Enum Alt

pub enum Alt<T: ?Sized> {
    Alt,
    // some variants omitted
}

Query that yields wrapped mutable reference to specified component for each entity that has that component.

Skips entities that don’t have the component.

Works almost as &mut T does. However, it does not updates entity epoch unless returned reference wrapper is dereferenced.

Variants

Alt

Instance of this type.

Implementations

impl<T: ?Sized> Alt<T>

pub const fn new() -> Self

Constructs new marker instance. This function is noop as it returns ZST and have no side-effects.

Trait Implementations

impl<T> AsQuery for Alt<T>

where T: 'static,

type Query = Alt<T>

Associated query type.

impl<T: ?Sized> Clone for Alt<T>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<T> Debug for Alt<T>

where T: 'static + ?Sized,

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

Formats the value using the given formatter.

impl<T: ?Sized> Default for Alt<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T> DefaultQuery for Alt<T>

where T: 'static,

fn default_query() -> Self

Returns default query instance.

impl<T> IntoQuery for Alt<T>

where T: 'static,

fn into_query(self) -> Self

Converts into query.

impl<T> Query for Alt<T>

where T: 'static,

const MUTABLE: bool = true

Set to true if query fetches at least one mutable component.

type Item<'a> = RefMut<'a, T>

Item type this query type yields.

type Fetch<'a> = FetchAlt<'a, T>

Fetch value type for this query type. Contains data from one archetype.

fn component_access( &self, comp: &ComponentInfo, ) -> Result<Option<Access>, WriteAlias>

Returns what kind of access the query performs on the component type. This method may return stronger access type if it is impossible to know exact access with only type-id.

fn visit_archetype(&self, archetype: &Archetype) -> bool

Checks if archetype must be visited or skipped. If returns false, access_archetype and fetch must not be called, meaning that complex query should either skip archetype entirely or for this query specifically.

unsafe fn access_archetype( &self, _archetype: &Archetype, f: impl FnMut(TypeId, Access), )

Asks query to provide types and access for the specific archetype. Must call provided closure with type id and access pairs. Only types from archetype must be used to call closure.

unsafe fn fetch<'a>( &self, _arch_idx: u32, archetype: &'a Archetype, epoch: EpochId, ) -> FetchAlt<'a, T>

Fetches data from one archetype.

const FILTERS_ENTITIES: bool = false

Set to true if query filters individual entities.

fn visit_archetype_late(&self, archetype: &Archetype) -> bool

Checks if archetype must be visited or skipped a second time after required access was granted.

fn reserved_entity_item<'a>( &self, id: EntityId, idx: u32, ) -> Option<Self::Item<'a>>

Returns item for reserved entity if reserved entity (no components) satisfies the query. Otherwise returns None.

impl<T> QueryArg for Alt<T>

where T: Send + 'static,

fn new() -> Self

Creates new query state.

fn before(&mut self, world: &World)

Hook called before function-system runs to update the state.

fn after(&mut self, world: &World)

Hook called after function-system runs to update the state.

impl<T: ?Sized> Copy for Alt<T>

impl<T> SendQuery for Alt<T>

where T: Send + 'static,