snd (List.assoc name env)
with Not_found -> raise (Value_not_found name)
-let remove env name = List.remove_assoc name env
+let remove_name env name = List.remove_assoc name env
+
+let remove_names env names =
+ List.filter (fun name, _ -> not (List.mem name names)) env
let lookup_term env name =
match lookup env name with