#include <jsoncons/json_type_traits.hpp>json_type_traits defines a compile time template based interface for conversion between a basic_json value
and a value of some other type. json_type_traits implementations must specialize this traits class:
template <class Json, class T, class Enable=void>
struct json_type_traits
{
using allocator_type = Json::allocator_type;
static constexpr bool is(const Json&) noexcept;
static T as(const Json&);
static Json to_json(const T& val);
static Json to_json(const T& val, const allocator_type& alloc);
};The function json_type_traits<Json,T>::is(const Json& j) indictates whether j satisfies
the requirements of type T. This function supports the type selection strategy when
converting a Json value to the proper derived class in the polymorphic case, and
when converting a Json value to the proper alternative type in the variant case.
The function json_type_traits<Json,T>::as(const Json& j) tries to convert j
to a value of type T.
The functions json_type_traits<Json,T>::to_json(const T& val) and
json_type_traits<Json,T>::to_json(const T& val, const allocator_type& alloc)
try to convert val into a Json value.
jsoncons includes specializiations for most types in the standard library.
And it includes convenience macros that make specializing json_type_traits for your own types easier.