Enum aws_smithy_types::tristate::TriState

pub enum TriState<T> {
    Unset,
    Disabled,
    Set(T),
}

Utility for tracking set vs. unset vs explicitly disabled

If someone explicitly disables something, we don’t need to warn them that it may be missing. This enum impls From/Into Option<T> for ease of use.

Variants

Unset

This variant represents something that was unset by default

Disabled

This variant represents something that was intentionally unset

Set(T)

This variant represents something that was intentionally set

Implementations

impl<T> TriState<T>

pub fn or_unset(t: Option<T>) -> Self

Create a TriState, returning Unset when None is passed

pub fn is_unset(&self) -> bool

Return true if this TriState is Unset

pub fn or(self, other: TriState<T>) -> TriState<T>

Returns the tristate if it contains a set value or is disabled, otherwise returns other

Examples

let disabled_timeout: TriState<Duration> = TriState::Disabled;
let timeout: TriState<Duration> = TriState::Set(Duration::from_secs(1));
assert_eq!(timeout.or(disabled_timeout), TriState::Set(Duration::from_secs(1)));

let disabled_timeout: TriState<Duration> = TriState::Disabled;
let timeout: TriState<Duration> = TriState::Set(Duration::from_secs(2));
assert_eq!(disabled_timeout.or(timeout), TriState::Disabled);

let unset_timeout: TriState<Duration> = TriState::Unset;
let timeout: TriState<Duration> = TriState::Set(Duration::from_secs(3));
assert_eq!(unset_timeout.or(timeout), TriState::Set(Duration::from_secs(3)));

pub fn map<U, F>(self, f: F) -> TriState<U> where
    F: FnOnce(T) -> U, 

Maps a TriState<T> to TriState<U> by applying a function to a contained value.

Trait Implementations

impl<T: Clone> Clone for TriState<T>

fn clone(&self) -> TriState<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for TriState<T>

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

Formats the value using the given formatter.

impl<T> Default for TriState<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> From<Option<T>> for TriState<T>

fn from(t: Option<T>) -> Self

Converts to this type from the input type.

impl<T> From<TriState<T>> for Option<T>

fn from(t: TriState<T>) -> Self

Converts to this type from the input type.

impl<T: PartialEq> PartialEq<TriState<T>> for TriState<T>

fn eq(&self, other: &TriState<T>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &TriState<T>) -> bool

This method tests for !=.

impl<T: Eq> Eq for TriState<T>

impl<T> StructuralEq for TriState<T>

impl<T> StructuralPartialEq for TriState<T>