#[non_exhaustive]pub enum DdbExportType {
Ddb,
S3,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against DdbExportType, 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 ddbexporttype = unimplemented!();
match ddbexporttype {
DdbExportType::Ddb => { /* ... */ },
DdbExportType::S3 => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}The above code demonstrates that when ddbexporttype represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant DdbExportType::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
DdbExportType::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 DdbExportType::NewFeature is defined.
Specifically, when ddbexporttype represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on DdbExportType::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
Ddb
S3
Unknown(UnknownVariantValue)
Don’t directly match on 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 DdbExportType
impl DdbExportType
Source§impl DdbExportType
impl DdbExportType
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 DdbExportType
impl AsRef<str> for DdbExportType
Source§impl Clone for DdbExportType
impl Clone for DdbExportType
Source§fn clone(&self) -> DdbExportType
fn clone(&self) -> DdbExportType
1.0.0 (const: unstable) · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moreSource§impl Debug for DdbExportType
impl Debug for DdbExportType
Source§impl Display for DdbExportType
impl Display for DdbExportType
Source§impl From<&str> for DdbExportType
impl From<&str> for DdbExportType
Source§impl FromStr for DdbExportType
impl FromStr for DdbExportType
Source§impl Hash for DdbExportType
impl Hash for DdbExportType
Source§impl Ord for DdbExportType
impl Ord for DdbExportType
Source§fn cmp(&self, other: &DdbExportType) -> Ordering
fn cmp(&self, other: &DdbExportType) -> Ordering
1.21.0 (const: unstable) · Source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
Source§impl PartialEq for DdbExportType
impl PartialEq for DdbExportType
Source§fn eq(&self, other: &DdbExportType) -> bool
fn eq(&self, other: &DdbExportType) -> bool
self and other values to be equal, and is used by ==.Source§impl PartialOrd for DdbExportType
impl PartialOrd for DdbExportType
impl Eq for DdbExportType
impl StructuralPartialEq for DdbExportType
Auto Trait Implementations§
impl Freeze for DdbExportType
impl RefUnwindSafe for DdbExportType
impl Send for DdbExportType
impl Sync for DdbExportType
impl Unpin for DdbExportType
impl UnsafeUnpin for DdbExportType
impl UnwindSafe for DdbExportType
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