Struct ColumnarStore 

pub struct ColumnarStore { /* private fields */ }

Column-oriented storage for entity tags, indexed by entity ID.

Each “column” is a Vec<Option<Kind>> where index i corresponds to entity ID i. Missing entities or missing tags for that entity are None.

Benefits:

• Sequential memory access when scanning a single tag across all entities
• Cache-line prefetching works optimally (no pointer chasing through HDict)
• Natural alignment with bitmap indexes (same entity ID space)

Implementations

impl ColumnarStore

pub fn new() -> Self

pub fn track_tag(&mut self, tag: &str)

Register a tag to be tracked as a column. Must call rebuild() after registering new tags to populate from existing entities.

pub fn is_tracked(&self, tag: &str) -> bool

Returns true if the given tag is tracked as a column.

pub fn set(&mut self, eid: usize, tag: &str, value: &Kind)

Set the value for entity eid at the given tag column.

pub fn clear_entity(&mut self, eid: usize)

Clear the value for entity eid at the given tag column.

pub fn ensure_capacity(&mut self, new_capacity: usize)

Ensure all columns can hold at least new_capacity entries.

pub fn column(&self, tag: &str) -> Option<&[Option<Kind>]>

Get a column slice for a tracked tag. Returns None if the tag is not tracked.

pub fn get(&self, eid: usize, tag: &str) -> Option<&Kind>

Get the value for a specific entity and tag.

pub fn scan_column<F>(&self, tag: &str, predicate: F) -> Vec<usize>

where F: Fn(&Kind) -> bool,

Scan a column and return entity IDs where the predicate matches. This is the primary performance advantage: sequential memory access.

pub fn column_count(&self) -> usize

Number of tracked columns.

pub fn capacity(&self) -> usize

Current capacity (max entity IDs).

pub fn clear(&mut self)

Clear all column data (keeps tracked tags registered).

pub fn tracked_tags(&self) -> &[String]

Tracked tag names.

Trait Implementations

impl Default for ColumnarStore

fn default() -> Self

Returns the “default value” for a type.