control-flow-app

Control flow API alternative for if else with when-then-else Examples

private func loadConfiguration() {
    let isProduction = true

    when(isProduction)
        .then { print("production configuration is loaded") }
        .else { print("debug configuration is loaded") }
}

@discardableResult
private func findState() -> Int {
    let isProduction = false
    let state = when(isProduction)
        .then(1)
        .else(0)
    print("state=", state)
    return state
}


@discardableResult
private func displayAgeInstructions() -> String {
    let age = 40
    let banner = when(age > 40)
        .then("Consider buying AUDI RS6 Avant!")
        .else("Stick to Ford Focus!")
    print("banner=", banner)
    return banner
}

private func displayMatchingCars() {
    let age = 40
    when(age)
        .greater(than: 50) { print("Bentley") }
        .greaterThan(orEqual: 40) { print("AUDI RS6") } /// prints
        .equal(to: 40) { print("AUDI A3") } /// prints
        .equal(to: 20) { print("Ford Fiesta") }
        .lower(than: 10) { print("Toy Car") }
        .lowerThan(orEqual: 10) { print("No Car") }
        .else { print("Cyber Truck") }

    let newAge = 0
    when(newAge)
        .greater(than: 50) { print("Bentley") }
        .greaterThan(orEqual: 40) { print("AUDI RS6") }
        .equal(to: 40) { print("AUDI A3") }
        .equal(to: 20) { print("Ford Fiesta") }
        .in(0...5) { print("Remote Controlled Cars") }
        .not(in: 0...5) { print("Metal Cars") }
        .found(in: [0, 1]) { print("Electric Bike!") }
        .in(0..<5) { print("Bike") }
        .not(in: 0..<5) { print("Trolley") }
        .else { print("Cyber Truck!!!") }
}


private func setUpVideoState() {
    enum VideoState {
        case pause
        case play
        case stop
    }
    let state = VideoState.pause
    let value: Int = when(state)
        .case(.pause) { 5 }
        .case(.pause) { 1 }
        .case(.play) { 2 }
        .case(.stop) { 3 }
        .else { -1 }

    print("value is ", value)
}