[fine] WIP: Classes

fine/tests/expression/lists.fine

@@ -1,10 +1,14 @@
 fun sum(x: list<f64>) -> f64 {
-  75 // lol
+  let result = 0;
+  for v in x {
+    result = result + v;
+  }
+  result
 }
 
-fun test() {
+fun test() -> f64 {
   let val = [1, 2, 3];
-  sum(val);
+  sum(val)
 }
 
 // @no-errors