Add documentation/example to Extend impl

This commit is contained in:
Sebastian Widua 2021-06-20 11:19:55 +02:00
parent 96b7d07a47
commit 7b90759733

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@ -359,12 +359,30 @@ impl Extend<()> for () {
fn extend_one(&mut self, _item: ()) {}
}
#[stable(feature = "extend_for_tuple", since = "1.54.0")]
#[stable(feature = "extend_for_tuple", since = "1.55.0")]
impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB)
where
ExtendA: Extend<A>,
ExtendB: Extend<B>,
{
/// Allows to `extend` a tuple of collections that also implement `Extend`.
///
/// See also: [`Iterator::unzip`]
///
/// # Examples
/// ```
/// let mut tuple = (vec![0], vec![1]);
/// tuple.extend(vec![(2, 3), (4, 5), (6, 7)]);
/// assert_eq!(tuple.0, vec![0, 2, 4, 6]);
/// assert_eq!(tuple.1, vec![1, 3, 5, 7]);
///
/// // also allows for arbitrarily nested tuples
/// let mut nested_tuple = (vec![(1, -1)], vec![(2, -2)]);
/// nested_tuple.extend(vec![((3, -3), (4, -4)), ((5, -5), (6, -6))]);
///
/// assert_eq!(nested_tuple.0, vec![(1, -1), (3, -3), (5, -5)]);
/// assert_eq!(nested_tuple.1, vec![(2, -2), (4, -4), (6, -6)]);
/// ```
fn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T) {
let (a, b) = self;
let iter = into_iter.into_iter();