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Feature gate: #![feature(iter_next_chunk)]

This is a tracking issue for the .next_chunk() and .next_chunk_back() method on iterators which allows you to advance the iterator N elements and return an array [T; N]

Public API

use core::array;

trait Iterator {
    type Item;
    
    fn next_chunk<const N: usize>(&mut self) -> Result<[Self::Item; N], array::IntoIter<Self::Item, N>>
    where
        Self: Sized;
}

trait DoubleEndedIterator {
    fn next_chunk_back<const N: usize>(&mut self) -> Result<[Self::Item; N], array::IntoIter<Self::Item, N>>
    where
        Self: Sized;
}

Steps / History

• Implementation:
  • Add Iterator::next_chunk #93700
  • Optimized vec::IntoIter::next_chunk impl #98553
  • Optimize slice_iter.copied().next_chunk() #103166
  • optimize next_chunk impls for Filter and FilterMap #111781
  • fix Drop items getting leaked in Filter::next_chunk #126879
  • Implement DoubleEndedIterator::next_chunk_back #156737
• Final comment period (FCP)
• Stabilization PR

Unresolved Questions

• Naming: other options include next_array() or next_array_chunk().
• How should we handle N = 0?