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