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