not-python-old.2020-08-27/src/vm/frame.rs

use crate::{
    obj::prelude::*,
    vm::op::Op,
};
use std::rc::Rc;

pub struct Frame {
    stack: Vec<DynRef>,
    ip: usize,
    return_value: Option<DynRef>,
    locals: Ns,
    ops: Rc<Vec<Op>>,
}

impl Frame {
    pub fn new(ops: Rc<Vec<Op>>) -> Self {
        Frame {
            stack: Default::default(),
            ip: 0,
            return_value: None,
            locals: Default::default(),
            ops,
        }
    }

    pub fn push(&mut self, obj_ref: DynRef) {
        self.stack.push(obj_ref)
    }
    
    pub fn pop(&mut self) -> Option<DynRef> {
        self.stack.pop()
    }

    pub fn ip(&self) -> usize {
        self.ip
    }

    pub fn set_ip(&mut self, ip: usize) {
        self.ip = ip;
    }

    pub fn return_value(&self) -> Option<DynRef> {
        self.return_value
    }

    pub fn set_return_value(&mut self, obj_ref: DynRef) {
        self.return_value = Some(obj_ref);
    }

    pub fn get_local(&self, sym: Sym) -> Option<DynRef> {
        self.locals.get(&sym).copied()
    }

    pub fn set_local(&mut self, sym: Sym, obj_ref: DynRef) -> Option<DynRef> {
        self.locals.insert(sym, obj_ref)
    }

    pub fn ops(&self) -> &Rc<Vec<Op>> {
        &self.ops
    }
}