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