Struct EntitySet 

pub struct EntitySet<'a, E: Entity>(/* private fields */);

Opaque public wrapper around the internal set-expression tree.

Implementations

impl<'a, E: Entity> EntitySet<'a, E>

pub fn empty() -> Self

Create an empty entity set.

pub fn union(self, other: Self) -> Self

pub fn intersection(self, other: Self) -> Self

pub fn difference(self, other: Self) -> Self

pub fn contains(&self, entity_id: EntityId<E>) -> bool

Test whether entity_id is a member of this set.

pub fn to_owned_vec(self) -> Vec<EntityId<E>>

Collect this set’s contents into an owned vector of EntityId<E>.

pub fn sample_entity_excluding<R, X>( &self, rng: &mut R, excluded: X, ) -> Option<EntityId<E>>

where R: Rng, X: Borrow<EntityId<E>>,

Sample a single entity uniformly from this set, excluding any entity equal to excluded. Returns None if the set is empty or contains only the excluded entity.

For source-leaf sets with random-access backing (PopulationRange, IndexSet), runs in O(1) with at most two index lookups and no iterator construction. Falls back to O(n) reservoir sampling for composite sets and PropertySet sources.

pub fn sample_entity<R>(&self, rng: &mut R) -> Option<EntityId<E>>

where R: Rng,

Sample a single entity uniformly from this set. Returns None if the set is empty.

pub fn count_and_sample_entity<R>( &self, rng: &mut R, ) -> (usize, Option<EntityId<E>>)

where R: Rng,

Count the entities in this set and sample one uniformly from them.

Returns (count, sample) where sample is None iff count == 0.

pub fn sample_entities<R>( &self, rng: &mut R, requested: usize, ) -> Vec<EntityId<E>>

where R: Rng,

Sample up to requested entities uniformly from this set. If the set has fewer than requested entities, the entire set is returned.

pub fn try_len(&self) -> Option<usize>

Returns Some(length) only when the set length is trivially known.

This is true only for direct SourceSet leaves except PropertySet. Composite expressions return None.

Trait Implementations

impl<'a, E: Entity> Clone for EntitySet<'a, E>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<'a, E: Entity> Default for EntitySet<'a, E>

fn default() -> Self

Returns the “default value” for a type.

impl<'a, E: Entity> IntoIterator for EntitySet<'a, E>

type Item = EntityId<E>

The type of the elements being iterated over.

type IntoIter = EntitySetIterator<'a, E>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.