# 🐷 Koryto 🐷
[](https://crates.io/crates/koryto)
[](https://docs.rs/koryto)
[](https://github.com/darthdeus/koryto/actions)
[](https://github.com/darthdeus/koryto/blob/main/LICENSE)
> Pronounced like _corrito_, which is pronounced as if you combined _coroutine_ and _burrito_, because everyone knows coroutines are [burritos](https://blog.plover.com/prog/burritos.html) in the category of endofunctors.
Game loop focused async executor for all your coroutine needs. Inspired by [macroquad's experimental coroutines](https://docs.rs/macroquad/latest/macroquad/experimental/coroutines/), [the cosync crate](https://docs.rs/cosync/latest/cosync/), [Unity's amazing coroutines](https://docs.unity3d.com/ScriptReference/MonoBehaviour.StartCoroutine.html), and lastly [Godot's coroutines](https://docs.godotengine.org/en/stable/tutorials/scripting/gdscript/gdscript_basics.html#awaiting-for-signals-or-coroutines) which for a while [weren't true burritos](https://github.com/godotengine/godot/issues/24311).
> Koryto in Czech means trough, which is the thingy pigs eat from.
Koryto is single threaded and simple. The executor context `Koryto` expects to be polled every frame with the game's _delta time_.
## Example
```rust
// Create a new instance of the executor
let mut ko = Koryto::new();
// Shared state the coroutine sets
let val = Rc::new(RefCell::new(3));
let val_inner = val.clone();
// Start a new coroutine
ko.start(async move {
wait_seconds(0.5).await;
*val_inner.borrow_mut() = 9
});
// Delta time obtained from the game loop
let dt = 0.2;
// Poll coroutines as part of the game loop
ko.poll_coroutines(dt);
assert_eq!(*val.borrow(), 3);
ko.poll_coroutines(dt);
assert_eq!(*val.borrow(), 3);
// At this point 0.5 seconds have passed and we observe the coroutine be
// resumed and set the value.
ko.poll_coroutines(dt);
assert_eq!(*val.borrow(), 9);
ko.poll_coroutines(dt);
assert_eq!(*val.borrow(), 9);
```
## FAQ
### Is this stable?
No.
### Why not just use `cosync` when this does exactly the same thing?
While [`cosync`](https://docs.rs/cosync/latest/cosync/) does work its API is a little more flexible than feels
convenient for games. [Macroquad's
coroutines](https://docs.rs/macroquad/latest/macroquad/experimental/coroutines/index.html)
are more closely aligned with the philosophy of this crate. If you like
`cosync`, keep using it!
One benefit of `koryto` over `cosync` is that it does not assume coroutines are `Sync`.
## License
`koryto` is dual licensed:
* MIT License ([LICENSE-MIT](LICENSE-MIT) or [http://opensource.org/licenses/MIT](http://opensource.org/licenses/MIT))
* Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or [http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0))