Enum Token 

pub enum Token<T, S> {
    Known(T),
    Unknown(S),
}

A token which may be a statically known value of type T or else an unknown value of type S.

The principal use of this type is to allow finite enums to be extended with arbitrary values, most commonly some unknown string which is permissible but statically unknowable.

Variants

Known(T)

A statically known value.

Unknown(S)

An unknown or vendor-defined value.

Implementations

impl<T, S> Token<T, S>

pub fn try_from_str<'a>( s: &'a str, ) -> Result<Self, <&'a str as TryInto<S>>::Error>

where T: FromStr, &'a str: TryInto<S>,

Like FromStr, but uses a fallible conversion for the unknown variant.

pub fn map_unknown<U>(self, f: impl FnOnce(S) -> U) -> Token<T, U>

Maps the unknown value of a Token, leaving known values unchanged.

Trait Implementations

impl<T: Clone, S: Clone> Clone for Token<T, S>

fn clone(&self) -> Token<T, S>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T: Debug, S: Debug> Debug for Token<T, S>

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

Formats the value using the given formatter.

impl<T: Default, S> Default for Token<T, S>

fn default() -> Self

Returns the “default value” for a type.

impl<T: Display, S: Display> Display for Token<T, S>

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

Formats the value using the given formatter.

impl<T, S> FromStr for Token<T, S>

where T: FromStr, for<'a> &'a str: Into<S>,

type Err = Infallible

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl<T: Hash, S: Hash> Hash for Token<T, S>

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<T: Ord, S: Ord> Ord for Token<T, S>

fn cmp(&self, other: &Token<T, S>) -> 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<T: PartialEq, S: PartialEq> PartialEq for Token<T, S>

fn eq(&self, other: &Token<T, S>) -> 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<T: PartialOrd, S: PartialOrd> PartialOrd for Token<T, S>

fn partial_cmp(&self, other: &Token<T, S>) -> 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<T: Copy, S: Copy> Copy for Token<T, S>

impl<T: Eq, S: Eq> Eq for Token<T, S>

impl<T, S> StructuralPartialEq for Token<T, S>