Struct autofolder::DynFolder

pub struct DynFolder<Output, Item, Func> { /* private fields */ }

The DynFolder type uses a struct field for the folding function.

• Pros:
  • Folding function can use any type, builtin or otherwise.
  • Can’t be used with .collect() because instances have to be explicitly built with a folding function.
• Cons:
  • Slightly less efficient than ImplFolder due to the use of dynamic dispatch - we are effectively using a function pointer instead of a function call, after all.
  • Each instance can use a different folding function, provided as a constructor argument.

Example:

use autofolder::*;

// Create an autofolder that sums `u16` items into an `usize` output.
let mut sum = DynFolder::<usize, u16, _>::new(7, |a, b| a + b as usize);

// We can "fold-in" individual items:
sum.fold(3);

// We can then peek at the running output:
println!("Partial sum is {}", sum.as_ref());

// And still keep on folding by processing whole iterators:
sum.extend((1..=5));

// And finally consume the autofolder to get the final output value:
println!("Total sum is {}", sum.into_inner());

Implementations

impl<Output, Item, Func> DynFolder<Output, Item, Func>

pub fn new(initial: Output, func: Func) -> Selfwhere Func: Fn(Output, Item) -> Output,

Creates a new DynFolder with the provided initial value and folding function.

pub fn into_inner(self) -> Output

Returns the contained value, consuming the self value.

pub fn fold(&mut self, item: Item)where Func: Fn(Output, Item) -> Output,

Folds an individual value into self.

Trait Implementations

impl<Output, Item, Func> AsRef<Output> for DynFolder<Output, Item, Func>

fn as_ref(&self) -> &Output

Converts this type into a shared reference of the (usually inferred) input type.

impl<Output: Clone, Item: Clone, Func: Clone> Clone for DynFolder<Output, Item, Func>

fn clone(&self) -> DynFolder<Output, Item, Func>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<Output, Item, Func> Debug for DynFolder<Output, Item, Func>where Output: Debug,

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

Formats the value using the given formatter.

impl<Output, Item, Func> Extend<Item> for DynFolder<Output, Item, Func>where Func: Fn(Output, Item) -> Output,

fn extend<It: IntoIterator<Item = Item>>(&mut self, iter: It)

Extends a collection with the contents of an iterator.

fn extend_one(&mut self, item: A)

🔬This is a nightly-only experimental API. (extend_one)

Extends a collection with exactly one element.

fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (extend_one)

Reserves capacity in a collection for the given number of additional elements.

impl<Output: Copy, Item: Copy, Func: Copy> Copy for DynFolder<Output, Item, Func>