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