monkey-object 1.1.0

a object system for monkey lang
Documentation 
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use crate::Object;
use std::cell::RefCell;
use std::collections::HashMap;
use std::rc::Rc;

pub type Env = Rc<RefCell<Environment>>;

#[derive(Debug, Default, Eq, Clone, PartialEq)]
pub struct Environment {
    store: HashMap<String, Rc<Object>>,
    outer: Option<Env>,
}

impl Environment {
    pub fn new_enclosed_environment(outer: &Env) -> Self {
        return Environment {
            outer: Some(Rc::clone(outer)),
            ..Default::default()
        };
    }

    pub fn get(&self, name: &str) -> Option<Rc<Object>> {
        match self.store.get(name) {
            Some(obj) => Some(Rc::clone(obj)),
            None => {
                if let Some(outer) = &self.outer {
                    return outer.borrow().get(name);
                } else {
                    return None;
                }
            }
        }
    }

    pub fn set(&mut self, name: String, val: Rc<Object>) {
        self.store.insert(name, val);
    }

    pub fn visible_names(&self) -> Vec<String> {
        let mut names = self
            .outer
            .as_ref()
            .map(|outer| outer.borrow().visible_names())
            .unwrap_or_default();
        names.extend(self.store.keys().cloned());
        names
    }
}