#[non_exhaustive]
pub enum SupportedStorageEnum {
Ebs,
S3,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against SupportedStorageEnum
, 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 supportedstorageenum = unimplemented!();
match supportedstorageenum {
SupportedStorageEnum::Ebs => { /* ... */ },
SupportedStorageEnum::S3 => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when supportedstorageenum
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant SupportedStorageEnum::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
SupportedStorageEnum::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 SupportedStorageEnum::NewFeature
is defined.
Specifically, when supportedstorageenum
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on SupportedStorageEnum::NewFeature
also yielding "NewFeature"
.
Explicitly matching on the Unknown
variant should
be avoided for two reasons:
- The inner data
UnknownVariantValue
is 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
Ebs
S3
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for SupportedStorageEnum
impl AsRef<str> for SupportedStorageEnum
source§impl Clone for SupportedStorageEnum
impl Clone for SupportedStorageEnum
source§fn clone(&self) -> SupportedStorageEnum
fn clone(&self) -> SupportedStorageEnum
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for SupportedStorageEnum
impl Debug for SupportedStorageEnum
source§impl From<&str> for SupportedStorageEnum
impl From<&str> for SupportedStorageEnum
source§impl FromStr for SupportedStorageEnum
impl FromStr for SupportedStorageEnum
source§impl Hash for SupportedStorageEnum
impl Hash for SupportedStorageEnum
source§impl Ord for SupportedStorageEnum
impl Ord for SupportedStorageEnum
source§fn cmp(&self, other: &SupportedStorageEnum) -> Ordering
fn cmp(&self, other: &SupportedStorageEnum) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<SupportedStorageEnum> for SupportedStorageEnum
impl PartialEq<SupportedStorageEnum> for SupportedStorageEnum
source§fn eq(&self, other: &SupportedStorageEnum) -> bool
fn eq(&self, other: &SupportedStorageEnum) -> bool
source§impl PartialOrd<SupportedStorageEnum> for SupportedStorageEnum
impl PartialOrd<SupportedStorageEnum> for SupportedStorageEnum
source§fn partial_cmp(&self, other: &SupportedStorageEnum) -> Option<Ordering>
fn partial_cmp(&self, other: &SupportedStorageEnum) -> Option<Ordering>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
self
and other
) and is used by the <=
operator. Read moreimpl Eq for SupportedStorageEnum
impl StructuralEq for SupportedStorageEnum
impl StructuralPartialEq for SupportedStorageEnum
Auto Trait Implementations§
impl RefUnwindSafe for SupportedStorageEnum
impl Send for SupportedStorageEnum
impl Sync for SupportedStorageEnum
impl Unpin for SupportedStorageEnum
impl UnwindSafe for SupportedStorageEnum
Blanket Implementations§
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.