#[non_exhaustive]pub enum DisplayLanguageCode {
De,
En,
Es,
Fr,
It,
Ja,
Ko,
Pt,
Zh,
ZhTw,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against DisplayLanguageCode
, 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 displaylanguagecode = unimplemented!();
match displaylanguagecode {
DisplayLanguageCode::De => { /* ... */ },
DisplayLanguageCode::En => { /* ... */ },
DisplayLanguageCode::Es => { /* ... */ },
DisplayLanguageCode::Fr => { /* ... */ },
DisplayLanguageCode::It => { /* ... */ },
DisplayLanguageCode::Ja => { /* ... */ },
DisplayLanguageCode::Ko => { /* ... */ },
DisplayLanguageCode::Pt => { /* ... */ },
DisplayLanguageCode::Zh => { /* ... */ },
DisplayLanguageCode::ZhTw => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when displaylanguagecode
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant DisplayLanguageCode::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
DisplayLanguageCode::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 DisplayLanguageCode::NewFeature
is defined.
Specifically, when displaylanguagecode
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on DisplayLanguageCode::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
De
En
Es
Fr
It
Ja
Ko
Pt
Zh
ZhTw
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 DisplayLanguageCode
impl DisplayLanguageCode
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 DisplayLanguageCode
impl AsRef<str> for DisplayLanguageCode
source§impl Clone for DisplayLanguageCode
impl Clone for DisplayLanguageCode
source§fn clone(&self) -> DisplayLanguageCode
fn clone(&self) -> DisplayLanguageCode
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for DisplayLanguageCode
impl Debug for DisplayLanguageCode
source§impl Display for DisplayLanguageCode
impl Display for DisplayLanguageCode
source§impl From<&str> for DisplayLanguageCode
impl From<&str> for DisplayLanguageCode
source§impl FromStr for DisplayLanguageCode
impl FromStr for DisplayLanguageCode
source§impl Hash for DisplayLanguageCode
impl Hash for DisplayLanguageCode
source§impl Ord for DisplayLanguageCode
impl Ord for DisplayLanguageCode
source§fn cmp(&self, other: &DisplayLanguageCode) -> Ordering
fn cmp(&self, other: &DisplayLanguageCode) -> 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 DisplayLanguageCode
impl PartialEq for DisplayLanguageCode
source§fn eq(&self, other: &DisplayLanguageCode) -> bool
fn eq(&self, other: &DisplayLanguageCode) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for DisplayLanguageCode
impl PartialOrd for DisplayLanguageCode
source§fn partial_cmp(&self, other: &DisplayLanguageCode) -> Option<Ordering>
fn partial_cmp(&self, other: &DisplayLanguageCode) -> 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 DisplayLanguageCode
impl StructuralPartialEq for DisplayLanguageCode
Auto Trait Implementations§
impl Freeze for DisplayLanguageCode
impl RefUnwindSafe for DisplayLanguageCode
impl Send for DisplayLanguageCode
impl Sync for DisplayLanguageCode
impl Unpin for DisplayLanguageCode
impl UnwindSafe for DisplayLanguageCode
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> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.source§impl<T> Instrument for T
impl<T> Instrument for T
source§fn instrument(self, span: Span) -> Instrumented<Self>
fn instrument(self, span: Span) -> Instrumented<Self>
source§fn in_current_span(self) -> Instrumented<Self>
fn in_current_span(self) -> Instrumented<Self>
source§impl<T> IntoEither for T
impl<T> IntoEither for T
source§fn into_either(self, into_left: bool) -> Either<Self, Self>
fn into_either(self, into_left: bool) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left
is true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read moresource§fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
self
into a Left
variant of Either<Self, Self>
if into_left(&self)
returns true
.
Converts self
into a Right
variant of Either<Self, Self>
otherwise. Read more