1 //! The `stream_select` macro.
2 
3 #[allow(unreachable_pub)]
4 #[doc(hidden)]
5 pub use futures_macro::stream_select_internal;
6 
7 #[allow(clippy::too_long_first_doc_paragraph)]
8 /// Combines several streams, all producing the same `Item` type, into one stream.
9 /// This is similar to `select_all` but does not require the streams to all be the same type.
10 /// It also keeps the streams inline, and does not require `Box<dyn Stream>`s to be allocated.
11 /// Streams passed to this macro must be `Unpin`.
12 ///
13 /// If multiple streams are ready, one will be pseudo randomly selected at runtime.
14 ///
15 /// # Examples
16 ///
17 /// ```
18 /// # futures::executor::block_on(async {
19 /// use futures::{stream, StreamExt, stream_select};
20 /// let endless_ints = |i| stream::iter(vec![i].into_iter().cycle()).fuse();
21 ///
22 /// let mut endless_numbers = stream_select!(endless_ints(1i32), endless_ints(2), endless_ints(3));
23 /// match endless_numbers.next().await {
24 ///     Some(1) => println!("Got a 1"),
25 ///     Some(2) => println!("Got a 2"),
26 ///     Some(3) => println!("Got a 3"),
27 ///     _ => unreachable!(),
28 /// }
29 /// # });
30 /// ```
31 #[macro_export]
32 macro_rules! stream_select {
33     ($($tokens:tt)*) => {{
34         use $crate::__private as __futures_crate;
35         $crate::stream_select_internal! {
36             $( $tokens )*
37         }
38     }}
39 }
40