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