Struct Endofunction 

pub struct Endofunction<'a, FnBrand: ClonableFn, A>(pub <FnBrand as ClonableFn>::Of<'a, A, A>);

A wrapper for endofunctions (functions from a set to the same set) that enables monoidal operations.

Endofunction a represents a function a -> a.

It exists to provide a monoid instance where:

• The binary operation append is function composition.
• The identity element empty is the identity function.

The wrapped function can be accessed directly via the .0 field.

Tuple Fields

0: <FnBrand as ClonableFn>::Of<'a, A, A>

Implementations

impl<'a, FnBrand: ClonableFn, A> Endofunction<'a, FnBrand, A>

pub fn new(f: <FnBrand as ClonableFn>::Of<'a, A, A>) -> Self

Creates a new Endofunction.

This function wraps a function a -> a in an Endofunction struct.

Type Signature

forall a. (a -> a) -> Endofunction a

Type Parameters

• FnBrand: The brand of the function (e.g., RcFnBrand).
• A: The input and output type of the function.

Parameters

• f: The function to wrap.

Returns

A new Endofunction.

Examples

use fp_library::types::endofunction::Endofunction;
use fp_library::brands::RcFnBrand;
use fp_library::classes::clonable_fn::ClonableFn;

let f = Endofunction::<RcFnBrand, _>::new(<RcFnBrand as ClonableFn>::new(|x: i32| x * 2));
assert_eq!(f.0(5), 10);

Trait Implementations

impl<'a, FnBrand: ClonableFn, A> Clone for Endofunction<'a, FnBrand, A>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, FnBrand: ClonableFn, A> Debug for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: Debug,

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

Formats the value using the given formatter.

impl<'a, FnBrand: ClonableFn, A> Hash for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: Hash,

fn hash<H: Hasher>(&self, state: &mut H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'a, FnBrand: 'a + ClonableFn, A: 'a> Monoid for Endofunction<'a, FnBrand, A>

fn empty() -> Self

The identity element.

This method returns the identity endofunction, which wraps the identity function.

Type Signature

forall a. Monoid (Endofunction a) => () -> Endofunction a

Returns

The identity endofunction.

Examples

use fp_library::types::endofunction::Endofunction;
use fp_library::brands::RcFnBrand;
use fp_library::classes::monoid::Monoid;

let id = Endofunction::<RcFnBrand, i32>::empty();
assert_eq!(id.0(5), 5);

impl<'a, FnBrand: ClonableFn, A> Ord for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: Ord,

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<'a, FnBrand: ClonableFn, A> PartialEq for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: PartialEq,

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a, FnBrand: ClonableFn, A> PartialOrd for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: PartialOrd,

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'a, FnBrand: 'a + ClonableFn, A: 'a> Semigroup for Endofunction<'a, FnBrand, A>

fn append(a: Self, b: Self) -> Self

The result of combining the two values using the semigroup operation.

This method composes two endofunctions into a single endofunction. Note that Endofunction composition is reversed relative to standard function composition: append(f, g) results in f . g (read as “f after g”), meaning g is applied first, then f.

Type Signature

forall a. Semigroup (Endofunction a) => (Endofunction a, Endofunction a) -> Endofunction a

Parameters

• a: The second function to apply (the outer function).
• b: The first function to apply (the inner function).

Returns

The composed function a . b.

Examples

use fp_library::types::endofunction::Endofunction;
use fp_library::brands::RcFnBrand;
use fp_library::classes::clonable_fn::ClonableFn;
use fp_library::classes::semigroup::Semigroup;

let f = Endofunction::<RcFnBrand, _>::new(<RcFnBrand as ClonableFn>::new(|x: i32| x * 2));
let g = Endofunction::<RcFnBrand, _>::new(<RcFnBrand as ClonableFn>::new(|x: i32| x + 1));

// f(g(x)) = (x + 1) * 2
let h = Semigroup::append(f, g);
assert_eq!(h.0(5), 12);

impl<'a, FnBrand: ClonableFn, A> Eq for Endofunction<'a, FnBrand, A>

where <FnBrand as ClonableFn>::Of<'a, A, A>: Eq,