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