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