Struct Environment 

pub struct Environment { /* private fields */ }

Scoped variable environment using a stack of hash maps.

Variables are looked up from the innermost scope outward. Assignments respect mutability — attempting to assign to an immutable binding produces a RuntimeError.

Implementations

impl Environment

pub fn new() -> Self

Creates a new environment with a single (global) scope.

pub fn push_scope(&mut self)

Pushes a new empty scope onto the stack.

pub fn pop_scope(&mut self)

Pops the innermost scope from the stack.

pub fn define(&mut self, name: String, value: Value, mutable: bool)

Defines a new variable in the current (innermost) scope.

pub fn get(&self, name: &str) -> Option<&Value>

Looks up a variable by name, searching from innermost to outermost scope.

pub fn set(&mut self, name: &str, value: Value) -> Result<(), RuntimeError>

Sets an existing variable’s value. Returns an error if the variable is not found or is immutable.

Trait Implementations

impl Clone for Environment

fn clone(&self) -> Environment

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Environment

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

Formats the value using the given formatter.

impl Default for Environment

fn default() -> Self

Returns the “default value” for a type.