Macro drying_paint::bind_event

macro_rules! bind_event {
    ( $watcher:expr => $root:ident ,
        $event:expr => $arg:ident ,
        $code:block ) => { ... };
}

An ergonomic wrapper for binding to an WatchedEvent. This is expected to be used from within a WatcherInit implementation.

use drying_paint::*;

type EventCounter = Watcher<EventCounterData>;

#[derive(Default)]
struct EventCounterData {
    counter: u32,
    add: WatchedEvent<u32>,
}

impl WatcherInit for EventCounterData {
    fn init(watcher: &mut WatcherMeta<Self>) {
        bind_event!(watcher => root, root.add => amount, {
            root.counter += amount;
        });
    }
}

fn main() {
    let mut ctx = WatchContext::new();
    ctx.with(|| {
        let mut item = EventCounter::new();
        item.data_mut().add.dispatch(7);
        WatchContext::update_current();
        assert_eq!(item.data().counter, 7);
        item.data_mut().add.dispatch(9);
        item.data_mut().add.dispatch(3);
        WatchContext::update_current();
        assert_eq!(item.data().counter, 19);
    });
}