2) Need "speed" - write that part in C.)

That's not so easy. Interfacing Python and C code is also incredibly hard, and no one true way exists.

>That's not so easy. Interfacing Python and C code is also incredibly hard, and no one true way exists.

Can you elaborate on this. I've worked on python C extensions (just minor updates and fixes, I've never been the one to write significant chunks of it), and it seems like interfacing python with C is pretty straight forward.

If you use the CPython C API it's easy - but you also bind yourself closely to CPython. If you know performance is going to be important it's probably better to bite the bullet and use PyPy - which means you have to use the somewhat cruder cffi to interface with C code.

I've done it numerous times over the last several years and while it's probably not trivial, it's definitely not hard. If you're looking for a "one true way", it's Python's C API.

It might be incredibly hard if you do not know C.