Enum aws_sdk_sagemaker::model::Direction
source · #[non_exhaustive]
pub enum Direction {
Ascendants,
Both,
Descendants,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against Direction
, 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 direction = unimplemented!();
match direction {
Direction::Ascendants => { /* ... */ },
Direction::Both => { /* ... */ },
Direction::Descendants => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when direction
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant Direction::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
Direction::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 Direction::NewFeature
is defined.
Specifically, when direction
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on Direction::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
Ascendants
Both
Descendants
Unknown(UnknownVariantValue)
Unknown
contains new variants that have been added since this code was generated.
Implementations§
Trait Implementations§
source§impl Ord for Direction
impl Ord for Direction
source§impl PartialEq<Direction> for Direction
impl PartialEq<Direction> for Direction
source§impl PartialOrd<Direction> for Direction
impl PartialOrd<Direction> for Direction
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 Direction
impl StructuralEq for Direction
impl StructuralPartialEq for Direction
Auto Trait Implementations§
impl RefUnwindSafe for Direction
impl Send for Direction
impl Sync for Direction
impl Unpin for Direction
impl UnwindSafe for Direction
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.