Crate stream_future

source ·
Expand description

A Future with item yielded.

#![feature(generators)]

#[derive(Debug)]
enum Prog {
    Stage1,
    Stage2,
}

#[stream(Prog)]
async fn foo() -> Result<i32> {
    yield Prog::Stage1;
    // some works...
    yield Prog::Stage2;
    // some other works...
    Ok(0)
}

let bar = foo();
tokio::pin!(bar);
while let Some(prog) = bar.next().await {
    println!("{:?}", prog);
}
let bar = bar.await?;
assert_eq!(bar, 0);

If a lifetime is needed, specify it in the attribute:

#![feature(generators)]

enum Prog {
    Stage1,
    Stage2,
}

#[stream(Prog, lifetime = 'a)]
async fn foo<'a>(s: &'a str) {
    yield Prog::Stage1;
    println!("{}", s);
    yield Prog::Stage2;
}

foo("Hello world!").await;

There’s also a macro try_stream (usually used) to implement a stream iterates Result.

#![feature(generators)]

#[derive(Debug)]
enum Prog {
    Stage1,
    Stage2,
}

#[try_stream(Prog)]
async fn foo() -> Result<()> {
    yield Prog::Stage1;
    // some works...
    yield Prog::Stage2;
    // some other works...
    Ok(())
}

let bar = foo();
tokio::pin!(bar);
while let Some(prog) = bar.try_next().await? {
    println!("{:?}", prog);
}

Re-exports