python type for std::array

[vnghia]

I think it is good if we could add a caster for std::array, we already have std::vector so I think it won't be too hard. For my use case, I have some constexpr std::array that I want to expose to python without copying it to std::vector beforehand. I can send a PR if you think this is a good idea. Thank you very much.

[vnghia]

It will be just as simple as:

template <typename Type, size_t N>
struct nb::detail::type_caster<std::array<Type, N>>
    : nb::detail::list_caster<std::array<Type, N>, Type> {};

[wjakob]

Could you submit a PR with tests? In that case, I would merge it. Thanks!

[vnghia]

I realized that we can not cast from python list to std::array because the size has to be known at compile time. I am thinking of overriding the from_python of list_caster and return false or writing another caster entirely. What do you think ?

[vnghia]

or we could change this line:

nanobind/include/nanobind/stl/detail/nb_list.h

Line 37 in d9d0380

value.push_back(((Caster &&) caster).operator cast_t<Entry &&>());

to something like value[i] = ... and discard the rest if the list is longer or leave unintialized if the list is shoter than N.

[wjakob]

(Marking as answered since a type caster was added in the meantime)