Struct ExprPool 

pub struct ExprPool { /* private fields */ }

Arena-like pool for Expr values backed by a hash-consing table.

ExprPool layers GC-root tracking on top of ExprHashcons. Any expression added via add_root (or subsequently marked with mark_root) is considered live.

Implementations

impl ExprPool

pub fn new() -> Self

Create a new, empty pool.

pub fn add(&mut self, expr: Expr) -> ExprId

Intern an expression without marking it as a root.

pub fn add_root(&mut self, expr: Expr) -> ExprId

Intern an expression and mark it as a GC root.

pub fn get(&self, id: ExprId) -> Option<&Expr>

Look up an expression by ID.

pub fn mark_root(&mut self, id: ExprId)

Mark an existing interned expression as a GC root.

If id is already a root it will appear twice in roots; live_count uses a deduplicated count so this is harmless.

pub fn live_count(&self) -> usize

Return the number of distinct live (root) expressions.

Duplicates in roots are ignored.

pub fn total_count(&self) -> usize

Return the total number of distinct expressions in the pool.

pub fn dedup_ratio(&self) -> f64

Compute the deduplication ratio: hits / total intern calls.

A value close to 1.0 means most add/add_root calls were satisfied from cache.

pub fn get_id(&self, expr: &Expr) -> Option<ExprId>

Look up the for a structurally equal expression, if interned.

Trait Implementations

impl Default for ExprPool

fn default() -> Self

Returns the “default value” for a type.