Struct ExprHashcons 

pub struct ExprHashcons { /* private fields */ }

Hash-consing table for Expr values.

Every unique expression (by structural equality) is assigned a stable ExprId. Subsequent intern calls for the same expression return the same ExprId and increment hit_count.

Implementations

impl ExprHashcons

pub fn new() -> Self

Create a new, empty hash-consing table.

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

Intern an expression.

Returns (id, was_new) where was_new is true if this expression had never been interned before.

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

Look up an expression by ExprId.

Returns None if the ID is out of range (should not happen for IDs produced by this table).

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

Find the ExprId for a structurally equal expression, if it exists.

Does not update hit/miss counters.

pub fn size(&self) -> usize

Return the number of distinct expressions currently interned.

pub fn hit_rate(&self) -> f64

Compute the cache hit rate as a value in [0.0, 1.0].

Returns 0.0 if no intern calls have been made.

pub fn stats(&self) -> String

Return a formatted statistics string.

Trait Implementations

impl Default for ExprHashcons

fn default() -> Self

Returns the “default value” for a type.