Struct IterableFoldFn 

pub struct IterableFoldFn<F>(pub F);

A wrapper that converts a function returning an iterable into a FoldFunc.

IterableFoldFn(f) where f: S -> impl IntoIterator<Item = A> implements FoldFunc<S, A> by iterating over f(s) and folding with the monoid. This avoids allocating an intermediate Vec<A> when the source is already an iterable structure (e.g., a Vec<A>) or when a lazy iterator suffices.

Type Parameters

• F: The type of the inner function.

Tuple Fields

0: F

Trait Implementations

impl<F: Clone> Clone for IterableFoldFn<F>

Type Parameters

• F: The type of the inner function.

fn clone(&self) -> Self

Type Signature

forall F. &IterableFoldFn F -> IterableFoldFn F

Returns

A new Fold instance that is a copy of the original.

Examples

use fp_library::types::optics::IterableFoldFn;

let f = IterableFoldFn(|v: Vec<i32>| v);
let cloned = f.clone();
assert_eq!(cloned.0(vec![1, 2]), vec![1, 2]);

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

Performs copy-assignment from source.

impl<'a, S, A, I, F> FoldFunc<'a, S, A> for IterableFoldFn<F>

where F: Fn(S) -> I, I: IntoIterator<Item = A>,

Type Parameters

• 'a: The lifetime of the function.
• S: The source type of the structure.
• A: The type of the focuses.
• I: The iterable type returned by the function.
• F: The type of the inner function.

fn apply<R: Monoid>(&self, f: impl Fn(A) -> R + 'a, s: S) -> R

Type Signature

forall S A I R. (Monoid R, IntoIterator I) => (&IterableFoldFn S A I (S -> I), A -> R, S) -> R

Type Parameters

• R: The monoid type to fold into.

Parameters

• &self: The fold instance.
• f: The mapping function.
• s: The structure to fold.

Returns

The combined monoid value.

Examples

use fp_library::{
	brands::optics::*,
	classes::monoid::Monoid,
	types::optics::{
		FoldFunc,
		IterableFoldFn,
	},
};

let fold = IterableFoldFn(|v: Vec<i32>| v);
let result = fold.apply::<String>(|x| x.to_string(), vec![1, 2, 3]);
assert_eq!(result, "123".to_string());