object/
environment.rs

1use crate::Object;
2use std::cell::RefCell;
3use std::collections::HashMap;
4use std::rc::Rc;
5
6pub type Env = Rc<RefCell<Environment>>;
7
8#[derive(Debug, Default, Eq, Clone, PartialEq)]
9pub struct Environment {
10    store: HashMap<String, Rc<Object>>,
11    outer: Option<Env>,
12}
13
14impl Environment {
15    pub fn new_enclosed_environment(outer: &Env) -> Self {
16        let mut env: Environment = Default::default();
17        env.outer = Some(Rc::clone(outer));
18        return env;
19    }
20
21    pub fn get(&self, name: &str) -> Option<Rc<Object>> {
22        match self.store.get(name) {
23            Some(obj) => Some(Rc::clone(obj)),
24            None => {
25                if let Some(outer) = &self.outer {
26                    return outer.borrow().get(name);
27                } else {
28                    return None;
29                }
30            }
31        }
32    }
33
34    pub fn set(&mut self, name: String, val: Rc<Object>) {
35        self.store.insert(name, val);
36    }
37
38    pub fn visible_names(&self) -> Vec<String> {
39        let mut names = self
40            .outer
41            .as_ref()
42            .map(|outer| outer.borrow().visible_names())
43            .unwrap_or_default();
44        names.extend(self.store.keys().cloned());
45        names
46    }
47}
object/environment.rs

object/
environment.rs
