#[non_exhaustive]pub enum GuideVisibility {
External,
Internal,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against GuideVisibility
, 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 guidevisibility = unimplemented!();
match guidevisibility {
GuideVisibility::External => { /* ... */ },
GuideVisibility::Internal => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when guidevisibility
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant GuideVisibility::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
GuideVisibility::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 GuideVisibility::NewFeature
is defined.
Specifically, when guidevisibility
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on GuideVisibility::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
External
Internal
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
Source§impl AsRef<str> for GuideVisibility
impl AsRef<str> for GuideVisibility
Source§impl Clone for GuideVisibility
impl Clone for GuideVisibility
Source§fn clone(&self) -> GuideVisibility
fn clone(&self) -> GuideVisibility
1.0.0 · Source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moreSource§impl Debug for GuideVisibility
impl Debug for GuideVisibility
Source§impl From<&str> for GuideVisibility
impl From<&str> for GuideVisibility
Source§impl FromStr for GuideVisibility
impl FromStr for GuideVisibility
Source§impl Hash for GuideVisibility
impl Hash for GuideVisibility
Source§impl Ord for GuideVisibility
impl Ord for GuideVisibility
Source§fn cmp(&self, other: &GuideVisibility) -> Ordering
fn cmp(&self, other: &GuideVisibility) -> 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 GuideVisibility
impl PartialEq for GuideVisibility
Source§impl PartialOrd for GuideVisibility
impl PartialOrd for GuideVisibility
impl Eq for GuideVisibility
impl StructuralPartialEq for GuideVisibility
Auto Trait Implementations§
impl Freeze for GuideVisibility
impl RefUnwindSafe for GuideVisibility
impl Send for GuideVisibility
impl Sync for GuideVisibility
impl Unpin for GuideVisibility
impl UnwindSafe for GuideVisibility
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<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
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impl<Q, K> Equivalent<K> for Q
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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