Gesture_FRP.swift

class ReactiveShortViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let pan = UIPanGestureRecognizer()
        pan.delegate = self
        let rotate = UIRotationGestureRecognizer()
        rotate.delegate = self
        view.gestureRecognizers = [pan, rotate]
        
        let panStarted = pan.rx_event.map { $0.state == .Began }.filter { $0 }
        let panEnded = pan.rx_event.map { $0.state == .Ended }.filter { $0 }
        
        let rotateStarted = rotate.rx_event.map { $0.state == .Began }.filter { $0 }
        let rotateEnded = rotate.rx_event.map { $0.state == .Ended }.filter { $0 }
        
        // condition: when both pan and pinch started & ended
        let bothGesturesStarted = Observable.zip(panStarted, rotateStarted) { ($0 && $1) }
        
        let bothGesturesEnded = Observable.of(panEnded, rotateEnded).merge()
        
        // Action
        bothGesturesStarted.subscribeNext { _ in
            // create a timer that ticks every second, until 3 or until pan and pinch ended
            let timer = Observable<Int>
                .timer(repeatEvery: 1)
                .take(3)
                .takeUntil(bothGesturesEnded)
            
            timer.subscribe(onNext: { count in
                print("tick: \(count)")
                }, onCompleted: {
                    print("completed")
            })
        }
    }
}