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.

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.