Creating getters and setters for ndarray fields of structs #465

I tried to write Python bindings for a struct containing ndarray type fields, but it does not compile: (rust-numpy v0.22.0)

use pyo3::prelude::*;
use pyo3::{pymodule, Bound, PyResult};
use numpy::ndarray::Array2;

#[pyclass(get_all, set_all)]
#[derive(Debug, Clone)]
pub struct Foo {
    vec: Array2<f64>,  
}

#[pymodule]
fn my_module(m: &Bound<'_, PyModule>) -> PyResult<()> {
    m.add_class::<Foo>()?;
    Ok(())
}

I read the existing discussions (this and this) and they suggests writing getters and setters manually for each field, which is unsatisfactory.

This currently greatly limits the ability to make existing APIs that contain ndarrays available to Python: We can only use free functions but not structs or classmethods.

Why is this limitation ? Could it be solved by simply implementing the IntoPy<Py<PyAny>> and FromPyObject traits for ndarray ?
I see that this is done for smallvec's and having smallvec's as fields just works as expected.

Note also that this feature is present in C++'s pybind11 (the getters return a read-only array).

I would greatly appreciate the ability to bind ndarray fields and automatically provide getters and setters in Python. This would allow to fully bind an existing Rust API to Python.
Thanks a lot!