使用 boost fusion 获取结构名称
getting the structure name with boost fusion
使用 boost::fusion
可以迭代适应的结构并获取该结构的每个成员的名称。
有没有办法通过某种方式也检索结构的名称?
我想做的是:鉴于当前情况
namespace inner {
struct test_struct {
int a;
int b;
} }
BOOST_FUSION_ADAPT_STRUCT( inner::test_struct, a, b );
我想要一个函数 return "test_struct" (或 "inner::test_struct" )
我确实检查了包含 struct_size
和其他扩展名 类 的头文件[*],但我没有找到任何具有该目的的文件。
你知道有什么办法可以做到这一点吗?
[*] boost/fusion/adapted/struct/detail/extension.hpp
这不是一项功能。您可以通过检查预处理器的输出来查看它。
您可以看到 struct_member_name
扩展名,但结构名称没有这样的文字:
namespace boost {
namespace fusion {
namespace traits {
template <> struct tag_of<inner::test_struct> { typedef struct_tag type; };
template <> struct tag_of<inner::test_struct const> {
typedef struct_tag type;
};
} // namespace traits
namespace extension {
template <> struct access::struct_member<inner::test_struct, 0> {
struct deduced_attr_type {
static const inner::test_struct& obj;
typedef boost::type_of::remove_cv_ref_t<decltype(obj.a)> type;
};
typedef deduced_attr_type::type attribute_type;
typedef attribute_type type;
template <typename Seq> struct apply {
typedef typename add_reference<
typename mpl::eval_if<is_const<Seq>, add_const<attribute_type>,
mpl::identity<attribute_type>>::type>::type
type;
constexpr static type call(Seq& seq) { return seq.a; }
};
};
template <> struct struct_member_name<inner::test_struct, 0> {
typedef char const* type;
constexpr static type call() { return "a"; }
};
template <> struct access::struct_member<inner::test_struct, 1> {
struct deduced_attr_type {
static const inner::test_struct& obj;
typedef boost::type_of::remove_cv_ref_t<decltype(obj.b)> type;
};
typedef deduced_attr_type::type attribute_type;
typedef attribute_type type;
template <typename Seq> struct apply {
typedef typename add_reference<
typename mpl::eval_if<is_const<Seq>, add_const<attribute_type>,
mpl::identity<attribute_type>>::type>::type
type;
constexpr static type call(Seq& seq) { return seq.b; }
};
};
template <> struct struct_member_name<inner::test_struct, 1> {
typedef char const* type;
constexpr static type call() { return "b"; }
};
template <> struct struct_size<inner::test_struct> : mpl::int_<2> {};
template <> struct struct_is_view<inner::test_struct> : mpl::false_ {};
} // namespace extension
} // namespace fusion
namespace mpl {
template <typename> struct sequence_tag;
template <> struct sequence_tag<inner::test_struct> {
typedef fusion::fusion_sequence_tag type;
};
template <> struct sequence_tag<inner::test_struct const> {
typedef fusion::fusion_sequence_tag type;
};
} // namespace mpl
} // namespace boost
与往常一样,添加您自己的宏来获取额外信息可能并不难。参见例如 or Boost fusion sequence type and name identification for structs and class
使用 boost::fusion
可以迭代适应的结构并获取该结构的每个成员的名称。
有没有办法通过某种方式也检索结构的名称?
我想做的是:鉴于当前情况
namespace inner {
struct test_struct {
int a;
int b;
} }
BOOST_FUSION_ADAPT_STRUCT( inner::test_struct, a, b );
我想要一个函数 return "test_struct" (或 "inner::test_struct" )
我确实检查了包含 struct_size
和其他扩展名 类 的头文件[*],但我没有找到任何具有该目的的文件。
你知道有什么办法可以做到这一点吗?
[*] boost/fusion/adapted/struct/detail/extension.hpp
这不是一项功能。您可以通过检查预处理器的输出来查看它。
您可以看到 struct_member_name
扩展名,但结构名称没有这样的文字:
namespace boost {
namespace fusion {
namespace traits {
template <> struct tag_of<inner::test_struct> { typedef struct_tag type; };
template <> struct tag_of<inner::test_struct const> {
typedef struct_tag type;
};
} // namespace traits
namespace extension {
template <> struct access::struct_member<inner::test_struct, 0> {
struct deduced_attr_type {
static const inner::test_struct& obj;
typedef boost::type_of::remove_cv_ref_t<decltype(obj.a)> type;
};
typedef deduced_attr_type::type attribute_type;
typedef attribute_type type;
template <typename Seq> struct apply {
typedef typename add_reference<
typename mpl::eval_if<is_const<Seq>, add_const<attribute_type>,
mpl::identity<attribute_type>>::type>::type
type;
constexpr static type call(Seq& seq) { return seq.a; }
};
};
template <> struct struct_member_name<inner::test_struct, 0> {
typedef char const* type;
constexpr static type call() { return "a"; }
};
template <> struct access::struct_member<inner::test_struct, 1> {
struct deduced_attr_type {
static const inner::test_struct& obj;
typedef boost::type_of::remove_cv_ref_t<decltype(obj.b)> type;
};
typedef deduced_attr_type::type attribute_type;
typedef attribute_type type;
template <typename Seq> struct apply {
typedef typename add_reference<
typename mpl::eval_if<is_const<Seq>, add_const<attribute_type>,
mpl::identity<attribute_type>>::type>::type
type;
constexpr static type call(Seq& seq) { return seq.b; }
};
};
template <> struct struct_member_name<inner::test_struct, 1> {
typedef char const* type;
constexpr static type call() { return "b"; }
};
template <> struct struct_size<inner::test_struct> : mpl::int_<2> {};
template <> struct struct_is_view<inner::test_struct> : mpl::false_ {};
} // namespace extension
} // namespace fusion
namespace mpl {
template <typename> struct sequence_tag;
template <> struct sequence_tag<inner::test_struct> {
typedef fusion::fusion_sequence_tag type;
};
template <> struct sequence_tag<inner::test_struct const> {
typedef fusion::fusion_sequence_tag type;
};
} // namespace mpl
} // namespace boost
与往常一样,添加您自己的宏来获取额外信息可能并不难。参见例如