#include <boost/tuple/tuple.hpp>
#include <boost/mpl/vector_c.hpp>
#include <boost/mpl/transform.hpp>
#include <boost/fusion/adapted/struct/adapt_struct.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/mpl.hpp>                  // makes params a MPL sequence
#include <boost/fusion/support/is_sequence.hpp>
#include <boost/fusion/include/is_sequence.hpp>

struct params {
  double       d1;
  double       d2;                  
  double       d3;                  
  unsigned int i4;
  unsigned int i5;
  unsigned int i6;
  unsigned int i7;
};

BOOST_FUSION_ADAPT_STRUCT(
  params,
  (double, d1)
  (double, d2)
  (double, d3)
  (unsigned int, i4)
  (unsigned int, i5)
  (unsigned int, i6)
  (unsigned int, i7)
)

BOOST_MPL_ASSERT(( boost::fusion::traits::is_sequence<params> ));  // passes

template <typename T1>
struct rangify {
  typedef boost::tuple<T1, T1, T1> type;   /// min max incr
};

template <typename T>
struct fixed_or_range {
  typedef struct {
    union {
     T                         fixed;
     typename rangify<T>::type range;
    };
    bool is_fixed;
  }
  type;
};


typedef boost::mpl::transform< params, fixed_or_range<boost::mpl::_> >::type params_fixed_or_range;