Struct Env

pub struct Env { /* private fields */ }

An environment of symbol bindings. Used for the base environment, for closures, for let statements, for function arguments, etc.

Implementations

impl Env

pub fn new() -> Self

Create a new, empty environment

pub fn extend(parent: Rc<RefCell<Env>>) -> Self

Create a new environment extending the given environment

pub fn get(&self, key: &Symbol) -> Option<Value>

Walks up the environment hierarchy until it finds the symbol’s value or runs out of environments.

pub fn define(&mut self, key: Symbol, value: Value)

Define a new key in the current environment

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

Find the environment where this key is defined, and update its value. Returns an Err if the symbol has not been defined anywhere in the hierarchy.

pub fn undefine(&mut self, key: &Symbol)

Delete the nearest (going upwards) definition of this key

Trait Implementations

impl Debug for Env

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

Formats the value using the given formatter.

impl Display for Env

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

Formats the value using the given formatter.