Struct Endofunction 

pub struct Endofunction<'a, ClonableFnBrand: ClonableFn, A: 'a>(pub ApplyFn<'a, ClonableFnBrand, 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.

Examples

use fp_library::{
    brands::{EndofunctionBrand, RcFnBrand},
    functions::{append, empty},
    classes::ClonableFn,
    types::Endofunction,
};
use std::rc::Rc;

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

// Compose functions (f after g)
let fg = append::<RcFnBrand, EndofunctionBrand<RcFnBrand, i32>>(f)(g);
assert_eq!(fg.0(3), 8); // double(increment(3)) = 8

// Identity element
let id = empty::<EndofunctionBrand<RcFnBrand, i32>>();
assert_eq!(id.0(42), 42);

Tuple Fields

0: ApplyFn<'a, ClonableFnBrand, A, A>

Implementations

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

pub fn new(a: ApplyFn<'a, ClonableFnBrand, A, A>) -> Self

Trait Implementations

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

where ApplyFn<'a, ClonableFnBrand, A, A>: Debug,

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

Formats the value using the given formatter.

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

where ApplyFn<'a, ClonableFnBrand, 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, ClonableFnBrand: 'a + ClonableFn, A> Monoid<'a> for Endofunction<'a, ClonableFnBrand, A>

fn empty() -> Self

Examples

use fp_library::{
    brands::{EndofunctionBrand, RcFnBrand},
    functions::empty,
    types::Endofunction,
};

assert_eq!(empty::<EndofunctionBrand<RcFnBrand, i32>>().0(5), 5);
assert_eq!(empty::<EndofunctionBrand<RcFnBrand, String>>().0("test".to_string()), "test");

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

where ApplyFn<'a, ClonableFnBrand, 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, ClonableFnBrand: ClonableFn, A> PartialEq for Endofunction<'a, ClonableFnBrand, A>

where ApplyFn<'a, ClonableFnBrand, 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, ClonableFnBrand: ClonableFn, A> PartialOrd for Endofunction<'a, ClonableFnBrand, A>

where ApplyFn<'a, ClonableFnBrand, 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<'b, ClonableFnBrand: 'b + ClonableFn, A> Semigroup<'b> for Endofunction<'b, ClonableFnBrand, A>

fn append<'a, CFB: 'a + 'b + ClonableFn>( a: Self, ) -> ApplyFn<'a, CFB, Self, Self>

where Self: Sized, 'b: 'a,

Examples

use fp_library::{
    brands::{EndofunctionBrand, RcFnBrand},
    functions::append,
    classes::ClonableFn,
    types::Endofunction,
};
use std::rc::Rc;

let double = <RcFnBrand as ClonableFn>::new(|x: i32| x * 2);
let increment = <RcFnBrand as ClonableFn>::new(|x: i32| x + 1);

assert_eq!(
    (append::<RcFnBrand, EndofunctionBrand<RcFnBrand, i32>>(Endofunction(double))(Endofunction(increment.clone()))).0(3),
    8
);
assert_eq!(
    (append::<RcFnBrand, EndofunctionBrand<RcFnBrand, i32>>(Endofunction(increment.clone()))(Endofunction(increment))).0(3),
    5
);

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

where ApplyFn<'a, ClonableFnBrand, A, A>: Eq,