#[non_exhaustive]pub enum ParquetVersionValue {
Parquet10,
Parquet20,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ParquetVersionValue
, 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 parquetversionvalue = unimplemented!();
match parquetversionvalue {
ParquetVersionValue::Parquet10 => { /* ... */ },
ParquetVersionValue::Parquet20 => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when parquetversionvalue
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ParquetVersionValue::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ParquetVersionValue::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 ParquetVersionValue::NewFeature
is defined.
Specifically, when parquetversionvalue
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ParquetVersionValue::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
Parquet10
Parquet20
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 ParquetVersionValue
impl ParquetVersionValue
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 ParquetVersionValue
impl AsRef<str> for ParquetVersionValue
source§impl Clone for ParquetVersionValue
impl Clone for ParquetVersionValue
source§fn clone(&self) -> ParquetVersionValue
fn clone(&self) -> ParquetVersionValue
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ParquetVersionValue
impl Debug for ParquetVersionValue
source§impl Display for ParquetVersionValue
impl Display for ParquetVersionValue
source§impl From<&str> for ParquetVersionValue
impl From<&str> for ParquetVersionValue
source§impl FromStr for ParquetVersionValue
impl FromStr for ParquetVersionValue
source§impl Hash for ParquetVersionValue
impl Hash for ParquetVersionValue
source§impl Ord for ParquetVersionValue
impl Ord for ParquetVersionValue
source§fn cmp(&self, other: &ParquetVersionValue) -> Ordering
fn cmp(&self, other: &ParquetVersionValue) -> 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 ParquetVersionValue
impl PartialEq for ParquetVersionValue
source§impl PartialOrd for ParquetVersionValue
impl PartialOrd for ParquetVersionValue
impl Eq for ParquetVersionValue
impl StructuralPartialEq for ParquetVersionValue
Auto Trait Implementations§
impl Freeze for ParquetVersionValue
impl RefUnwindSafe for ParquetVersionValue
impl Send for ParquetVersionValue
impl Sync for ParquetVersionValue
impl Unpin for ParquetVersionValue
impl UnwindSafe for ParquetVersionValue
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§unsafe fn clone_to_uninit(&self, dst: *mut T)
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.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