redux.swift

// Swift 2

protocol ActionType { }

struct InitialAction: ActionType { }

class Store<State> {
    var state: State!
    typealias Reducer = (state: State?, action: ActionType) -> State
    final let reducer: Reducer

    init(with reducer: Reducer) {
        self.reducer = reducer

        dispatch(InitialAction())
    }

    typealias Subscriber = (store: Store) -> ()
    final var subscribers = [Subscriber]()

    final func dispatch(action: ActionType) {
        self.state = reducer(state: state, action: action)
        subscribers.forEach {
            $0(store: self)
        }
    }

    final func subscribe(with subscriber: Subscriber) {
        subscribers.append(subscriber)
        subscriber(store: self)
    }
}