evaluator/
environment.rs

1use std::collections::HashMap;
2use std::rc::Rc;
3use std::cell::RefCell;
4use crate::object::Object;
5
6pub type Env = Rc<RefCell<Environment>>;
7
8#[derive(Debug, Default, Clone, PartialEq)]
9pub struct Environment {
10    store: HashMap<String, Rc<Object>>,
11    outer: Option<Env>
12}
13
14impl Environment {
15    
16    pub fn new_enclosed_environment(outer: &Env) -> Self {
17        let mut env: Environment = Default::default();
18        env.outer = Some(Rc::clone(outer));
19        return env;
20    }
21
22    pub fn get(&self, name: &str) -> Option<Rc<Object>> {
23        match self.store.get(name) {
24            Some(obj) => Some(Rc::clone(obj)),
25            None => {
26                if let Some(outer) = &self.outer {
27                    return outer.borrow().get(name);
28                } else {
29                    return None;
30                }
31            }
32        }
33
34    }
35
36    pub fn set(&mut self, name: String, val: Rc<Object>) {
37        self.store.insert(name, val);
38    }
39}
evaluator/environment.rs

evaluator/
environment.rs
