nb::cast<std::string>() bad cast

[fraguada]

I have a typedef: typedef py::object BND_UUID; (I have other code to switch between pybind11 and nanobind, so py:: refers to whatever lib I am using)

In pybind11 I could cast to string with std::string s = pybind11::str(id);
I am trying to do the same in nanobind with: std::string s = nb::cast<std::string>(id);

This is my function:

ON_UUID Binding_to_ON_UUID(const BND_UUID& id)
{
#if defined(NANOBIND)
  std::string s = py::cast<std::string>(id);
#else
  std::string s = pybind11::str(id);
  
#endif
  return ON_UuidFromString(s.c_str());
}

But am getting RuntimeError: std::bad_cast

From my python test:

print(type(id))
print(str(id))

and I get

<class 'uuid.UUID'>
eb0f1086-9981-49eb-affc-03a760956070

Feels like I am missing something simple.

[wjakob]

You are likely missing an include for the type caster, please review the documentation.

[wjakob]

You are likely missing an include for the type caster, please review the documentation.

[fraguada]

I am including nanobind/stl/string.h

[fraguada]

I guess what I am missing is that the object is a uuid, not a string. Besides converting the uuid to a string, what would be the correct way to pass that uuid object from python straight to c++ without converting first?

[fraguada]

Since I am trying to pass in a uuid.UUID object, what I needed to do was:
std::string s = py::cast<std::string>(id.attr("hex"));