Struct CountFold 

pub struct CountFold<L> { /* private fields */ }

A zero-allocation count fold.

Implementations

impl<L> CountFold<L>

pub fn new() -> Self

Create a new count fold.

Trait Implementations

impl<L: Clone> Clone for CountFold<L>

fn clone(&self) -> CountFold<L>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<L: Debug> Debug for CountFold<L>

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

Formats the value using the given formatter.

impl<L> Default for CountFold<L>

fn default() -> Self

Returns the “default value” for a type.

impl<L> Fold<L, usize> for CountFold<L>

fn initial(&self, _context: &FoldContext) -> usize

Get the initial state before any entries are processed.

fn step(&self, state: usize, _entry: &L, _context: &FoldContext) -> usize

Process a single entry and return the new state.

fn finalize(&self, state: S, _context: &FoldContext) -> S

Finalize the state after all entries are processed.

fn derive<'a, I>(&self, entries: I, context: &FoldContext) -> FoldOutcome<S>

where Self: Sized, I: IntoIterator<Item = &'a L>, L: 'a,

Derive state from an iterator of entries.

fn derive_filtered<'a, I, F>( &self, entries: I, context: &FoldContext, filter: F, ) -> FoldOutcome<S>

where Self: Sized, I: IntoIterator<Item = &'a L>, L: 'a, F: Fn(&L) -> bool,

Derive state with a filter.

impl<L> TryFold<L, usize> for CountFold<L>

fn try_step( &self, state: usize, entry: &L, context: &FoldContext, ) -> Result<usize, FoldFailure>

Process a single entry and return an error instead of panicking.

impl<L: Copy> Copy for CountFold<L>