feat: SCC analysis (WIP)

src/engine/mod.rs

@@ -27,7 +27,7 @@ pub struct Engine {
 pub fn eval(downgraded: Downgraded) -> Result<Value> {
     let mut engine = Engine::new(downgraded.thunks, downgraded.func_offset);
     engine
-        .eval(downgraded.top_level, &mut VmEnv::new())
+        .eval()
         .map(|mut val| {
             Ok(val
                 .force(&mut engine)?
@@ -38,15 +38,15 @@ pub fn eval(downgraded: Downgraded) -> Result<Value> {
 impl Engine {
     pub fn new(thunks: Box<[Ir]>, func_offset: usize) -> Self {
         Self {
-            lru: LruCache::new(thunks.len().clamp(1, usize::MAX).try_into().unwrap()),
+            lru: LruCache::new(thunks.len().try_into().unwrap()),
             thunks,
             func_offset,
             tasks: PriorityQueue::new(),
         }
     }
 
-    pub fn eval(&mut self, expr: Ir, env: &mut VmEnv) -> Result<i::Value> {
-        expr.eval(self, env)
+    pub fn eval(&mut self) -> Result<i::Value> {
+        self.thunks.last().unwrap().clone().eval(self, &mut VmEnv::new())
     }
 
     pub fn eval_thunk(&mut self, idx: usize, env: &mut VmEnv) -> Result<i::Value> {