Struct Fuse

#[must_use = "iterators are lazy and do nothing unless consumed"]
pub struct Fuse<I> { pub(in ::iter::adapters::fuse) iter: Option<I> }

An iterator that yields None forever after the underlying iterator yields None once.

This struct is created by Iterator::fuse. See its documentation for more.

Fields

iter: Option<I>

Implementations

impl<I> Fuse<I>

const fn new(iter: I) -> Fuse<I>
fn into_inner(self) -> Option<I>

Trait Implementations

impl<I> DoubleEndedIterator for Fuse<I> where I: DoubleEndedIterator,

fn next_back(&mut self) -> Option<<I as Iterator>::Item>
fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
fn try_rfold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
fn rfold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
where
    Fold: FnMut(Acc, Self::Item) -> Acc,
fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,

impl<I> ExactSizeIterator for Fuse<I> where I: ExactSizeIterator,

fn len(&self) -> usize
fn is_empty(&self) -> bool

impl<I> FuseImpl<I> for Fuse<I> where I: FusedIterator,

fn next(&mut self) -> Option<<I as Iterator>::Item>
fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>
fn nth(&mut self, n: usize) -> Option<I::Item>
fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,
fn next_back(&mut self) -> Option<<I as Iterator>::Item>
where
    I: DoubleEndedIterator,
fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
where
    I: DoubleEndedIterator,
fn try_rfold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
    I: DoubleEndedIterator,
fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,
    I: DoubleEndedIterator,

impl<I> FuseImpl<I> for Fuse<I> where I: Iterator,

type Item = <I as Iterator>::Item;
fn next(&mut self) -> Option<<I as Iterator>::Item>
fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>
fn nth(&mut self, n: usize) -> Option<I::Item>
fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,
fn next_back(&mut self) -> Option<<I as Iterator>::Item>
where
    I: DoubleEndedIterator,
fn nth_back(&mut self, n: usize) -> Option<<I as Iterator>::Item>
where
    I: DoubleEndedIterator,
fn try_rfold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
    I: DoubleEndedIterator,
fn rfind<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,
    I: DoubleEndedIterator,

impl<I> FusedIterator for Fuse<I> where I: Iterator,

impl<I> Iterator for Fuse<I> where I: Iterator,

type Item = <I as Iterator>::Item;
fn next(&mut self) -> Option<Self::Item>
fn advance_by(&mut self, n: usize) -> Result<(), NonZero<usize>>
fn nth(&mut self, n: usize) -> Option<I::Item>
fn last(self) -> Option<Self::Item>
fn count(self) -> usize
fn size_hint(&self) -> (usize, Option<usize>)
fn try_fold<Acc, Fold, R>(&mut self, acc: Acc, fold: Fold) -> R
where
    Self: Sized,
    Fold: FnMut(Acc, Self::Item) -> R,
    R: Try<Output = Acc>,
fn fold<Acc, Fold>(self, acc: Acc, fold: Fold) -> Acc
where
    Fold: FnMut(Acc, Self::Item) -> Acc,
fn find<P>(&mut self, predicate: P) -> Option<Self::Item>
where
    P: FnMut(&Self::Item) -> bool,
unsafe fn __iterator_get_unchecked(&mut self, idx: usize) -> Self::Item
where
    Self: TrustedRandomAccessNoCoerce,

impl<I> SourceIter for Fuse<I> where I: SourceIter + TrustedFused,

type Source = <I as SourceIter>::Source;
unsafe fn as_inner(&mut self) -> &mut I::Source

impl<I> TrustedFused for Fuse<I> where I: TrustedFused,

impl<I> TrustedLen for Fuse<I> where I: TrustedLen,

impl<I> TrustedRandomAccess for Fuse<I> where I: TrustedRandomAccess,

impl<I> TrustedRandomAccessNoCoerce for Fuse<I> where I: TrustedRandomAccessNoCoerce,

const MAY_HAVE_SIDE_EFFECT: bool = I::MAY_HAVE_SIDE_EFFECT;

impl<I: Clone> Clone for Fuse<I>

fn clone(&self) -> Fuse<I>

impl<I: Debug> Debug for Fuse<I>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

impl<I: Default> Default for Fuse<I>

fn default() -> Self

Creates a Fuse iterator from the default value of I.

# use core::slice;
# use std::iter::Fuse;
let iter: Fuse<slice::Iter<'_, u8>> = Default::default();
assert_eq!(iter.len(), 0);

This is equivalent to I::default().fuse()1; e.g. if I::default() is not an empty iterator, then this will not be an empty iterator.

# use std::iter::Fuse;
#[derive(Default)]
struct Fourever;

impl Iterator for Fourever {
    type Item = u32;
    fn next(&mut self) -> Option<u32> {
        Some(4)
    }
}

let mut iter: Fuse<Fourever> = Default::default();
assert_eq!(iter.next(), Some(4));

  1. if I does not override Iterator::fuse's default implementation ↩

Auto Trait Implementations

impl<I> Freeze for Fuse<I> where Option<I>: Freeze,

impl<I> RefUnwindSafe for Fuse<I> where Option<I>: RefUnwindSafe,

impl<I> Send for Fuse<I> where Option<I>: Send,

impl<I> Sync for Fuse<I> where Option<I>: Sync,

impl<I> Unpin for Fuse<I> where Option<I>: Unpin,

impl<I> UnsafeUnpin for Fuse<I> where Option<I>: UnsafeUnpin,

impl<I> UnwindSafe for Fuse<I> where Option<I>: UnwindSafe,

Blanket Implementations

impl<I> IntoIterator for Fuse<I> where I: Iterator,

type Item = <I as Iterator>::Item;
type IntoIter = I;
fn into_iter(self) -> I

impl<T> Any for Fuse<I> where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for Fuse<I> where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for Fuse<I> where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> CloneToUninit for Fuse<I> where T: Clone,

unsafe fn clone_to_uninit(&self, dest: *mut u8)

impl<T> From<T> for Fuse<I>

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> SizeHint for Fuse<I> where T: ?Sized,

fn lower_bound(&self) -> usize
fn upper_bound(&self) -> Option<usize>

impl<T> SizedTypeProperties for Fuse<I>

impl<T, U> Into<U> for Fuse<I> where U: From<T>,

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of [From]<T> for U chooses to do.

impl<T, U> TryFrom<U> for Fuse<I> where U: Into<T>,

type Error = Infallible;
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for Fuse<I> where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error;
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>