Mapping more complex C++ types

[archit120]

While trying to map the OpenCV Point type to a corresponding type on Julia a lot of boiler-plate code is required along with changes to array.hpp. I was hoping this could be streamlined and made a better-supported feature in CxxWrap.

template<typename T>
struct CxxPoint
{
  T x;
  T y;
};
namespace jlcxx
{
  template<typename T> struct IsMirroredType<cv::Point_<T>> : std::true_type {};

  template<typename T> struct static_type_mapping<cv::Point_<T>> { using type = CxxPoint<T>; };

  template<typename T>
  struct julia_type_factory<cv::Point_<T>>
  {
    static inline jl_datatype_t* julia_type()
    {
      return (jl_datatype_t*)apply_type((jl_value_t*)jlcxx::julia_type("Point"), jl_svec1(julia_base_type<T>()));
    }
  };

  template<typename T>
  struct ConvertToJulia<cv::Point_<T>, NoMappingTrait>
  {
    CxxPoint<T> operator()(const cv::Point_<T>& cpp_val) const
    {
      return *reinterpret_cast<const CxxPoint<T>*>(&cpp_val);
    }
  };
};

The changes in array.hpp is from

  ValueT& operator[](const std::size_t i)
  {
    if constexpr(std::is_same<julia_t, ValueT>::value)
    {
      return data()[i];
    }
    else
    {
      return *extract_pointer_nonull<ValueT>(data()[i]);
    }
  }

to

  ValueT& operator[](const std::size_t i) const
  {
    if constexpr(std::is_same<julia_t, ValueT>::value)
    {
      return data()[i];
    }
     else if constexpr(std::is_same<julia_t, static_julia_type<ValueT>>::value && !std::is_same<julia_t, WrappedCppPtr>::value) 
    {
      return *reinterpret_cast<ValueT*>(&data()[i]);
    }
    else
    {
      return *extract_pointer_nonull<ValueT>(data()[i]);
    }
  }

[barche]

Not sure you will still read this, but the array.hpp change is now merged into libcxxwrap-julia and will be in the next release.

[archit120]

Thanks for working on this! I did read this haha but I've absolutely zero memory of what I wanted here

…

On Wed, 13 Nov, 2024, 11:00 pm Bart Janssens, ***@***.***> wrote: Not sure you will still read this, but the array.hpp change is now merged into libcxxwrap-julia and will be in the next release. — Reply to this email directly, view it on GitHub <#260 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA5NR4SVDEK5KILN6ZZECP32ANSRDAVCNFSM6AAAAABRWWGGPGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDINZTHA3DKNBQG4> . You are receiving this because you authored the thread.Message ID: ***@***.***>