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74 lines
2.3 KiB
Rust
74 lines
2.3 KiB
Rust
use core::pin::Pin;
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use core::future::Future;
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use crate::stream::IntoStream;
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/// Extends a collection with the contents of a stream.
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///
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/// Streams produce a series of values asynchronously, and collections can also be thought of as a
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/// series of values. The `Extend` trait bridges this gap, allowing you to extend a collection
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/// asynchronously by including the contents of that stream. When extending a collection with an
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/// already existing key, that entry is updated or, in the case of collections that permit multiple
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/// entries with equal keys, that entry is inserted.
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///
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/// ## Examples
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///
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/// ```
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/// # async_std::task::block_on(async {
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/// #
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/// use async_std::prelude::*;
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/// use async_std::stream;
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///
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/// let mut v: Vec<usize> = vec![1, 2];
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/// let s = stream::repeat(3usize).take(3);
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/// stream::Extend::extend(&mut v, s).await;
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///
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/// assert_eq!(v, vec![1, 2, 3, 3, 3]);
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/// #
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/// # })
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/// ```
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#[cfg(feature = "unstable")]
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#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
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pub trait Extend<A> {
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/// Extends a collection with the contents of a stream.
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fn extend<'a, T: IntoStream<Item = A> + 'a>(
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&'a mut self,
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stream: T,
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) -> Pin<Box<dyn Future<Output = ()> + 'a>>;
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}
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/// Extends a collection with the contents of a stream.
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///
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/// Streams produce a series of values asynchronously, and collections can also be thought of as a
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/// series of values. The [`Extend`] trait bridges this gap, allowing you to extend a collection
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/// asynchronously by including the contents of that stream. When extending a collection with an
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/// already existing key, that entry is updated or, in the case of collections that permit multiple
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/// entries with equal keys, that entry is inserted.
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///
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/// [`Extend`]: trait.Extend.html
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///
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/// ## Examples
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///
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/// ```
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/// # async_std::task::block_on(async {
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/// #
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/// use async_std::prelude::*;
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/// use async_std::stream;
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///
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/// let mut v: Vec<usize> = vec![1, 2];
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/// let s = stream::repeat(3usize).take(3);
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/// stream::extend(&mut v, s).await;
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///
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/// assert_eq!(v, vec![1, 2, 3, 3, 3]);
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/// #
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/// # })
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/// ```
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#[cfg(feature = "unstable")]
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#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
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pub async fn extend<'a, C, T, S>(collection: &mut C, stream: S)
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where
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C: Extend<T>,
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S: IntoStream<Item = T> + 'a,
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{
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Extend::extend(collection, stream).await
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}
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