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Reverse ordering of split_{first,last}_chunk to be (preceding, last)

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These methods currently return `(last_chunk, preceding_slice)`, which matches
the existing `split_x` methods that remove one item.

Change these to instead return `(preceding_slice, last_chunk)` which matches
string split methods, should be more intuitive, and will allow for consistency
with methods that split more items.
This commit is contained in:
Trevor Gross 2023-11-03 19:59:26 -05:00
parent 9c20ddd956
commit 55020c6f2f
1 changed files with 7 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

14
library/core/src/slice/mod.rs
View file

@ -456,15 +456,15 @@ impl<T> [T] {
///
/// let x = &[0, 1, 2];
///
/// if let Some((last, elements)) = x.split_last_chunk::<2>() {
/// assert_eq!(last, &[1, 2]);
/// if let Some((elements, last)) = x.split_last_chunk::<2>() {
/// assert_eq!(elements, &[0]);
/// assert_eq!(last, &[1, 2]);
/// }
/// ```
#[unstable(feature = "slice_first_last_chunk", issue = "111774")]
#[rustc_const_unstable(feature = "slice_first_last_chunk", issue = "111774")]
#[inline]
pub const fn split_last_chunk<const N: usize>(&self) -> Option<(&[T; N], &[T])> {
pub const fn split_last_chunk<const N: usize>(&self) -> Option<(&[T], &[T; N])> {
if self.len() < N {
None
} else {
@ -473,7 +473,7 @@ impl<T> [T] {
// SAFETY: We explicitly check for the correct number of elements,
// and do not let the references outlive the slice.
Some((unsafe { &*(last.as_ptr() as *const [T; N]) }, init))
Some((init, unsafe { &*(last.as_ptr() as *const [T; N]) }))
}
}
@ -486,7 +486,7 @@ impl<T> [T] {
///
/// let x = &mut [0, 1, 2];
///
/// if let Some((last, elements)) = x.split_last_chunk_mut::<2>() {
/// if let Some((elements, last)) = x.split_last_chunk_mut::<2>() {
/// last[0] = 3;
/// last[1] = 4;
/// elements[0] = 5;
@ -498,7 +498,7 @@ impl<T> [T] {
#[inline]
pub const fn split_last_chunk_mut<const N: usize>(
&mut self,
) -> Option<(&mut [T; N], &mut [T])> {
) -> Option<(&mut [T], &mut [T; N])> {
if self.len() < N {
None
} else {
@ -508,7 +508,7 @@ impl<T> [T] {
// SAFETY: We explicitly check for the correct number of elements,
// do not let the reference outlive the slice,
// and enforce exclusive mutability of the chunk by the split.
Some((unsafe { &mut *(last.as_mut_ptr() as *mut [T; N]) }, init))
Some((init, unsafe { &mut *(last.as_mut_ptr() as *mut [T; N]) }))
}
}