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