#[non_exhaustive]
pub enum CompressionTypeValue {
Gzip,
None,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against CompressionTypeValue
, 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 compressiontypevalue = unimplemented!();
match compressiontypevalue {
CompressionTypeValue::Gzip => { /* ... */ },
CompressionTypeValue::None => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when compressiontypevalue
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant CompressionTypeValue::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
CompressionTypeValue::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 CompressionTypeValue::NewFeature
is defined.
Specifically, when compressiontypevalue
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on CompressionTypeValue::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
Gzip
None
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for CompressionTypeValue
impl AsRef<str> for CompressionTypeValue
source§impl Clone for CompressionTypeValue
impl Clone for CompressionTypeValue
source§fn clone(&self) -> CompressionTypeValue
fn clone(&self) -> CompressionTypeValue
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for CompressionTypeValue
impl Debug for CompressionTypeValue
source§impl From<&str> for CompressionTypeValue
impl From<&str> for CompressionTypeValue
source§impl FromStr for CompressionTypeValue
impl FromStr for CompressionTypeValue
source§impl Hash for CompressionTypeValue
impl Hash for CompressionTypeValue
source§impl Ord for CompressionTypeValue
impl Ord for CompressionTypeValue
source§fn cmp(&self, other: &CompressionTypeValue) -> Ordering
fn cmp(&self, other: &CompressionTypeValue) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<CompressionTypeValue> for CompressionTypeValue
impl PartialEq<CompressionTypeValue> for CompressionTypeValue
source§fn eq(&self, other: &CompressionTypeValue) -> bool
fn eq(&self, other: &CompressionTypeValue) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<CompressionTypeValue> for CompressionTypeValue
impl PartialOrd<CompressionTypeValue> for CompressionTypeValue
source§fn partial_cmp(&self, other: &CompressionTypeValue) -> Option<Ordering>
fn partial_cmp(&self, other: &CompressionTypeValue) -> 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 CompressionTypeValue
impl StructuralEq for CompressionTypeValue
impl StructuralPartialEq for CompressionTypeValue
Auto Trait Implementations§
impl RefUnwindSafe for CompressionTypeValue
impl Send for CompressionTypeValue
impl Sync for CompressionTypeValue
impl Unpin for CompressionTypeValue
impl UnwindSafe for CompressionTypeValue
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.