#[non_exhaustive]pub enum ExpirationState {
Disabled,
Enabled,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against ExpirationState, it is important to ensure
your code is forward-compatible. That is, if a match arm handles a case for a
feature that is supported by the service but has not been represented as an enum
variant in a current version of SDK, your code should continue to work when you
upgrade SDK to a future version in which the enum does include a variant for that
feature.
Here is an example of how you can make a match expression forward-compatible:
# let expirationstate = unimplemented!();
match expirationstate {
ExpirationState::Disabled => { /* ... */ },
ExpirationState::Enabled => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}The above code demonstrates that when expirationstate represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ExpirationState::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
ExpirationState::Unknown(UnknownVariantValue("NewFeature".to_owned()))
and calling as_str on it yields "NewFeature".
This match expression is forward-compatible when executed with a newer
version of SDK where the variant ExpirationState::NewFeature is defined.
Specifically, when expirationstate represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on ExpirationState::NewFeature also yielding "NewFeature".
Explicitly matching on the Unknown variant should
be avoided for two reasons:
- The inner data
UnknownVariantValueis opaque, and no further information can be extracted. - It might inadvertently shadow other intended match arms.
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
Disabled
Enabled
Unknown(UnknownVariantValue)
Unknown. See the docs on this enum for the correct way to handle unknown variants.Unknown contains new variants that have been added since this code was generated.
Implementations§
Source§impl ExpirationState
impl ExpirationState
Sourcepub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
pub fn try_parse(value: &str) -> Result<Self, UnknownVariantError>
Parses the enum value while disallowing unknown variants.
Unknown variants will result in an error.
Trait Implementations§
Source§impl AsRef<str> for ExpirationState
impl AsRef<str> for ExpirationState
Source§impl Clone for ExpirationState
impl Clone for ExpirationState
Source§fn clone(&self) -> ExpirationState
fn clone(&self) -> ExpirationState
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moreSource§impl Debug for ExpirationState
impl Debug for ExpirationState
Source§impl Display for ExpirationState
impl Display for ExpirationState
Source§impl From<&str> for ExpirationState
impl From<&str> for ExpirationState
Source§impl FromStr for ExpirationState
impl FromStr for ExpirationState
Source§impl Hash for ExpirationState
impl Hash for ExpirationState
Source§impl Ord for ExpirationState
impl Ord for ExpirationState
Source§fn cmp(&self, other: &ExpirationState) -> Ordering
fn cmp(&self, other: &ExpirationState) -> Ordering
1.21.0 · Source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
Source§impl PartialEq for ExpirationState
impl PartialEq for ExpirationState
Source§impl PartialOrd for ExpirationState
impl PartialOrd for ExpirationState
impl Eq for ExpirationState
impl StructuralPartialEq for ExpirationState
Auto Trait Implementations§
impl Freeze for ExpirationState
impl RefUnwindSafe for ExpirationState
impl Send for ExpirationState
impl Sync for ExpirationState
impl Unpin for ExpirationState
impl UnwindSafe for ExpirationState
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
Source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
Source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.Source§impl<T> Instrument for T
impl<T> Instrument for T
Source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
Source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
Source§impl<T> IntoEither for T
impl<T> IntoEither for T
Source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left is true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read moreSource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self into a Left variant of Either<Self, Self>
if into_left(&self) returns true.
Converts self into a Right variant of Either<Self, Self>
otherwise. Read more