I take it these "Interaction nets" won't be compilable from just any old python code? I can only imagine there are still some pretty heavy constraints around parallelism. Is the idea here that your python script would be SIMD?
The ultimate goal is indeed to compile any code to GPUs, but we can't change the logic of your program. It is just a bunch of sequential loops, there isn't much we can do about it! But you can still use a Python-like syntax to create highly parallel programs, specially if you like recursion or things like map, reduce, and working with trees/JSON in general.