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