#[non_exhaustive]
pub enum FormatConfigKey {
JpegQuality,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against FormatConfigKey
, 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 formatconfigkey = unimplemented!();
match formatconfigkey {
FormatConfigKey::JpegQuality => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when formatconfigkey
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant FormatConfigKey::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
FormatConfigKey::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 FormatConfigKey::NewFeature
is defined.
Specifically, when formatconfigkey
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on FormatConfigKey::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
JpegQuality
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl AsRef<str> for FormatConfigKey
impl AsRef<str> for FormatConfigKey
source§impl Clone for FormatConfigKey
impl Clone for FormatConfigKey
source§fn clone(&self) -> FormatConfigKey
fn clone(&self) -> FormatConfigKey
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for FormatConfigKey
impl Debug for FormatConfigKey
source§impl From<&str> for FormatConfigKey
impl From<&str> for FormatConfigKey
source§impl FromStr for FormatConfigKey
impl FromStr for FormatConfigKey
source§impl Hash for FormatConfigKey
impl Hash for FormatConfigKey
source§impl Ord for FormatConfigKey
impl Ord for FormatConfigKey
source§fn cmp(&self, other: &FormatConfigKey) -> Ordering
fn cmp(&self, other: &FormatConfigKey) -> Ordering
1.21.0 · source§fn max(self, other: Self) -> Selfwhere
Self: Sized,
fn max(self, other: Self) -> Selfwhere Self: Sized,
source§impl PartialEq<FormatConfigKey> for FormatConfigKey
impl PartialEq<FormatConfigKey> for FormatConfigKey
source§fn eq(&self, other: &FormatConfigKey) -> bool
fn eq(&self, other: &FormatConfigKey) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd<FormatConfigKey> for FormatConfigKey
impl PartialOrd<FormatConfigKey> for FormatConfigKey
source§fn partial_cmp(&self, other: &FormatConfigKey) -> Option<Ordering>
fn partial_cmp(&self, other: &FormatConfigKey) -> 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 FormatConfigKey
impl StructuralEq for FormatConfigKey
impl StructuralPartialEq for FormatConfigKey
Auto Trait Implementations§
impl RefUnwindSafe for FormatConfigKey
impl Send for FormatConfigKey
impl Sync for FormatConfigKey
impl Unpin for FormatConfigKey
impl UnwindSafe for FormatConfigKey
Blanket Implementations§
source§impl<Q, K> Equivalent<K> for Qwhere
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Qwhere Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,
source§fn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
key
and return true
if they are equal.