+/* Returns true if ACTUAL_TYPE is a kind of REQUIRED_TYPE, false
+ otherwise. */
+static bool
+is_compatible (atom_type required_type, atom_type actual_type)
+{
+ return (required_type == actual_type
+ || (required_type == OP_var
+ && (actual_type == OP_num_var || actual_type == OP_str_var)));
+}
+