Add vm and compile modules

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/vm/frame.rs

@@ -0,0 +1,49 @@
+use crate::obj::prelude::*;
+use std::collections::BTreeMap;
+
+#[derive(Default)]
+pub struct Frame {
+    stack: Vec<DynRef>,
+    ip: usize,
+    return_value: Option<DynRef>,
+    locals: BTreeMap<Sym, DynRef>,
+}
+
+impl Frame {
+    pub fn new() -> Self {
+        Default::default()
+    }
+
+    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)
+    }
+}
+