diff --git a/lex.ml b/lex.ml
index 93afc86..6827430 100644
--- a/lex.ml
+++ b/lex.ml
@@ -57,13 +57,13 @@ let rec partition_while f seq : 'a Seq.t * 'a Seq.t =
 
 let tokenize (str : string) : tokens =
   let seq = String.to_seq str in
-  let rec aux seq () =
+  let rec aux seq =
     let open Token in
     match seq () with
-    | Seq.Nil -> Seq.Nil
+    | Seq.Nil -> Seq.empty
     | Seq.Cons (x, seq) ->
       if is_whitespace x then
-        aux seq () (* skip whitespace *)
+        aux seq (* skip whitespace *)
 
       else if x = '"' then
         let str, seq = partition_while ((<>) '"') seq in
@@ -71,7 +71,7 @@ let tokenize (str : string) : tokens =
         begin match seq () with
           | Seq.Nil -> raise Unclosed_quote
           | Seq.Cons (x, seq) ->
-            if x = '"' then Seq.Cons (Value str, aux seq)
+            if x = '"' then Seq.cons (Value str) (aux seq)
             else raise Unclosed_quote
         end
 
@@ -83,16 +83,16 @@ let tokenize (str : string) : tokens =
           then Float (float_of_string n)
           else Int (int_of_string n)
         in
-        Seq.Cons (Value n, aux seq)
+        Seq.cons (Value n) (aux seq)
 
       else if is_ident_start x then
         let id, seq = partition_while is_ident seq in
         let id = String.of_seq @@ Seq.cons x id in
-        Seq.Cons (Ident id, aux seq)
+        Seq.cons (Ident id) (aux seq)
 
       else
         match find_token @@ Seq.cons x seq with
         | None -> raise Token_not_found
-        | Some (t, s) -> Seq.Cons (t, aux s)
+        | Some (t, seq) -> Seq.cons t (aux seq)
   in
   aux seq