I would like to consider Python a common lisp alternative. But it's one or two orders of magnitude slower and is not really standardized. I think there is a lot more that's attractive than just macros.
What do you mean by this ?
And PyEvalFrameEx is the stuff of nightmares that can't be really fixed because it hardcoded spaghetti that, if rewritten, could subtly break python in myriad ways that would make 2->3 migration a cakewalk.
Oh, and there's no real test suite to verify if you didn't break something subtle in implementation.
While parsing Ruby code is well known to be problematic, there is a very good reason why Ruby can have interchangeable implementation while Python pretty much can't.