Class Composition

#include <boost/mpl/inherit.hpp>
#include <boost/mpl/inherit_linearly.hpp>
#include <boost/lambda/construct.hpp>

namespace pst {
  namespace mpl = boost::mpl;
  namespace lam = boost::lambda;
  using mpl::_1; using mpl::_2;

  template <typename Sequence>
  struct factory
    : mpl::inherit_linearly< Sequence, mpl::inherit< _1, lam::new_ptr<_2> > >::type { };
} // pst

#include <string>
#include <list>
#include <boost/mpl/vector.hpp>

int main() {
  using namespace std;
  namespace mpl = boost::mpl;
  namespace lam = boost::lambda;

  typedef mpl::vector<string,list<int>,char> t_types;
  pst::factory<t_types> a_factory;

  string* ps = static_cast< lam::new_ptr<string> >(a_factory)();
  list<int>* pl = static_cast< lam::new_ptr< list<int > > >(a_factory)();
  char* pc = static_cast< lam::new_ptr<char> >(a_factory)();
  return 0;
}

letsboost::mpl
C++ Template Metaprogramming Section 9.5