Enum aws_sdk_ec2::types::ProtocolValue
source · #[non_exhaustive]pub enum ProtocolValue {
Gre,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against ProtocolValue
, 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 protocolvalue = unimplemented!();
match protocolvalue {
ProtocolValue::Gre => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when protocolvalue
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant ProtocolValue::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
ProtocolValue::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 ProtocolValue::NewFeature
is defined.
Specifically, when protocolvalue
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on ProtocolValue::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
Gre
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for ProtocolValue
impl AsRef<str> for ProtocolValue
source§impl Clone for ProtocolValue
impl Clone for ProtocolValue
source§fn clone(&self) -> ProtocolValue
fn clone(&self) -> ProtocolValue
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for ProtocolValue
impl Debug for ProtocolValue
source§impl From<&str> for ProtocolValue
impl From<&str> for ProtocolValue
source§impl FromStr for ProtocolValue
impl FromStr for ProtocolValue
source§impl Hash for ProtocolValue
impl Hash for ProtocolValue
source§impl Ord for ProtocolValue
impl Ord for ProtocolValue
source§fn cmp(&self, other: &ProtocolValue) -> Ordering
fn cmp(&self, other: &ProtocolValue) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq<ProtocolValue> for ProtocolValue
impl PartialEq<ProtocolValue> for ProtocolValue
source§fn eq(&self, other: &ProtocolValue) -> bool
fn eq(&self, other: &ProtocolValue) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<ProtocolValue> for ProtocolValue
impl PartialOrd<ProtocolValue> for ProtocolValue
source§fn partial_cmp(&self, other: &ProtocolValue) -> Option<Ordering>
fn partial_cmp(&self, other: &ProtocolValue) -> 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 ProtocolValue
impl StructuralEq for ProtocolValue
impl StructuralPartialEq for ProtocolValue
Auto Trait Implementations§
impl RefUnwindSafe for ProtocolValue
impl Send for ProtocolValue
impl Sync for ProtocolValue
impl Unpin for ProtocolValue
impl UnwindSafe for ProtocolValue
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.