A macro for declaring async lazily evaluated statics in Rust.
dependencies
async_static = "0.1"
once_cell = "1"
# Only used in the current example
tokio = { version = "1", features = ["full"] }src
use async_static::async_static;
use tokio::time::sleep;
async fn get_num() -> i32 {
println!("hello world");
sleep(Duration::from_millis(100)).await;
123
}
async_static! {
static ref FOO:i32 = get_num().await;
}
/// run print
/// ```
/// hello world
/// The result of the first call: 123
/// The result of the second call: 123
/// ```
#[tokio::test]
async fn test() {
// The first call, print hello world
let n = FOO.await;
println!("The result of the first call: {}", n);
// The second call, nothing print
let n = FOO.await;
println!("The result of the second call: {}", n);
}Licensed under either of
at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions