wishawa/enjoin

syntax-level async join enabling branching control flow and shared mutable borrow

enjoin

enjoin's async join macros operate at the syntax level. It allows you to...

break, continue, and return out of async code running in a join

for _ in 0..10 {
    enjoin::join!(
        {
            if do_thing_1().await {
                break;
            }
        },
        {
            if do_thing_2().await {
                continue;
            }
        }
    );
}

Use ? (try operator) in a join

async fn fetch_and_save_both() -> Result<(), Box<dyn Error>> {
    enjoin::join!(
        {
            let data = fetch_data_1().await?;
            save_data(data).await?;
        },
        {
            let data = fetch_data_2().await?;
            save_data(data).await?;
        }
    );
}

Share mutable borrows accross a join

... as long as the mutable borrows don't last across yield point / await point.

let mut count = 0;
enjoin::join_auto_borrow!(
    {
        loop {
            incr_signal.next().await;
            count += 1;
        }
    },
    {
        loop {
            decr_signal.next().await;
            count -= 1;
        }
    }
);

See my blog post here for motivations, working mechanism, comparison to other join macros, and more.