mpl/example/inherit_multiply.cpp

//-----------------------------------------------------------------------------
// boost mpl/example/inherit_multiply.cpp source file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2002
// Aleksey Gurtovoy
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee, 
// provided that the above copyright notice appears in all copies and 
// that both the copyright notice and this permission notice appear in 
// supporting documentation. No representations are made about the 
// suitability of this software for any purpose. It is provided "as is" 
// without express or implied warranty.

#include "boost/mpl/inherit.hpp"
#include "boost/mpl/inherit_linearly.hpp"
#include "boost/mpl/list.hpp"

#include <iostream>

namespace mpl = boost::mpl;
using namespace mpl::placeholder;

template< typename T >
struct tuple_field
{
    typedef tuple_field type; // note the typedef
    T field_;
};

template< typename T >
inline
T& field(tuple_field<T>& t)
{
    return t.field_;
}

typedef mpl::inherit_linearly<
      mpl::list<int,char const*,bool>
    , mpl::inherit< _1, tuple_field<_2> >
    >::type my_tuple;
    

int main()
{
    my_tuple t;
    
    field<int>(t) = -1;
    field<char const*>(t) = "text";
    field<bool>(t) = false;

    std::cout
        << field<int>(t) << '\n'
        << field<char const*>(t) << '\n'
        << field<bool>(t) << '\n'
        ;

    return 0;
}