I wanted to add the final touch, from :
template <typename Seq> struct overload : detail::compose_overload_base<Seq>::type { typedef typename tuples::element<0, Seq>::type Sig0; typedef typename tuples::element<1, Seq>::type Sig1; typedef typename tuples::element<2, Seq>::type Sig2; typedef typename tuples::element<3, Seq>::type Sig3;
typedef tuple< boost::function<Sig0> , boost::function<Sig1> , boost::function<Sig2> , boost::function<Sig3> > functions_type;
to namespace detail { struct get_function { template <typename T> struct apply { typedef boost::function<T> type; }; }; } template <typename Seq> struct overload : detail::compose_overload_base<Seq>::type { typedef typename boost::mpl:: transform<Seq, detail::get_function>::type functions_type; But i have a strange compile error. [snip] overload.cpp:45: instantiated from here boost_dir/boost/mpl/clear.hpp:31: error: invalid use of incomplete type 'struct boost::mpl::clear_impl<boost::mpl::non_sequence_tag>::apply<boost::tuples::tuple<int ()(char), double ()(int, char), char ()(std::string), v [snip] I have included #include <boost/mpl/transform.hpp> but proabbly I'm missing something... Could someone help me? I'm new to boost. Thanks Marco