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