#include <string>

#include <boost/bind/arg.hpp>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/sequenced_index.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/mem_fun.hpp>

using namespace boost;
using namespace boost::multi_index;

class Variable_declaration {
public:
    const std::string& name() const;
};        

struct Variables
{
    typedef multi_index_container<
        Variable_declaration,
        indexed_by<
        sequenced<>,
        ordered_non_unique<const_mem_fun<Variable_declaration,
                                         const std::string&,
                                         &Variable_declaration::name> >
    > > variables_t;
    
    variables_t variable_declarations;
};