It looks like you need to copy your D array to a newly-allocated Numpy ndarray before you can pass it to Python. So there's no binary PyArrayObject interoperability between D & Python (right?). Copying large N-D arrays all the time sounds slow...

(That Matplotlib example uses the function `d_to_python_numpy_ndarray` in the PyD project, which I found defined here: https://github.com/ariovistus/pyd/blob/master/infrastructure... . It clearly allocates a new Numpy array: https://github.com/ariovistus/pyd/blob/master/infrastructure... )

Also, I couldn't find any examples of invoking D functions from Python. In fact, I could only find mentions on the D mailing list of people reporting that they couldn't get it to work: http://forum.dlang.org/post/rdhrvzhhwxgfyxzjevfu@forum.dlang...

By compiling (transpiling) to C, Nim really does have an unfair advantage in the interoperability challenge...