Re: [Boost-users] [fusion] How to create an object of my fusion generated type?

From: Christian Henning (chhenning_at_[hidden])
Date: 2007-03-19 15:38:44

My fault. I was using forward class declarations instead of class
definitions. This works now:

#include <vector>

#include <boost/mpl/assert.hpp>
#include <boost/mpl/equal.hpp>
#include <boost/mpl/list.hpp>
#include <boost/mpl/transform.hpp>

#include <boost/fusion/algorithm/transformation/transform.hpp>
#include <boost/fusion/algorithm/iteration/for_each.hpp>
#include <boost/fusion/sequence/adapted/mpl.hpp>
#include <boost/fusion/sequence/container.hpp>
#include <boost/fusion/sequence/conversion/as_list.hpp>

using namespace std;
using namespace boost;

template <typename T>
struct add_vector
{
   typedef std::vector<T> type;
};

struct A { void print() { cout << "A" << endl; }};
struct B { void print() { cout << "B" << endl; }};
struct C { void print() { cout << "C" << endl; }};

struct create_empty_vec
{
   template< class T >
   std::vector<T> operator()( T& t ) const
   {
      return std::vector<T>();
   }
};

struct add_one
{
   template< class T >
   void operator()( T& vec ) const
   {
      vec.push_back( T::value_type() );
   }
};

struct print
{
   template< class T >
   void operator()( T& vec ) const
   {
      vec[0].print();
   }
};

int main()
{
   typedef mpl::list< A, B, C > _types_;
   typedef mpl::transform1< _types_, add_vector<mpl::_1> >::type
_mpl_list_of_vectors_;

   typedef fusion::result_of::as_list<_mpl_list_of_vectors_>::type
_fusion_list_of_vectors_;

   _fusion_list_of_vectors_ vectors;
   fusion::for_each( vectors, create_empty_vec() );

   fusion::for_each( vectors, add_one() );

   fusion::for_each( vectors, print() );

   return 0;
}

Sorry for the noise,
Christian