Macro pasts::poll

macro_rules! poll {
    ($f:expr) => { ... };
    ($($f:expr),* $(,)?) => { ... };
}

Create a future that polls multiple futures concurrently.

Takes an array of types that implement Future and Unpin. If you're dealing with futures that don't implement Unpin, you can use the task!() macro to make it implement Unpin. The resulting type will be the same as other futures created with task!().

Examples

Await on The Fastest Future

poll!() will always poll the first future in the array first.

use pasts::prelude::*;

async fn async_main() {
    task!(let hello = async { "Hello" });
    task!(let world = async { "World!"});
    // Hello is ready, so returns with index and result.
    assert_eq!((0, "Hello"), poll!(hello, world).await);
}

exec!(async_main());

Await the Outputs of Two Futures Concurrently

use pasts::prelude::*;

async fn async_main() {
    task!(let hello = async { (0, "Hello") });
    task!(let world = async { (1, "World!") });
    let mut task_queue = vec![hello, world];
    while !task_queue.is_empty() {
        let (index, output) = poll!(task_queue).await;
        task_queue.remove(index);
        match output {
            (0, a) => assert_eq!(a, "Hello"),
            (1, a) => assert_eq!(a, "World!"),
            _ => unreachable!(),
        }
    }
}

exec!(async_main());