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