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https://github.com/inamiy/RxAutomaton

🤖 RxSwift + State Machine, inspired by Redux and Elm.
https://github.com/inamiy/RxAutomaton

automaton elm redux rxswift state-machine swift

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🤖 RxSwift + State Machine, inspired by Redux and Elm.

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README 

        
## NOTE: This repository has been discontinued in favor of [Actomaton](https://github.com/inamiy/Actomaton).



# RxAutomaton



[RxSwift](https://github.com/ReactiveX/RxSwift) port of [ReactiveAutomaton](https://github.com/inamiy/ReactiveAutomaton) (State Machine).



>

> ### Terminology

>

> Whenever the word "signal" or "(signal) producer" appears (derived from [ReactiveCocoa](https://github.com/ReactiveCocoa/ReactiveCocoa)), they mean "hot-observable" and "cold-observable".



## Example



(Demo app is bundled in the project)



![](Assets/login-diagram.png)



To make a state transition diagram like above _with additional effects_, follow these steps:



```swift

// 1. Define `State`s and `Input`s.

enum State {

    case loggedOut, loggingIn, loggedIn, loggingOut

}



enum Input {

    case login, loginOK, logout, logoutOK

    case forceLogout

}



// Additional effects (`Observable`s) while state-transitioning.

// (NOTE: Use `Observable.empty()` for no effect)

let loginOKProducer = /* show UI, setup DB, request APIs, ..., and send `Input.loginOK` */

let logoutOKProducer = /* show UI, clear cache, cancel APIs, ..., and send `Input.logoutOK` */

let forcelogoutOKProducer = /* do something more special, ..., and send `Input.logoutOK` */



let canForceLogout: State -> Bool = [.loggingIn, .loggedIn].contains



// 2. Setup state-transition mappings.

let mappings: [Automaton.EffectMapping] = [



  /*  Input      |   fromState => toState        |      Effect       */

  /* ----------------------------------------------------------------*/

    .login       | .loggedOut  => .loggingIn     | loginOKProducer,

    .loginOK     | .loggingIn  => .loggedIn      | .empty(),

    .logout      | .loggedIn   => .loggingOut    | logoutOKProducer,

    .logoutOK    | .loggingOut => .loggedOut     | .empty(),

    .forceLogout | canForceLogout => .loggingOut | forceLogoutOKProducer

]



// 3. Prepare input pipe for sending `Input` to `Automaton`.

let (inputSignal, inputObserver) = Observable.pipe()



// 4. Setup `Automaton`.

let automaton = Automaton(

    state: .loggedOut,

    input: inputSignal,

    mapping: reduce(mappings),  // combine mappings using `reduce` helper

    strategy: .latest   // NOTE: `.latest` cancels previous running effect

)



// Observe state-transition replies (`.success` or `.failure`).

automaton.replies.subscribe(next: { reply in

    print("received reply = \(reply)")

})



// Observe current state changes.

automaton.state.asObservable().subscribe(next: { state in

    print("current state = \(state)")

})

```



And let's test!



```swift

let send = inputObserver.onNext



expect(automaton.state.value) == .loggedIn    // already logged in

send(Input.logout)

expect(automaton.state.value) == .loggingOut  // logging out...

// `logoutOKProducer` will automatically send `Input.logoutOK` later

// and transit to `State.loggedOut`.



expect(automaton.state.value) == .loggedOut   // already logged out

send(Input.login)

expect(automaton.state.value) == .loggingIn   // logging in...

// `loginOKProducer` will automatically send `Input.loginOK` later

// and transit to `State.loggedIn`.



// 👨🏽 < But wait, there's more!

// Let's send `Input.forceLogout` immediately after `State.loggingIn`.



send(Input.forceLogout)                       // 💥💣💥

expect(automaton.state.value) == .loggingOut  // logging out...

// `forcelogoutOKProducer` will automatically send `Input.logoutOK` later

// and transit to `State.loggedOut`.

```



## License



[MIT](LICENSE)