#include <boost/preprocessor/list/to_array.hpp>
#define LIST (a, (b, (c, BOOST_PP_NIL)))
BOOST_PP_LIST_TO_ARRAY(LIST) // expands to (3, (a, b, c))
Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at www.boost.org/LICENSE_1_0.txt)