About `No Python class registered for C++ class`,throw errors.

[shelllet]

class Strs {
std::vector<Str> m_cc;

public:
   ...
   Str [](int offset) { return m_cc[offset];}
   ...
};

class Str{};

struct StrToPython
{
  static PyObject* convert(const Str& b)
  {
      ...
  }
};

BOOST_PYTHON_MODULE(pytype_function_ext)
{
  class_<Strs >("Strs") ;

  to_python_converter< Str , StrToPython>();
}

test code

py::object list(Strs());

py::object s1 = list[0];// (1), throw "No Python class registered for C++ class Str"

py::object s2(Str()) // ok！it's call StrToPython::convert.

becuase to_python_converter does't set m_class_object value. so (1) throw errors.

how to resolve this problem?

[shelllet]

By default indexed elements are returned by proxy. disabled by supplying true in the NoProxy template parameter.