#[non_exhaustive]pub enum TeletextPageType {
PageTypeAddlInfo,
PageTypeHearingImpairedSubtitle,
PageTypeInitial,
PageTypeProgramSchedule,
PageTypeSubtitle,
Unknown(UnknownVariantValue),
}
Expand description
When writing a match expression against TeletextPageType
, 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 teletextpagetype = unimplemented!();
match teletextpagetype {
TeletextPageType::PageTypeAddlInfo => { /* ... */ },
TeletextPageType::PageTypeHearingImpairedSubtitle => { /* ... */ },
TeletextPageType::PageTypeInitial => { /* ... */ },
TeletextPageType::PageTypeProgramSchedule => { /* ... */ },
TeletextPageType::PageTypeSubtitle => { /* ... */ },
other @ _ if other.as_str() == "NewFeature" => { /* handles a case for `NewFeature` */ },
_ => { /* ... */ },
}
The above code demonstrates that when teletextpagetype
represents
NewFeature
, the execution path will lead to the second last match arm,
even though the enum does not contain a variant TeletextPageType::NewFeature
in the current version of SDK. The reason is that the variable other
,
created by the @
operator, is bound to
TeletextPageType::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 TeletextPageType::NewFeature
is defined.
Specifically, when teletextpagetype
represents NewFeature
,
the execution path will hit the second last match arm as before by virtue of
calling as_str
on TeletextPageType::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. A page type as defined in the standard ETSI EN 300 468, Table 94
Variants (Non-exhaustive)§
This enum is marked as non-exhaustive
PageTypeAddlInfo
PageTypeHearingImpairedSubtitle
PageTypeInitial
PageTypeProgramSchedule
PageTypeSubtitle
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 TeletextPageType
impl TeletextPageType
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 TeletextPageType
impl AsRef<str> for TeletextPageType
source§impl Clone for TeletextPageType
impl Clone for TeletextPageType
source§fn clone(&self) -> TeletextPageType
fn clone(&self) -> TeletextPageType
1.0.0 · source§fn clone_from(&mut self, source: &Self)
fn clone_from(&mut self, source: &Self)
source
. Read moresource§impl Debug for TeletextPageType
impl Debug for TeletextPageType
source§impl Display for TeletextPageType
impl Display for TeletextPageType
source§impl From<&str> for TeletextPageType
impl From<&str> for TeletextPageType
source§impl FromStr for TeletextPageType
impl FromStr for TeletextPageType
source§impl Hash for TeletextPageType
impl Hash for TeletextPageType
source§impl Ord for TeletextPageType
impl Ord for TeletextPageType
source§fn cmp(&self, other: &TeletextPageType) -> Ordering
fn cmp(&self, other: &TeletextPageType) -> 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 TeletextPageType
impl PartialEq for TeletextPageType
source§fn eq(&self, other: &TeletextPageType) -> bool
fn eq(&self, other: &TeletextPageType) -> bool
self
and other
values to be equal, and is used
by ==
.source§impl PartialOrd for TeletextPageType
impl PartialOrd for TeletextPageType
source§fn partial_cmp(&self, other: &TeletextPageType) -> Option<Ordering>
fn partial_cmp(&self, other: &TeletextPageType) -> 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 TeletextPageType
impl StructuralPartialEq for TeletextPageType
Auto Trait Implementations§
impl Freeze for TeletextPageType
impl RefUnwindSafe for TeletextPageType
impl Send for TeletextPageType
impl Sync for TeletextPageType
impl Unpin for TeletextPageType
impl UnwindSafe for TeletextPageType
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