ceph/src/boost/libs/mpl/example/inherit_multiply.cpp

   1
   2 // Copyright Aleksey Gurtovoy 2002-2004
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // (See accompanying file LICENSE_1_0.txt or copy at
   6 // http://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // See http://www.boost.org/libs/mpl for documentation.
   9
  10 // $Id$
  11 // $Date$
  12 // $Revision$
  13
  14 #include <boost/mpl/inherit.hpp>
  15 #include <boost/mpl/inherit_linearly.hpp>
  16 #include <boost/mpl/list.hpp>
  17
  18 #include <iostream>
  19
  20 namespace mpl = boost::mpl;
  21 using namespace mpl::placeholders;
  22
  23 template< typename T >
  24 struct tuple_field
  25 {
  26     typedef tuple_field type; // note the typedef
  27     T field_;
  28 };
  29
  30 template< typename T >
  31 inline
  32 T& field(tuple_field<T>& t)
  33 {
  34     return t.field_;
  35 }
  36
  37 typedef mpl::inherit_linearly<
  38       mpl::list<int,char const*,bool>
  39     , mpl::inherit< _1, tuple_field<_2> >
  40     >::type my_tuple;
  41
  42
  43 int main()
  44 {
  45     my_tuple t;
  46
  47     field<int>(t) = -1;
  48     field<char const*>(t) = "text";
  49     field<bool>(t) = false;
  50
  51     std::cout
  52         << field<int>(t) << '\n'
  53         << field<char const*>(t) << '\n'
  54         << field<bool>(t) << '\n'
  55         ;
  56
  57     return 0;
  58 }