Enum aws_sdk_s3::types::ExpressionType
source · #[non_exhaustive]pub enum ExpressionType {
Sql,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ExpressionType
, 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 expressiontype = unimplemented!();
match expressiontype {
ExpressionType::Sql => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when expressiontype
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ExpressionType::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ExpressionType::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 ExpressionType::NewFeature
is defined.
Specifically, when expressiontype
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ExpressionType::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
Sql
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 ExpressionType
impl ExpressionType
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 ExpressionType
impl AsRef<str> for ExpressionType
source§impl Clone for ExpressionType
impl Clone for ExpressionType
source§fn clone(&self) -> ExpressionType
fn clone(&self) -> ExpressionType
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ExpressionType
impl Debug for ExpressionType
source§impl Display for ExpressionType
impl Display for ExpressionType
source§impl From<&str> for ExpressionType
impl From<&str> for ExpressionType
source§impl FromStr for ExpressionType
impl FromStr for ExpressionType
source§impl Hash for ExpressionType
impl Hash for ExpressionType
source§impl Ord for ExpressionType
impl Ord for ExpressionType
source§fn cmp(&self, other: &ExpressionType) -> Ordering
fn cmp(&self, other: &ExpressionType) -> 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 ExpressionType
impl PartialEq for ExpressionType
source§impl PartialOrd for ExpressionType
impl PartialOrd for ExpressionType
impl Eq for ExpressionType
impl StructuralPartialEq for ExpressionType
Auto Trait Implementations§
impl Freeze for ExpressionType
impl RefUnwindSafe for ExpressionType
impl Send for ExpressionType
impl Sync for ExpressionType
impl Unpin for ExpressionType
impl UnwindSafe for ExpressionType
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§default unsafe fn clone_to_uninit(&self, dst: *mut T)
default unsafe fn clone_to_uninit(&self, dst: *mut T)
clone_to_uninit
)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§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.