Struct VarSymbolMapping 

pub struct VarSymbolMapping { /* private fields */ }

Bidirectional mapping between VarId and SymbolId.

Uses SlotMap for stable VarId generation that supports deletion.

This provides:

• VarId → SymbolId: O(1) via SlotMap
• SymbolId → VarId: O(1) via SecondaryMap

Usage

let mut mapping = VarSymbolMapping::new();

// Register a variable
let var_id = mapping.register(symbol_id);

// Lookup
let sym = mapping.to_symbol(var_id);
let var = mapping.to_var(symbol_id);

// Remove (for incremental updates)
mapping.remove(var_id);

Implementations

impl VarSymbolMapping

pub fn new() -> Self

Create a new empty mapping.

pub fn with_capacity(capacity: usize) -> Self

Create with pre-allocated capacity.

pub fn register(&mut self, symbol_id: SymbolId) -> VarId

Register a named variable (with SymbolId) and return its VarId.

If the SymbolId is already registered, returns the existing VarId.

pub fn allocate(&mut self) -> VarId

Allocate a fresh VarId for a local variable without a SymbolId.

Always creates a new unique VarId. No reverse lookup is registered.

pub fn remove(&mut self, var_id: VarId) -> Option<SymbolId>

Remove a variable by VarId.

Returns the associated SymbolId if it existed.

pub fn remove_by_symbol(&mut self, symbol_id: SymbolId) -> Option<VarId>

Remove a variable by SymbolId.

Returns the VarId if it existed.

pub fn to_symbol(&self, var_id: VarId) -> Option<SymbolId>

Get the SymbolId for a VarId.

Returns None if the VarId doesn’t exist or has no associated SymbolId.

pub fn to_var(&self, symbol_id: SymbolId) -> Option<VarId>

Get the VarId for a SymbolId.

Returns None if the SymbolId is not registered.

pub fn contains_symbol(&self, symbol_id: SymbolId) -> bool

Check if a SymbolId is registered.

pub fn contains_var(&self, var_id: VarId) -> bool

Check if a VarId is valid.

pub fn len(&self) -> usize

Get the number of registered variables.

pub fn is_empty(&self) -> bool

Check if empty.

pub fn iter(&self) -> impl Iterator<Item = (VarId, Option<SymbolId>)> + '_

Iterate over all (VarId, Option<SymbolId>) pairs.

pub fn clear(&mut self)

Clear all mappings.

Trait Implementations

impl Clone for VarSymbolMapping

fn clone(&self) -> VarSymbolMapping

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for VarSymbolMapping

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

Formats the value using the given formatter.

impl Default for VarSymbolMapping

fn default() -> VarSymbolMapping

Returns the “default value” for a type.