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