Struct PreparedQuery 

pub struct PreparedQuery<Q: Query> { /* private fields */ }

A prepared query can be stored independently of the Substrate to fractionally reduce query set-up costs.

Prepared queries are less convenient and usually do not measurably impact performance. Regular queries should be preferred unless end-to-end performance measurements clearly indicate otherwise.

Implementations

impl<Q: Query> PreparedQuery<Q>

pub fn new() -> Self

Create a prepared query which is not yet attached to any world

pub fn query<'q>( &'q mut self, world: &'q Substrate, ) -> PreparedQueryBorrow<'q, Q>

Query world, using dynamic borrow checking

This will panic if it would violate an existing unique reference or construct an invalid unique reference.

pub fn query_mut<'q>( &'q mut self, world: &'q mut Substrate, ) -> PreparedQueryIter<'q, Q>

Query a uniquely borrowed world

Avoids the cost of the dynamic borrow checking performed by query.

pub fn view_mut<'q>( &'q mut self, world: &'q mut Substrate, ) -> PreparedView<'q, Q>

Provide random access to query results for a uniquely borrow world

Trait Implementations

impl<Q: Query> Default for PreparedQuery<Q>

fn default() -> Self

Returns the “default value” for a type.