Alternative to buffer protocol

[awni]

We are evaluating switching MLX from Pybind11 to Nanobind (ml-explore/mlx#839)

The nb::ndarray seems to be fine for constructing MLX arrays from e.g. incoming NumPy arrays. However, we use the buffer protocol to be able to do:

np.array(mlx_array)

However, nanobind does not have the same support for the buffer protocol. I am wondering if there is a recommended approach to achieve the same as above?

[wjakob]

Please see this part of the documentation: https://nanobind.readthedocs.io/en/latest/typeslots.html

You should be able to add custom slots recreate the pybind11 behavior if you truly want your object to expose the native buffer protocol. What I think would be much easier is to add an __array__ method to your class, which NumPy will accept as well.

[awni]

Yes I considered __array__ which works fine, but just for numpy. Instead I just reimplemented the buffer protocol as you suggested. It is not too bad actually.