Is it possible to allow implicit conversion from Python lists to ndarray?

[Ahajha]

In porting some existing pybind11 code, it seems pybind11::array_t would accept a list (emphasis on seems, I did not write said code). I find myself having to provide a second version of everything taking an ndarray where I would also want to allow a list to be passed in. It's fine if this is the case, but is there a way of allowing such an implicit conversion?

[wjakob]

That's a bit more tricky in the case of nanobind because it has no dependence on NumPy for array_t. So it wouldn't be reasonable to first call np.array() and then convert from that. You would need a custom path that internally converts the list into a DLPack tensor and then passes that to the existing dlpack tensor interface.

I'm open to adding such a feature, but it's not high on my own priority list. Would you be interested in adding something like that?

[Ahajha]

Been working on other things (CPython package for Conan 2.0, which also unblocks a nanobind Conan package), but I think I can start giving this some attention again.

[jmalkin]

@Ahajha I don't think I know the internals of nanobind well enough to help, but I just ran into a situation where this addition would be quite useful.

[Ahajha]

That's good to hear, gives me a little bit more motivation to work on it. I'm probably a month or two until I really need it, but I'm working on it here and there. Hopefully soon I'll have a (very) rough draft that I can put into a PR.

[wojdyr]

I could use that as well. I wonder, is anyone looking into it currently?

[Ahajha]

I probably should have said something earlier, I am no longer working on the above project, and I unfortunately haven't had the time to work on this feature. So unless someone else is, I believe the answer is that nobody is working on this.