Convert to object

[mrzv]

I want to assign a class, exposed to Python through pybind11, to a module's attribute. This requires converting it to an object. To make things concrete, I want to use RAII pattern to initialize and finalize MPI whenever the module is imported. The code looks roughly like this:

struct environment
{
  environment()    { MPI_Init(0,0); }
  ~environment()   { MPI_Finalize(); }
};

py::class_<environment>(m, "environment")
  .def("__repr__", [](const environment&) { return "MPI Environment"; });

m.attr("env") = py::detail::type_caster<environment>::cast(new environment, py::return_value_policy::automatic, m.ptr());

This works, but it's the last line that bothers me. Is this really the right way to do this? Have I missed some cleaner way? Besides being verbose, having to access detail namespace seems wrong. I'm probably missing something, but if not, maybe it's worth adding clean support for this use-case?

[wjakob]

Does this work? m.attr("env") = py::cast(new environment);?

[mrzv]

Indeed it does. I simply couldn't find py::cast. My bad. Thanks for your help (and for the wonderful library).

[wjakob]

great to hear it's useful. I've added more information about casting to the documentation.