#include <iostream>
#include <boost/fusion/mpl.hpp>
#include <boost/fusion/include/mpl.hpp>
#include <boost/fusion/container/set.hpp>
#include <boost/fusion/include/at_key.hpp>
#include <boost/fusion/include/as_set.hpp>
#include <boost/mpl/vector.hpp>
#include <boost/mpl/set.hpp>
#include <boost/mpl/front.hpp>
#include <boost/mpl/fold.hpp>
#include <boost/mpl/placeholders.hpp>
#include <boost/mpl/insert.hpp>
struct node_base
{
int get() {return 123;}
};
struct node_a : public node_base
{};
struct node_b : public node_base
{};
struct node_c : public node_base
{};
typedef boost::mpl::vector3<
::boost::mpl::vector1<node_a>
,::boost::mpl::vector1<node_b>
,::boost::mpl::vector1<node_c>
>::type nested_vec_type;
typedef ::boost::mpl::fold<
nested_vec_type
, ::boost::mpl::set<>
, ::boost::mpl::insert<
::boost::mpl::placeholders::_1
, ::boost::mpl::front<::boost::mpl::placeholders::_2>
>
>::type restored_set_type;
typedef ::boost::fusion::result_of::as_set<restored_set_type> restored_fusion_set;
restored_fusion_set my_restored_set;
int main()
{
std::cout << boost::fusion::at_key<node_a>(my_restored_set).get() << std::endl;
std::cout << boost::fusion::at_key<node_b>(my_restored_set).get() << std::endl;
std::cout << boost::fusion::at_key<node_c>(my_restored_set).get() << std::endl;
return 0;
}
error C2039: 'category' : is not a member of 'boost::fusion::result_of::as_set<Sequence>'
error C2039: 'type' : is not a member of 'boost::fusion::result_of::end<Sequence>'
error C2504: 'boost::fusion::extension::end_impl<Tag>::apply<Sequence>' : base class undefined
error C2039: 'type' : is not a member of 'boost::fusion::result_of::begin<Sequence>'
error C2504: 'boost::fusion::extension::begin_impl<Tag>::apply<Sequence>' : base class undefined
error C2065: 'type' : undeclared identifier
简单的mpl序列(例如::boost::mpl::vector< node_a, node_b, node_c >)到fusion序列的转换工作正常。 但是当我尝试将经过处理的复杂mpl序列(如嵌套的mpl向量)转换为fusion序列(通过result_of::as_set或as_vector)时,出现了编译时错误。
"restored_set_type"的打印输出为:
struct node_c
struct node_b
struct node_a
我发现它似乎丢失了一些类型信息,这使得它与简单的mpl序列:: boost :: mpl :: vector < node_c,node_b,node_a > 不同。
我有没有遗漏任何需要指定的内容,比如标签、大小等等?谢谢!