Function cast

tests/test_docs_advanced_cast_custom.cpp:34–37

C++ -> Python: convert `Point2D` to `tuple[float, float]`. The second and third arguments are used to indicate the return value policy and parent object (for return_value_policy::reference_internal) and are often ignored by custom casters. The return value should reflect the type hint specified by the second argument of `io_name`.

    // return_value_policy::reference_internal) and are often ignored by custom casters.
    // The return value should reflect the type hint specified by the second argument of `io_name`.
    static handle
    cast(const user_space::Point2D &number, return_value_policy /*policy*/, handle /*parent*/) {
        return py::make_tuple(number.x, number.y).release();
    }

    // Python -> C++: convert a `PyObject` into a `Point2D` and return false upon failure. The
    // second argument indicates whether implicit conversions should be allowed.