Variant size test

variant_size_test.cpp

// Copyright Dave Abrahams 2012. Distributed under the Boost
// Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

# include <vector>
# include <map>
# include <string>
# include <boost/variant.hpp>

namespace tst {

using namespace boost;

struct null{};


namespace no_wrapper
{
  struct value;
  typedef std::map<std::string, value> object;
  typedef std::vector<value> array;

  typedef variant<
     null, std::string, double, object, array, bool
  > value_base;

  struct value : value_base
  {
    value() {};
    
    template <class T>
    value(T const& x) : value_base(x) {} // no move; I'm in C++03-land
  };
}

namespace wrapper
{
  struct value;
  typedef std::map<std::string, value> object;
  typedef std::vector<value> array;

  typedef variant<
      null, std::string, double,
      recursive_wrapper<object>,
      recursive_wrapper<array>,
      bool
  > value_base;

  struct value : value_base
  {
    value() {};
    
    template <class T>
    value(T const& x) : value_base(x) {} // no move; I'm in C++03-land

    value& operator=(value const& x) {
      value_base const& x_ = x;
      value_base::operator=(x_);
      return *this;
    }
  };
}

namespace easy {

  typedef make_recursive_variant<
      null, std::string, double,
      std::map<std::string, recursive_variant_>,
      std::vector<recursive_variant_>,
      bool
  >::type value;
  typedef std::map<std::string, value> object;
  typedef std::vector<value> array;
}
}

# include <iostream>
int main()
{
  tst::no_wrapper::array a1;
  tst::wrapper::array a2;
  tst::easy::array a3;
  tst::no_wrapper::object o1;
  tst::wrapper::object o2;
  tst::easy::object o3;
  tst::no_wrapper::value v1 = a1;
  tst::wrapper::value v2 = a2;
  tst::easy::value v3 = a3;
  std::cout << "size of objects: " <<  sizeof(o1) << ", " << sizeof(o2) << ", " << sizeof(o3) << std::endl;
  std::cout << "size of arrays: " <<  sizeof(a1) << ", " << sizeof(a2) << ", " << sizeof(a3) << std::endl;
  std::cout << "size of variants: " <<  sizeof(v1) << ", " << sizeof(v2) << ", " << sizeof(v3) << std::endl;
}