Struct LexicalEnv 

pub struct LexicalEnv { /* private fields */ }

A lexical scope: a frame of name-to-value slots chained to its parent.

Cloning shares the same frame; child opens a nested scope. Slots support deferred initialization so letrec can predefine names before computing their values.

Implementations

impl LexicalEnv

pub fn new() -> Self

Creates a fresh root scope with no parent and no bindings.

pub fn child(&self) -> Self

Opens a nested scope whose lookups fall through to this one.

pub fn define(&self, name: Symbol, value: Value) -> Result<()>

Binds name to value in this frame.

Errors if name is already bound in the same frame (shadowing requires a child scope).

pub fn lookup(&self, name: &Symbol) -> Result<Value>

Resolves name through this frame and its parents.

Errors if the name is undefined or was predefined but never initialized.

pub fn capture_cell(&self, name: &Symbol) -> Result<BindingCell>

Captures name as a shared cell for closure formation.

Mutating the returned cell updates the lexical slot itself, so every closure that captures the same binding observes the same value.

Trait Implementations

impl Clone for LexicalEnv

fn clone(&self) -> LexicalEnv

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for LexicalEnv

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

Formats the value using the given formatter.

impl Default for LexicalEnv

fn default() -> Self

Returns the “default value” for a type.