Rust struct into PyObject in rust-cpython

Question

I am using rust-cpython to write functions in Rust that is callable in Python.

I have an existing struct that is used as an output. How to I make this into a PyObject that rust-cpython can understand?

My struct looks like this:

struct Block {
    start: i32,
    stop: i32,
}

Answer 1

My compilation error said I needed to implement the ToPyObject trait on my struct. To represent my struct in one of the PyObject types, I decided to use a PyDict.

I looked at how rust-cpython does it for HashMap and I just copied it over.

impl ToPyObject for Block {
    type ObjectType = PyDict;

    fn to_py_object(&self, py: Python) -> PyDict {
        let dict = PyDict::new(py);
        dict.set_item(py, "start", self.start).unwrap();
        dict.set_item(py, "stop", self.stop).unwrap();

        dict
    }
}

This is kind of a hack but it allows me to pass data with named fields as keys.