Why there is no subscription() in Sandbox ?

[Zaplae]

could just :

    fn subscription(&self) -> Subscription<T::Message> {
        T::subscription(self)
    }

in impl Application for T; T:Sandbox

and

    fn subscription(&self) -> Subscription<T::Message> {
        Subscription::none()
    }

in Sandbox

[Zaplae]

In example/arc, we impl Application but not Sandbox, because we need subscription():

impl Application for Arc {
    type Executor = executor::Default;
    type Message = Message;
    type Theme = Theme;
    type Flags = ();

    fn new(_flags: ()) -> (Self, Command<Message>) {
        (
            Arc {
                start: Instant::now(),
                cache: Default::default(),
            },
            Command::none(),
        )
    }

    fn title(&self) -> String {
        String::from("Arc - Iced")
    }

    fn update(&mut self, _: Message) -> Command<Message> {
        self.cache.clear();

        Command::none()
    }

    fn view(&self) -> Element<Message> {
        Canvas::new(self)
            .width(Length::Fill)
            .height(Length::Fill)
            .into()
    }

    fn theme(&self) -> Theme {
        Theme::Dark
    }

    fn subscription(&self) -> Subscription<Message> {
        iced::time::every(std::time::Duration::from_millis(10))
            .map(|_| Message::Tick)
    }
}

could we use sandbox to reduce it?

[matidfk]

I think Sandbox is meant to be a simple setup for simple apps/demos/examples so if you need to use subscriptions you should use Application

[Zaplae]

yeah, it is a simple trait for example/demo, so subscription is more should to be added.

[13r0ck]

Elm doesnt have a subscription in sandbox, so it is this way for historical reasons. I makes sense though, If an app has a subscription. Then it is no longer "Sandbox"ed.