Trait enum_map::Enum

pub trait Enum: Sized {
    type Array<V>: Array;

    // Required methods
    fn from_usize(value: usize) -> Self;
    fn into_usize(self) -> usize;
}

Enum mapping type.

This trait is implemented by #[derive(Enum)].

This trait is also implemented by bool and u8. While u8 is strictly speaking not an actual enum, there are good reasons to consider it like one, as array of u8 keys is a relatively common pattern.

Required Associated Types

type Array<V>: Array

Representation of an enum.

For an enum with four elements it looks like this.

type Array<V> = [V; 4];

Required Methods

fn from_usize(value: usize) -> Self

Takes an usize, and returns an element matching into_usize function.

fn into_usize(self) -> usize

Returns an unique identifier for a value within range of 0..Array::LENGTH.

Object Safety

This trait is not object safe.

Implementations on Foreign Types

impl Enum for Ordering

type Array<V> = [V; 3]

fn from_usize(value: usize) -> Self

fn into_usize(self) -> usize

impl Enum for Infallible

type Array<V> = [V; 0]

fn from_usize(_: usize) -> Self

fn into_usize(self) -> usize

impl Enum for bool

type Array<V> = [V; 2]

fn from_usize(value: usize) -> Self

fn into_usize(self) -> usize

impl Enum for u8

type Array<V> = [V; 256]

fn from_usize(value: usize) -> Self

fn into_usize(self) -> usize

impl Enum for ()

type Array<V> = [V; 1]

fn from_usize(value: usize) -> Self

fn into_usize(self) -> usize

Implementors