htc_3.2.swift

struct AppState {
    var user: User
}
enum AppEvent {
    case newUserWasLoaded(User)
}
extension AppEvent {
    static func reduce(state: AppState, event: AppEvent) -> AppState {
        var state = state
        switch event {
        case .newUserWasLoaded(let user):
            state.user = user
        }
        return state
    }
}