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