#[non_exhaustive]pub enum VehicleMiddlewareProtocol {
Ros2,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against VehicleMiddlewareProtocol
, 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 vehiclemiddlewareprotocol = unimplemented!();
match vehiclemiddlewareprotocol {
VehicleMiddlewareProtocol::Ros2 => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when vehiclemiddlewareprotocol
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant VehicleMiddlewareProtocol::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
VehicleMiddlewareProtocol::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 VehicleMiddlewareProtocol::NewFeature
is defined.
Specifically, when vehiclemiddlewareprotocol
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on VehicleMiddlewareProtocol::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
Ros2
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 VehicleMiddlewareProtocol
impl VehicleMiddlewareProtocol
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 VehicleMiddlewareProtocol
impl AsRef<str> for VehicleMiddlewareProtocol
source§impl Clone for VehicleMiddlewareProtocol
impl Clone for VehicleMiddlewareProtocol
source§fn clone(&self) -> VehicleMiddlewareProtocol
fn clone(&self) -> VehicleMiddlewareProtocol
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for VehicleMiddlewareProtocol
impl Debug for VehicleMiddlewareProtocol
source§impl From<&str> for VehicleMiddlewareProtocol
impl From<&str> for VehicleMiddlewareProtocol
source§impl FromStr for VehicleMiddlewareProtocol
impl FromStr for VehicleMiddlewareProtocol
source§impl Hash for VehicleMiddlewareProtocol
impl Hash for VehicleMiddlewareProtocol
source§impl Ord for VehicleMiddlewareProtocol
impl Ord for VehicleMiddlewareProtocol
source§fn cmp(&self, other: &VehicleMiddlewareProtocol) -> Ordering
fn cmp(&self, other: &VehicleMiddlewareProtocol) -> 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 VehicleMiddlewareProtocol
impl PartialEq for VehicleMiddlewareProtocol
source§fn eq(&self, other: &VehicleMiddlewareProtocol) -> bool
fn eq(&self, other: &VehicleMiddlewareProtocol) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for VehicleMiddlewareProtocol
impl PartialOrd for VehicleMiddlewareProtocol
source§fn partial_cmp(&self, other: &VehicleMiddlewareProtocol) -> Option<Ordering>
fn partial_cmp(&self, other: &VehicleMiddlewareProtocol) -> 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 VehicleMiddlewareProtocol
impl StructuralEq for VehicleMiddlewareProtocol
impl StructuralPartialEq for VehicleMiddlewareProtocol
Auto Trait Implementations§
impl RefUnwindSafe for VehicleMiddlewareProtocol
impl Send for VehicleMiddlewareProtocol
impl Sync for VehicleMiddlewareProtocol
impl Unpin for VehicleMiddlewareProtocol
impl UnwindSafe for VehicleMiddlewareProtocol
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
§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,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§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,
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.