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