Trait num_traits::identities::One

[+] Show declaration

pub trait One: Sized + Mul<Self, Output = Self> {
    fn one() -> Self;

    fn is_one(&self) -> bool
    where
        Self: PartialEq,
    { ... }
}

[−] Expand description

Defines a multiplicative identity element for Self.

Required Methods

fn one() -> Self[−]

Returns the multiplicative identity element of Self, 1.

Laws

a * 1 = a       ∀ a ∈ Self
1 * a = a       ∀ a ∈ Self

Purity

This function should return the same result at all times regardless of external mutable state, for example values stored in TLS or in static muts.

Provided Methods

fn is_one(&self) -> bool where
    Self: PartialEq, [−]

Returns true if self is equal to the multiplicative identity.

For performance reasons, it's best to implement this manually. After a semver bump, this method will be required, and the where Self: PartialEq bound will be removed.

Implementations on Foreign Types

impl One for usize

[−] Expand description

fn one() -> usize

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for u8

[−] Expand description

fn one() -> u8

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for u16

[−] Expand description

fn one() -> u16

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for u32

[−] Expand description

fn one() -> u32

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for u64

[−] Expand description

fn one() -> u64

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for u128

[−] Expand description

fn one() -> u128

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for isize

[−] Expand description

fn one() -> isize

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for i8

[−] Expand description

fn one() -> i8

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for i16

[−] Expand description

fn one() -> i16

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for i32

[−] Expand description

fn one() -> i32

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for i64

[−] Expand description

fn one() -> i64

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for i128

[−] Expand description

fn one() -> i128

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for f32

[−] Expand description

fn one() -> f32

fn is_one(&self) -> bool where     Self: PartialEq,

impl One for f64

[−] Expand description

fn one() -> f64

fn is_one(&self) -> bool where     Self: PartialEq,

impl<T: One> One for Wrapping<T> where     Wrapping<T>: Mul<Output = Wrapping<T>>,

[−] Expand description

fn one() -> Self

fn is_one(&self) -> bool where     Self: PartialEq,

Implementors