϫʔΫϦΫΤετ
4. ϦΫΤετ͕ྃͨ͠ΒCallbackͰUIͱϞσ
ϧΛߋ৽͢Δ
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Ұͭͷϝιουͷதʹෳͷͷॲཧ͕
ݻ·͍ͬͯͯྑ͘ͳ͍ɻ
γϯϓϧʹॻ͖͍͑ͨɻ
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ϧʔϓॲཧͩͱ͜ΜͳΠϝʔδ
Before:
var counter = 0
var animationImages = [UIImage]()
while counter < 10 {
let imageString = "animation_image_\(counter)"
if let image = UIImage(named: imageString) {
animationImages += [image]
}
}
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ϧʔϓॲཧͩͱ͜ΜͳΠϝʔδ
After:
(0..<10).flatMap { UIImage(named: "animation_image_\($0)") }
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RAC FTW!
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REACTIVECOCOAͱRXͷҧ͍
> Naming Convention
> Rx: Hot Observable, Cold Observable
> ReactiveCocoa: Signal, SignalProducer
> Cocoaઐ༻API֦ு
> ΑΓγϯϓϧͳઃܭ
> etc
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YES, SIGNALS!
SignalͰΠϕϯτΛड͚औͬͯObserverͱ͔
DisposableͰSignalૢ࡞͕Ͱ͖·͢ɻ
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EVENTS...
/// Signals must conform to the grammar:
/// `Next* (Failed | Completed | Interrupted)?`
public enum Event {
/// A value provided by the signal.
case Next(Value)
/// The signal terminated because of an error. No further events will be
/// received.
case Failed(Error)
/// The signal successfully terminated. No further events will be received.
case Completed
/// Event production on the signal has been interrupted. No further events
/// will be received.
case Interrupted
/// Whether this event indicates signal termination (i.e., that no further
/// events will be received).
}
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SIGNALS, CHEAP
ৗʹൃੜ͠͏ΔΠϕϯτετϦʔϜ
> UIίϯτϩʔϧ
> APIϦΫΤετ
> DB Read / Write
> UINotificationCenter
> ͳΜͰ
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SIGNAL࡞ͱ͍ํ
let (userNameTextSignal, observer) = Signal.pipe()
userNameTextSignal.observeNext { userName in
print("Next Event: \(userName)")
}
observer.sendNext("l") // Next Event: l
observer.sendNext("la") // NExt Event: la
observer.sendNext("lat") // Next Event: lat
observer.sendNext("latt") // Next Event: latn
observer.sendNext("lattn") // Next Event: lattn
observer.sendNext("lattne") // Next Event: lattne
observer.sendNext("lattner") // Next Event: lattner
observer.sendCompleted()
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SIGNAL'S FRIENDS MAP, FILTER, REDUCE
RAC Marbles
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SIGNAL OPERATORS IN ACTION - FILTER
let (userNameTextSignal, observer) = Signal.pipe()
let improvedUserNameTextSignal = userNameTextSignal.filter { $0.characters.count > 4 }
improvedUserNameTextSignal.observeNext { userName in
print("Next Event: \(userName)")
}
observer.sendNext("lattn")
observer.sendNext("lattne")
observer.sendNext("lattner")
observer.sendCompleted()
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طଘͷSIGNAL͔Β৽͍͠SIGNALΛ࡞Δ
let (userNameTextSignal, observer) = Signal.pipe()
let userNameValidSignal = userNameTextSignal.map {
return $0.characters.count > 5
}
let backgroundColorSignal = userNameValidSignal.map {
return $0 ? UIColor.greenColor() : UIColor.redColor()
}
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SIGNALS & END OF LIFE
swiftͷGeneratorTypeͱಉ͡Α͏ʹҰճSignal
Λ͍ऴΘͬͨΒ࠶ར༻Ͱ͖ͳ͍ɻ
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SIGNALPRODUCER (COLD SIGNALS)
> SignalProducers Signal ͷϑΝΫτϦʔ
> ߪಡ͠ͳ͍͔͗Γɺॲཧ։࢝͞Εͳ͍
> Signal Operators can be 'Lifted'
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SIGNALPRODUCER - NOTHING
var userNameProducer = SignalProducer { (observer, disposable) in
["foo", "bar", "zap", "bin", "fizz"].forEach { userName in
print("Sending Username: \(userName)")
observer.sendNext(userName)
}
}
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SIGNALPRODUCER - SOMETHING
var userNameProducer = SignalProducer { (observer, disposable) in
["foo", "bar", "zap", "bin", "fizz"].forEach { userName in
print("Sending Username: \(userName)")
observer.sendNext(userName)
}
}
userNameProducer.startWithNext { userName in
print("Received Username: \(userName)")
}
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OUTPUT
Sending Username: foo
Received Username: foo
Sending Username: bar
Received Username: bar
Sending Username: zap
Received Username: zap
Sending Username: bin
Received Username: bin
Sending Username: fizz
Received Username: fizz
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SIGNALPRODUCER - SIGNALPRODUCER͔ΒSIGNALPRODUCER࡞
Δ
var userNameProducer = SignalProducer { (observer, disposable) in
["foo", "bar", "zap", "bin", "fizz"].forEach { userName in
print("Sending Username: \(userName)")
observer.sendNext(userName)
}
}
userNameProducer.startWithNext { userName in
print("Received Username: \(userName)")
}
let zCounterSignal = userNameProducer.map { $0.containsString("z") }
zCounterSignal.startWithNext {
if $0 {
print("Contains z!")
} else {
print("No z here.")
}
}
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OUTPUT
No z here.
No z here.
Contains z!
No z here.
Contains z!
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RAC4.0ͷAPIมߋ
> Based on Swift 2.0
> RACSignal͕ͳ͘ͳΓ·ͨ͠ (This is a lie.)
> RAC3.0͔ΒRACSignal (HOT, COLD) ͕ Signal,
SignalProducerʹมߋ
> Global Functions Protocol Extensions
> |>(Pipe-Left)ී௨ͷ.(Dot Operator)ʹมߋ
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·ͱΊ
> RAC4͍͍FRPϥΠϒϥϦͱͯ͠ઃܭ͕ྑ͍
> ίϛϡχςΟ͕ϔϧγʔͰਐԽૣ͍͚
Ͳɺ·ͩϨΨγʔίʔυ͕͍ͬͯΔͷ
Ͱ'5/5'Λ্͛ΒΕͳ͍Ͱ͢
> Cocoa֦ுศར͚ͩͲɺϥΠϒϥϦΛං
େԽ͍ͤͯ͞Δ