diff --git a/regression/common.ml b/regression/common.ml
index 924f31344..fa06cbe4e 100644
--- a/regression/common.ml
+++ b/regression/common.ml
@@ -9,7 +9,7 @@ let state ps = List.fold_right (fun (x, v) (s, p) -> Expr.update x v s, (x =:= !
 let eval  (s, p) e =
   let orig      = Expr.eval s e in
   let stmt      = List.fold_right (fun p s -> p |> s) p (Stmt.Write e) in
-  let [s_orig]  = Stmt.eval [] stmt in
+  let [s_orig]  = eval [] stmt in
   let [sm_orig] = SM.run [] (SM.compile stmt) in
   if conj (orig = s_orig) (orig = sm_orig)
   then Printf.printf "%d\n" orig
diff --git a/src/Syntax.ml b/src/Syntax.ml
index 9701f0951..dae24127b 100644
--- a/src/Syntax.ml
+++ b/src/Syntax.ml
@@ -68,3 +68,17 @@ module Stmt =
     let eval _ = failwith "Not implemented yet"
                                                          
   end
+
+(* The top-level definitions *)
+
+(* The top-level syntax category is statement *)
+type t = Stmt.t    
+
+(* Top-level evaluator
+
+     eval : int list -> t -> int list
+
+   Takes a program and its input stream, and returns the output stream
+*)
+let eval i p =
+  let _, _, o = Stmt.eval (Expr.empty, i, []) p in o