| //! The `stream_select` macro. |
| |
| #[cfg(feature = "std")] |
| #[allow(unreachable_pub)] |
| #[doc(hidden)] |
| pub use futures_macro::stream_select_internal; |
| |
| /// Combines several streams, all producing the same `Item` type, into one stream. |
| /// This is similar to `select_all` but does not require the streams to all be the same type. |
| /// It also keeps the streams inline, and does not require `Box<dyn Stream>`s to be allocated. |
| /// Streams passed to this macro must be `Unpin`. |
| /// |
| /// If multiple streams are ready, one will be pseudo randomly selected at runtime. |
| /// |
| /// # Examples |
| /// |
| /// ``` |
| /// # futures::executor::block_on(async { |
| /// use futures::{stream, StreamExt, stream_select}; |
| /// let endless_ints = |i| stream::iter(vec![i].into_iter().cycle()).fuse(); |
| /// |
| /// let mut endless_numbers = stream_select!(endless_ints(1i32), endless_ints(2), endless_ints(3)); |
| /// match endless_numbers.next().await { |
| /// Some(1) => println!("Got a 1"), |
| /// Some(2) => println!("Got a 2"), |
| /// Some(3) => println!("Got a 3"), |
| /// _ => unreachable!(), |
| /// } |
| /// # }); |
| /// ``` |
| #[cfg(feature = "std")] |
| #[macro_export] |
| macro_rules! stream_select { |
| ($($tokens:tt)*) => {{ |
| use $crate::__private as __futures_crate; |
| $crate::stream_select_internal! { |
| $( $tokens )* |
| } |
| }} |
| } |