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