Struct MemStore 

pub struct MemStore { /* private fields */ }

A simple in-memory implementation of Store. Supports semi-naive evaluation by tracking “stable” and “delta” facts.

Implementations

impl MemStore

pub fn new() -> Self

pub fn create_relation(&mut self, relation: &str)

Registers a relation (creating it if absent) to allow scanning it.

pub fn add_fact(&mut self, relation: &str, args: Vec<Value>)

Add a fact manually (for testing/setup). Auto-creates relation in stable.

pub fn get_facts(&self, relation: &str) -> Vec<Vec<Value>>

Trait Implementations

impl Default for MemStore

fn default() -> MemStore

Returns the “default value” for a type.

impl Store for MemStore

fn scan( &self, relation: &str, ) -> Result<Box<dyn Iterator<Item = Vec<Value>> + '_>>

Returns an iterator over all tuples in the relation. Returns an error if the relation does not exist.

fn scan_delta( &self, relation: &str, ) -> Result<Box<dyn Iterator<Item = Vec<Value>> + '_>>

Returns an iterator over only the new tuples added in the last iteration.

fn scan_next_delta( &self, relation: &str, ) -> Result<Box<dyn Iterator<Item = Vec<Value>> + '_>>

Returns an iterator over tuples being collected for the next iteration.

fn scan_index( &self, relation: &str, col_idx: usize, key: &Value, ) -> Result<Box<dyn Iterator<Item = Vec<Value>> + '_>>

Returns an iterator over tuples in the relation matching a key in a column.

fn scan_delta_index( &self, relation: &str, col_idx: usize, key: &Value, ) -> Result<Box<dyn Iterator<Item = Vec<Value>> + '_>>

Returns an iterator over delta tuples matching a key in a column.

fn insert(&mut self, relation: &str, tuple: Vec<Value>) -> Result<bool>

Inserts a tuple into the relation (specifically into the delta/new set). Returns true if it was new.

fn merge_deltas(&mut self)

Merges current deltas into the stable set of facts.

fn create_relation(&mut self, relation: &str)

Ensures a relation exists in the store.

fn retract(&mut self, relation: &str, tuple: &[Value]) -> Result<bool>

Removes a specific tuple from the relation’s stable set. Returns true if the tuple was found and removed.

fn clear(&mut self, relation: &str)

Removes all tuples from a relation (stable, delta, and next_delta).

fn relation_names(&self) -> Vec<String>

Returns the names of all relations in the store.