Struct Fold 

pub struct Fold<'a, PointerBrand, S, T, A, B, F>
where
    PointerBrand: UnsizedCoercible,
    F: FoldFunc<'a, S, A>,
    S: 'a,
    T: 'a,
    A: 'a,
    B: 'a,
{
    pub fold_fn: F,
    /* private fields */
}

A polymorphic fold.

Matches PureScript’s Fold r s t a b.

Type Parameters

• 'a: The lifetime of the values.
• PointerBrand: The reference-counted pointer type.
• S: The source type of the structure.
• T: The target type of the structure.
• A: The source type of the focus.
• B: The target type of the focus.
• F: The type of the fold function.

Fields

fold_fn: F

The fold function.

Implementations

impl<'a, PointerBrand, S, T, A, B, F> Fold<'a, PointerBrand, S, T, A, B, F>

where PointerBrand: UnsizedCoercible, F: FoldFunc<'a, S, A>, S: 'a, T: 'a, A: 'a, B: 'a,

Type Parameters

• 'a: The lifetime of the values.
• PointerBrand: The reference-counted pointer type.
• S: The source type of the structure.
• T: The target type of the structure.
• A: The source type of the focus.
• B: The target type of the focus.
• F: The type of the fold function.

pub fn new(fold_fn: F) -> Self

Create a new polymorphic fold.

Type Signature

forall PointerBrand S T A B F. (UnsizedCoercible PointerBrand, FoldFunc F) => F -> Fold PointerBrand S T A B F

Parameters

• fold_fn: The fold function.

Returns

A new instance of the type.

Examples

use fp_library::{
	brands::{
		RcBrand,
		optics::*,
	},
	types::optics::{
		Fold,
		IterableFoldFn,
	},
};

let f: Fold<RcBrand, Vec<i32>, Vec<i32>, i32, i32, _> =
	Fold::new(IterableFoldFn(|v: Vec<i32>| v));
assert_eq!(f.to_vec(vec![1, 2]), vec![1, 2]);

pub fn to_vec(&self, s: S) -> Vec<A>

where A: Clone,

Collect all the focuses of the fold into a Vec.

Type Signature

forall PointerBrand S T A B F. (UnsizedCoercible PointerBrand, FoldFunc F) => (&Fold PointerBrand S T A B F, S) -> Vec A

Parameters

• &self: The fold instance.
• s: The structure to fold.

Returns

A Vec containing all the focuses.

Examples

use fp_library::{
	brands::{
		RcBrand,
		optics::*,
	},
	types::optics::{
		Fold,
		IterableFoldFn,
	},
};

let f: Fold<RcBrand, Vec<i32>, Vec<i32>, i32, i32, _> =
	Fold::new(IterableFoldFn(|v: Vec<i32>| v));
assert_eq!(f.to_vec(vec![1, 2, 3]), vec![1, 2, 3]);

Trait Implementations

impl<'a, PointerBrand, S, T, A, B, F> Clone for Fold<'a, PointerBrand, S, T, A, B, F>

where PointerBrand: UnsizedCoercible, F: FoldFunc<'a, S, A> + Clone, S: 'a, T: 'a, A: 'a, B: 'a,

Type Parameters

• 'a: The lifetime of the values.
• PointerBrand: The reference-counted pointer type.
• S: The source type of the structure.
• T: The target type of the structure.
• A: The source type of the focus.
• B: The target type of the focus.
• F: The type of the fold function.

fn clone(&self) -> Self

Type Signature

forall PointerBrand S T A B F. (UnsizedCoercible PointerBrand, FoldFunc F) => &Fold PointerBrand S T A B F -> Fold PointerBrand S T A B F

Returns

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

Examples

use fp_library::{
	brands::{
		RcBrand,
		optics::*,
	},
	types::optics::{
		Fold,
		IterableFoldFn,
	},
};

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

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

Performs copy-assignment from source.

impl<'a, PointerBrand, S, T, A, B, F> FoldOptic<'a, S, A> for Fold<'a, PointerBrand, S, T, A, B, F>

where PointerBrand: UnsizedCoercible, F: FoldFunc<'a, S, A> + Clone + 'a, S: 'a, T: 'a, A: 'a, B: 'a,

Type Parameters

• 'a: The lifetime of the values.
• PointerBrand: The reference-counted pointer type.
• S: The source type of the structure.
• T: The target type of the structure.
• A: The source type of the focus.
• B: The target type of the focus.
• F: The type of the fold function.

fn evaluate<R: 'a + Monoid + 'static, Q: UnsizedCoercible + 'static>( &self, pab: <ForgetBrand<Q, R> as Kind_266801a817966495>::Of<'a, A, A>, ) -> <ForgetBrand<Q, R> as Kind_266801a817966495>::Of<'a, S, S>

Type Signature

forall PointerBrand S T A B F R Q. (Monoid R, UnsizedCoercible Q, UnsizedCoercible PointerBrand, FoldFunc F) => (&Fold PointerBrand S T A B F, Forget Q R A A) -> Forget Q R S S

Type Parameters

• R: The monoid type.
• Q: The reference-counted pointer type for the Forget brand.

Parameters

• &self: The fold instance.
• pab: The profunctor value to transform.

Returns

The transformed profunctor value.

Examples

use fp_library::{
	brands::{
		optics::*,
		*,
	},
	classes::optics::*,
	functions::*,
	types::optics::*,
};

let f_optic: Fold<RcBrand, Vec<i32>, Vec<i32>, i32, i32, _> =
	Fold::new(IterableFoldFn(|v: Vec<i32>| v));
let f = Forget::<RcBrand, String, i32, i32>::new(|x: i32| x.to_string());
let folded: Forget<RcBrand, String, Vec<i32>, Vec<i32>> = FoldOptic::evaluate(&f_optic, f);
assert_eq!(folded.run(vec![1, 2, 3]), "123".to_string());