Struct VarMap 

pub struct VarMap(/* private fields */);

Maps VarIds to DataFusion column name strings.

The binder allocates one VarId per distinct bound variable in a query (e.g. a, b, r). VarMap records the DataFusion column name each variable resolves to at execution time — typically "<alias>.node_id" for node variables and "<alias>.edge_id" for edge variables.

Implementations

impl VarMap

pub fn new() -> Self

Creates an empty map.

pub fn insert(&mut self, var: VarId, col_name: impl Into<String>)

Records that variable var maps to DataFusion column col_name.

pub fn clear(&mut self)

Drops every registered variable. Used to install a fresh WITH scope so pre-WITH variables stop resolving (mirrors the binder’s scope reset).

pub fn get(&self, var: VarId) -> Option<&str>

Returns the column name for var, or None if it has not been registered.

pub fn var_ids(&self) -> impl Iterator<Item = VarId> + '_

Iterates the VarIds currently registered, in arbitrary order.

Used to compute the variables shared between two scopes (e.g. the outer and optional sides of an OPTIONAL MATCH, which become its join keys).

Trait Implementations

impl Clone for VarMap

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VarMap

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

Formats the value using the given formatter.

impl Default for VarMap

fn default() -> Self

Returns the “default value” for a type.