Travis Oliphant wrote:

Andrew Straw wrote:

...

On the one hand, I feel we should keep __array_struct__ behaving exactly as it is now. There's already lots of code that uses it, and it's tremendously useful despite (because of?) it's simplicity. For these of use cases, the __array_descr__ information has already proven unnecessary. I must say that I, and probably others, thought that __array_struct__ would be future-proof. Although the magnitude of the proposed change to add this information to the C-struct PyArrayInterface is minor, it still breaks code in the wild.

I don't see how it breaks any code in the wild to add an additional member to the C-struct. We could easily handle it in new code with a flag setting (like Python uses). The only possible problem is looking for it when it is not there.

Ahh, thanks for clarifying. Let me paraphrase to make sure I got it right: given a C-struct "inter" of type PyArrayInterface, if and only if ((inter.flags & HAS_ARRAY_DESCR) == HAS_ARRAY_DESCR) inter could safely be cast as PyArrayInterfaceWithArrayDescr and thus expose a new member. This does seem to avoid all the issues and maintain backwards compatibility. I guess the only potential complaint is that it's a little C trick which might be unpalatable to the core Python devs, but it doesn't seem egregious to me. If I do understand this issue, I'm +1 for the above scheme provided the core Python devs don't mind. Cheers! Andrew