Struct OptionQuery

pub struct OptionQuery<V, F>
where
    F: Convert<V>,
{ /* private fields */ }

This is a query that expects an optional single item.

Construct this using [‘Queries::option’].

If the sequence is empty, None is returned. If it contains more than one item, an error is returned.

The result is converted into a Rust value using the convert function when constructing this query.

This is useful if you expect an optional single item to be returned from an XPath query.

Implementations

impl<V, F> OptionQuery<V, F>

where F: Convert<V>,

pub fn execute_with_context( &self, document: &mut Documents, context: &DynamicContext<'_>, ) -> Result<Option<V>>

Execute the query against an itemable, with explicit dynamic context.

Trait Implementations

impl<V: Clone, F> Clone for OptionQuery<V, F>

where F: Convert<V> + Clone,

fn clone(&self) -> OptionQuery<V, F>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<V: Debug, F> Debug for OptionQuery<V, F>

where F: Convert<V> + Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<V, F> Query<Option<V>> for OptionQuery<V, F>

where F: Convert<V>,

fn program(&self) -> &Program

Get the program for the query

fn execute_with_context( &self, document: &mut Documents, context: &DynamicContext<'_>, ) -> Result<Option<V>>

Execute the query against a dynamic context

fn static_context(&self) -> &StaticContext

Get the static context for the query.

fn dynamic_context_builder( &self, documents: &Documents, ) -> DynamicContextBuilder<'_>

Get a dynamic context builder for the query, configured with the query’s static context and the document’s documents.

fn map<T, F>(self, f: F) -> MapQuery<V, T, Self, F>

where Self: Sized, F: Fn(V, &mut Documents, &DynamicContext<'_>) -> Result<T> + Clone,

Map the the result of the query to a different type.

fn execute(&self, documents: &mut Documents, item: impl Itemable) -> Result<V>

Excute the query against an itemable

fn execute_build_context( &self, documents: &mut Documents, build: impl FnOnce(&mut DynamicContextBuilder<'_>), ) -> Result<V>

Execute a query with a specific dynamic context.