Winter maybe-async

This crate contains a maybe_async proc macro that abstracts away sync/async. It is heavily based on maybe-async.

The maybe_async macro will generate a synchronous or asynchronous version of the trait it is marking. To generate the asynchronous version, enable the async feature on the crate. If the async feature is off, the synchronous version will be generated. For example,

#[maybe_async]
trait ExampleTrait {
    async fn say_hello(&self) {
        let hello = self.get_hello().await;

        println!("{}", hello);
    }

    async fn get_hello(&self) -> String {
        "hello".into()
    }
}

// Generate code when `async` feature is turned ON
#[async_trait]
trait ExampleTrait {
    async fn say_hello(&self) {
        let hello = self.get_hello().await;

        println!("{}", hello);
    }

    async fn get_hello(&self) -> String {
        "hello".into()
    }
}

// Generate code when `async` feature is turned OFF
trait ExampleTrait {
    fn say_hello(&self) {
        let hello = self.get_hello();

        println!("{}", hello);
    }

    fn get_hello(&self) -> String {
        "hello".into()
    }
}

where #[async_trait] is the proc macro provided by the async-trait crate. Notice how #[maybe_async] took care of removing the .await in the synchronous version of say_hello().

#[maybe_async] can also mark impl blocks in a similar manner. For example,

struct ExampleStruct;

#[maybe_async]
impl ExampleTrait for ExampleStruct {
    async fn say_hello(&self) {
        println!("hello!");
    }
}

// Generate code when `async` feature is turned ON
#[async_trait]
impl ExampleTrait for ExampleStruct {
    async fn say_hello(&self) {
        println!("hello!");
    }
}

// Generate code when `async` feature is turned OFF
impl ExampleTrait for ExampleStruct {
    fn say_hello(&self) {
        println!("hello!");
    }
}

Finally, #[maybe_async] can be used on fn items, which works in an analogous way to the previous examples.

#[maybe_async]
async fn say_hello() {
    // ...
}

License

This project is MIT licensed.