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