use crate::stream::Stream;

/// Conversion into a `Stream`.
///
/// By implementing `IntoIterator` for a type, you define how it will be
/// converted to an iterator. This is common for types which describe a
/// collection of some kind.
///
/// [`from_stream`]: #tymethod.from_stream
/// [`Stream`]: trait.Stream.html
/// [`collect`]: trait.Stream.html#method.collect
///
/// See also: [`FromStream`].
///
/// [`FromStream`]: trait.FromStream.html
#[cfg(feature = "unstable")]
#[cfg_attr(feature = "docs", doc(cfg(unstable)))]
pub trait IntoStream {
    /// The type of the elements being iterated over.
    type Item;

    /// Which kind of stream are we turning this into?
    type IntoStream: Stream<Item = Self::Item>;

    /// Creates a stream from a value.
    fn into_stream(self) -> Self::IntoStream;
}

impl<I: Stream> IntoStream for I {
    type Item = I::Item;
    type IntoStream = I;

    #[inline]
    fn into_stream(self) -> I {
        self
    }
}