Struct ViewBorrow

pub struct ViewBorrow<'w, Q>
where
    Q: Query,
{ /* private fields */ }

A borrow of a World sufficient to random-access the results of the query Q.

Note that borrows are not released until this object is dropped.

This struct is a thin wrapper around View. See it for more documentation.

Implementations

impl<'w, Q> ViewBorrow<'w, Q>

where Q: Query,

pub fn get(&self, entity: Entity) -> Option<<Q as Query>::Item<'_>>

where Q: QueryShared,

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

Does not require exclusive access to the map, but is defined only for queries yielding only shared references.

See `View::get``.

pub fn get_mut(&mut self, entity: Entity) -> Option<<Q as Query>::Item<'_>>

Retrieve the query results corresponding to entity

Will yield None if the entity does not exist or does not match the query.

See `View::get_mut``.

pub fn contains(&self, entity: Entity) -> bool

Equivalent to get(entity).is_some(), but does not require Q: QueryShared

See `View::contains``.

pub unsafe fn get_unchecked( &self, entity: Entity, ) -> Option<<Q as Query>::Item<'_>>

Like get_mut, but allows simultaneous access to multiple entities

See `View::get_unchecked``.

Safety

Must not be invoked while any unique borrow of the fetched components of entity is live.

pub fn get_many_mut<const N: usize>( &mut self, entities: [Entity; N], ) -> [Option<<Q as Query>::Item<'_>>; N]

Like get_mut, but allows checked simultaneous access to multiple entities

For N > 3, the check for distinct entities will clone the array and take O(N log N) time.

See `View::get_many_mut``.

Examples

let mut world = World::new();

let a = world.spawn((1, 1.0));
let b = world.spawn((2, 4.0));
let c = world.spawn((3, 9.0));

let mut view = world.view_mut::<&mut i32>();
let [a, b, c] = view.get_mut_n([a, b, c]);

assert_eq!(*a.unwrap(), 1);
assert_eq!(*b.unwrap(), 2);
assert_eq!(*c.unwrap(), 3);

pub fn iter_mut(&mut self) -> ViewIter<'_, Q>

Iterate over all entities satisfying Q

See `View::iter_mut``

Trait Implementations

impl<'w, Q> Drop for ViewBorrow<'w, Q>

where Q: Query,

fn drop(&mut self)

Executes the destructor for this type.

impl<'a, 'q, Q> IntoIterator for &'a mut ViewBorrow<'q, Q>

where Q: Query,

type IntoIter = ViewIter<'a, Q>

Which kind of iterator are we turning this into?

type Item = (Entity, <Q as Query>::Item<'a>)

The type of the elements being iterated over.

fn into_iter(self) -> <&'a mut ViewBorrow<'q, Q> as IntoIterator>::IntoIter

Creates an iterator from a value.