use std::future::Future; use std::sync::Arc; use std::task::{Context, Poll, Wake}; use std::thread::{self, Thread};
/// A waker that wakes up the current thread when called.
struct ThreadWaker(Thread);
impl Wake for ThreadWaker {fn wake(self: Arc<Self>) {self.0.unpark();}}
/// Run a future to completion on the current thread.
fn block_on<T>(fut: impl Future<Output = T>) -> T {
// Pin the future so it can be polled.
let mut fut = Box::pin(fut);
// Create a new context to be passed to the future.
let t = thread::current();let waker = Arc::new(ThreadWaker(t)).into();
let mut cx = Context::from_waker(&waker);
// Run the future to completion.
loop {match fut.as_mut().poll(&mut cx) {
Poll::Ready(res) => return res, Poll::Pending => thread::park(),
}
}
}
async fn edition() -> i32 {2018}
pub fn main(){println!("{}", block_on(edition()));}