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