diff --git a/ast.ml b/ast.ml
index 16e389d..0ac79c4 100644
--- a/ast.ml
+++ b/ast.ml
@@ -14,7 +14,7 @@ type t =
   | Binop of t * operator * t
   | If of t * t * t (* cond then else *)
   | Apply of t * t list (* function application *)
-  (* these will be seperated into (toplevel) directives. *)
+  (* these will be seperated into external functions. *)
   | Set_binop_pre of operator * t
   | Get_binop_pre of operator
   | Set_binop_aso of operator * string