Trait SplitFirst 

pub trait SplitFirst
where
    Self: Sized,
{
    type First;

    // Required method
    fn split_first(self) -> Option<(Self::First, Self)>;

    // Provided method
    unsafe fn split_first_unchecked(self) -> (Self::First, Self) { ... }
}

Split out the first element of a collection.

Required Associated Types

type First

Required Methods

fn split_first(self) -> Option<(Self::First, Self)>

Provided Methods

unsafe fn split_first_unchecked(self) -> (Self::First, Self)

Split off the first element without checking if one exists.

Safety

The collection must have at least one element otherwise this function may cause undefined behaviour if implemented.

The default implementation simply calls unwrap on split_first.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<'a, T> SplitFirst for &'a [T]

type First = &'a T

fn split_first(self) -> Option<(Self::First, Self)>

unsafe fn split_first_unchecked(self) -> (Self::First, Self)

impl<'a, T> SplitFirst for &'a mut [T]

type First = &'a mut T

fn split_first(self) -> Option<(Self::First, Self)>

unsafe fn split_first_unchecked(self) -> (Self::First, Self)

impl<S, T> SplitFirst for (S, T)

where S: SplitFirst, T: SplitFirst,

type First = (<S as SplitFirst>::First, <T as SplitFirst>::First)

fn split_first(self) -> Option<(Self::First, Self)>

Implementors

impl<S, I> SplitFirst for Subset<S, I>

where I: SplitFirst + AsRef<[usize]>, <I as SplitFirst>::First: Borrow<usize>, S: Set + SplitAt + SplitFirst,

This impl enables Subsets of Subsets

type First = <S as SplitFirst>::First

impl<S, O> SplitFirst for Chunked<S, O>

where S: Viewed + Set + SplitAt, O: GetOffset + SplitOffsetsAt,

type First = S

impl<S: SplitPrefix<N> + Set, N: Copy> SplitFirst for UniChunked<S, U<N>>

type First = <S as SplitPrefix<N>>::Prefix