unsafe trait StepByBackImpl<I> {
type Item;
// Required methods
fn spec_next_back(&mut self) -> Option<Self::Item>
where I: DoubleEndedIterator + ExactSizeIterator;
fn spec_nth_back(&mut self, n: usize) -> Option<Self::Item>
where I: DoubleEndedIterator + ExactSizeIterator;
fn spec_try_rfold<Acc, F, R>(&mut self, init: Acc, f: F) -> R
where I: DoubleEndedIterator + ExactSizeIterator,
F: FnMut(Acc, Self::Item) -> R,
R: Try<Output = Acc>;
fn spec_rfold<Acc, F>(self, init: Acc, f: F) -> Acc
where I: DoubleEndedIterator + ExactSizeIterator,
F: FnMut(Acc, Self::Item) -> Acc;
}Expand description
Specialization trait for double-ended iteration.
See also: StepByImpl
Safety
The specializations must be implemented together with StepByImpl
where applicable. I.e. if StepBy does support backwards iteration
for a given iterator and that is specialized for forward iteration then
it must also be specialized for backwards iteration.