NOTE: This repository has been discontinued in favor of Actomaton.
RxAutomaton
RxSwift port of ReactiveAutomaton (State Machine).
Terminology
Whenever the word "signal" or "(signal) producer" appears (derived from ReactiveCocoa), they mean "hot-observable" and "cold-observable".
Example
(Demo app is bundled in the project)
To make a state transition diagram like above with additional effects, follow these steps:
// 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<State, Input>.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<Input>.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!
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`.
// ๐จ๐ฝ < But wait, there's more!
// Let's send `Input.forceLogout` immediately after `State.loggingIn`.
send(Input.forceLogout) // ๐ฅ๐ฃ๐ฅ
expect(automaton.state.value) == .loggingOut // logging out...
// `forcelogoutOKProducer` will automatically send `Input.logoutOK` later
// and transit to `State.loggedOut`.