7 releases
0.2.0 | Jun 27, 2022 |
---|---|
0.1.5 | Dec 6, 2021 |
#1207 in Asynchronous
73 downloads per month
20KB
360 lines
A set of traits and proc-macros involved in making and using generators
to create AsyncIterator
s, Future
s and Iterator
s
Asynchronous example
// a couple required nightly features
#![feature(generators, generator_trait, never_type, into_future, async_iterator)]
use jenner::generator;
use std::async_iter::AsyncIterator;
use std::time::{Instant, Duration};
/// Creates a stream that yields u32s that countdown from 5 to 0.
/// Waiting 0.2s between each (1s total)
#[generator]
#[yields(u32)]
async fn countdown() {
yield 5;
for i in (0..5).rev() {
tokio::time::sleep(Duration::from_millis(200)).await;
yield i;
}
}
/// Iterates over the provided stream, printing the value and
/// pushing it to a vec that is returned
#[generator]
async fn collect(input: impl AsyncIterator<Item = u32>) -> Vec<u32> {
let mut v = vec![];
for i in input {
println!("{:?}", i);
v.push(i)
}.await; // special syntax to consume a stream
v
}
#[tokio::main]
async fn main() {
let start = Instant::now();
// countdown() is a valid stream
// collect(...) is a valid future
let v = collect(countdown()).await;
assert_eq!(v, vec![5, 4, 3, 2, 1, 0]);
assert!(start.elapsed() > Duration::from_millis(200 * 5));
}
Synchronous example
#![feature(generators)]
use jenner::generator;
#[generator]
#[yields(usize)]
fn fibonacii() {
use std::mem;
let mut a = 0;
let mut b = 1;
loop {
yield a;
mem::swap(&mut a, &mut b);
b += a;
}
}
fn main() {
// fibonacii() is a valid `Iterator<Item = usize>`
let v: Vec<_> = fibonacii().take(10).collect();
assert_eq!(v, vec![0, 1, 1, 2, 3, 5, 8, 13, 21, 34]);
}
Dependencies
~1.5MB
~40K SLoC