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