Диапазоны значений перечислителей

#include <iostream>
#include <boost/bimap.hpp>
 
template<typename E>
class enums_helper
{
   typedef boost::bimaps::bimap<std::string, boost::bimaps::set_of<E>> map_t;
   typedef typename map_t::value_type value_type;
public:
   enums_helper& operator () (const E& e, const std::string& name)
   {
      if (!members.insert(value_type(name, e)).second)
      {
         throw std::logic_error("Not unique");
      }
      return *this;
   }
   const E& operator [](const std::string& name) const
   {
      return get(name);
   }
   const std::string& operator [](const E& e) const
   {
      return get(e);
   }
private:
   const E& get (const std::string& name) const
   {
      auto pos = members.left.find(name);
      if (pos == members.left.end())
      {
         throw std::logic_error("Not found by name");
      }
      return pos->second;
   }
   const std::string& get(const E& e) const
   {
      auto pos = members.right.find(e);
      if (pos == members.right.end())
      {
         throw std::logic_error("Not found by value");
      }
      return pos->second;
   }
   map_t members;
};
 
#define MakeName2(x, y) x ## y
 
#define ENUM_NAMES_DECL(Enum) \
const Enum& get_by_name(const std::string&); \
const std::string& get_by_value(const Enum&);
 
#define ENUM_NAMES_BEGIN(Enum) \
static const enums_helper<Enum> MakeName2(names, Enum) = enums_helper<Enum>()
 
#define ENUM_NAMES_END(Enum) ; \
const Enum& get_by_name(const std::string& name) { return MakeName2(names, Enum)[name]; } \
const std::string& get_by_value(const Enum& e) { return MakeName2(names, Enum)[e]; }
 
enum E
{
   first,
   second
};
 
ENUM_NAMES_DECL(E)
ENUM_NAMES_BEGIN(E)
(first, "first")
(second, "second")
ENUM_NAMES_END(E)
 
int main()
{
   std::cout << get_by_name("first") << std::endl;
   std::cout << get_by_value(second) << std::endl;
}