#[non_exhaustive]pub enum AllowMessages {
All,
None,
Unknown(UnknownVariantValue),
}Expand description
When writing a match expression against AllowMessages, 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 allowmessages = unimplemented!();
match allowmessages {
AllowMessages::All => { /* ... */ },
AllowMessages::None => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when allowmessages represents
NewFeature, the execution path will lead to the second last match arm,
even though the enum does not contain a variant AllowMessages::NewFeature
in the current version of SDK. The reason is that the variable other,
created by the @ operator, is bound to
AllowMessages::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 AllowMessages::NewFeature is defined.
Specifically, when allowmessages represents NewFeature,
the execution path will hit the second last match arm as before by virtue of
calling as_str on AllowMessages::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
All
None
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 AllowMessages
impl AllowMessages
source§impl AllowMessages
impl AllowMessages
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 AllowMessages
impl AsRef<str> for AllowMessages
source§impl Clone for AllowMessages
impl Clone for AllowMessages
source§fn clone(&self) -> AllowMessages
fn clone(&self) -> AllowMessages
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source. Read moresource§impl Debug for AllowMessages
impl Debug for AllowMessages
source§impl From<&str> for AllowMessages
impl From<&str> for AllowMessages
source§impl FromStr for AllowMessages
impl FromStr for AllowMessages
source§impl Hash for AllowMessages
impl Hash for AllowMessages
source§impl Ord for AllowMessages
impl Ord for AllowMessages
source§fn cmp(&self, other: &AllowMessages) -> Ordering
fn cmp(&self, other: &AllowMessages) -> 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 AllowMessages
impl PartialEq for AllowMessages
source§fn eq(&self, other: &AllowMessages) -> bool
fn eq(&self, other: &AllowMessages) -> bool
self and other values to be equal, and is used
by ==.source§impl PartialOrd for AllowMessages
impl PartialOrd for AllowMessages
source§fn partial_cmp(&self, other: &AllowMessages) -> Option<Ordering>
fn partial_cmp(&self, other: &AllowMessages) -> 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 AllowMessages
impl StructuralEq for AllowMessages
impl StructuralPartialEq for AllowMessages
Auto Trait Implementations§
impl RefUnwindSafe for AllowMessages
impl Send for AllowMessages
impl Sync for AllowMessages
impl Unpin for AllowMessages
impl UnwindSafe for AllowMessages
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
§impl<Q, K> Comparable<K> for Q
impl<Q, K> Comparable<K> for Q
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
§impl<Q, K> Equivalent<K> for Q
impl<Q, K> Equivalent<K> for Q
§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key and return true if they are equal.