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