#[non_exhaustive]
pub enum DashDisplayFragmentNumber {
Always,
Never,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against DashDisplayFragmentNumber
, 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 dashdisplayfragmentnumber = unimplemented!();
match dashdisplayfragmentnumber {
DashDisplayFragmentNumber::Always => { /* ... */ },
DashDisplayFragmentNumber::Never => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when dashdisplayfragmentnumber
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant DashDisplayFragmentNumber::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
DashDisplayFragmentNumber::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 DashDisplayFragmentNumber::NewFeature
is defined.
Specifically, when dashdisplayfragmentnumber
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on DashDisplayFragmentNumber::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
Always
Never
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for DashDisplayFragmentNumber
impl AsRef<str> for DashDisplayFragmentNumber
source§impl Clone for DashDisplayFragmentNumber
impl Clone for DashDisplayFragmentNumber
source§fn clone(&self) -> DashDisplayFragmentNumber
fn clone(&self) -> DashDisplayFragmentNumber
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for DashDisplayFragmentNumber
impl Debug for DashDisplayFragmentNumber
source§impl From<&str> for DashDisplayFragmentNumber
impl From<&str> for DashDisplayFragmentNumber
source§impl FromStr for DashDisplayFragmentNumber
impl FromStr for DashDisplayFragmentNumber
source§impl Hash for DashDisplayFragmentNumber
impl Hash for DashDisplayFragmentNumber
source§impl Ord for DashDisplayFragmentNumber
impl Ord for DashDisplayFragmentNumber
source§fn cmp(&self, other: &DashDisplayFragmentNumber) -> Ordering
fn cmp(&self, other: &DashDisplayFragmentNumber) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq<DashDisplayFragmentNumber> for DashDisplayFragmentNumber
impl PartialEq<DashDisplayFragmentNumber> for DashDisplayFragmentNumber
source§fn eq(&self, other: &DashDisplayFragmentNumber) -> bool
fn eq(&self, other: &DashDisplayFragmentNumber) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<DashDisplayFragmentNumber> for DashDisplayFragmentNumber
impl PartialOrd<DashDisplayFragmentNumber> for DashDisplayFragmentNumber
source§fn partial_cmp(&self, other: &DashDisplayFragmentNumber) -> Option<Ordering>
fn partial_cmp(&self, other: &DashDisplayFragmentNumber) -> 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 DashDisplayFragmentNumber
impl StructuralEq for DashDisplayFragmentNumber
impl StructuralPartialEq for DashDisplayFragmentNumber
Auto Trait Implementations§
impl RefUnwindSafe for DashDisplayFragmentNumber
impl Send for DashDisplayFragmentNumber
impl Sync for DashDisplayFragmentNumber
impl Unpin for DashDisplayFragmentNumber
impl UnwindSafe for DashDisplayFragmentNumber
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.