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