#[non_exhaustive]
pub enum CrossDatasetTypes {
AllDatasets,
SingleDataset,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against CrossDatasetTypes
, 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 crossdatasettypes = unimplemented!();
match crossdatasettypes {
CrossDatasetTypes::AllDatasets => { /* ... */ },
CrossDatasetTypes::SingleDataset => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when crossdatasettypes
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant CrossDatasetTypes::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
CrossDatasetTypes::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 CrossDatasetTypes::NewFeature
is defined.
Specifically, when crossdatasettypes
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on CrossDatasetTypes::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
AllDatasets
SingleDataset
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for CrossDatasetTypes
impl AsRef<str> for CrossDatasetTypes
source§impl Clone for CrossDatasetTypes
impl Clone for CrossDatasetTypes
source§fn clone(&self) -> CrossDatasetTypes
fn clone(&self) -> CrossDatasetTypes
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for CrossDatasetTypes
impl Debug for CrossDatasetTypes
source§impl From<&str> for CrossDatasetTypes
impl From<&str> for CrossDatasetTypes
source§impl FromStr for CrossDatasetTypes
impl FromStr for CrossDatasetTypes
source§impl Hash for CrossDatasetTypes
impl Hash for CrossDatasetTypes
source§impl Ord for CrossDatasetTypes
impl Ord for CrossDatasetTypes
source§fn cmp(&self, other: &CrossDatasetTypes) -> Ordering
fn cmp(&self, other: &CrossDatasetTypes) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere
Self: Sized,
source§impl PartialEq<CrossDatasetTypes> for CrossDatasetTypes
impl PartialEq<CrossDatasetTypes> for CrossDatasetTypes
source§fn eq(&self, other: &CrossDatasetTypes) -> bool
fn eq(&self, other: &CrossDatasetTypes) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<CrossDatasetTypes> for CrossDatasetTypes
impl PartialOrd<CrossDatasetTypes> for CrossDatasetTypes
source§fn partial_cmp(&self, other: &CrossDatasetTypes) -> Option<Ordering>
fn partial_cmp(&self, other: &CrossDatasetTypes) -> 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 CrossDatasetTypes
impl StructuralEq for CrossDatasetTypes
impl StructuralPartialEq for CrossDatasetTypes
Auto Trait Implementations§
impl RefUnwindSafe for CrossDatasetTypes
impl Send for CrossDatasetTypes
impl Sync for CrossDatasetTypes
impl Unpin for CrossDatasetTypes
impl UnwindSafe for CrossDatasetTypes
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.