[PeCaN]

I don't consider Common Lisp “more dynamic” than Python; at least in that you modify code at runtime and such. Frequently Common Lisp code is not particularly dynamic, because you can get the same level of expressiveness without relying on mucking around with magic at runtime.

Also SBCL only generates really fast code if you use a lot of type hints and (optimize (speed 3) (safety 0)). That said, when you do, it's really fast.

[lispm]

Typically Common Lisp and its implementations provides a wide range of performance options. It's not limited to the model of some more primitive language runtimes, which provide only two modes (simplified): slow if implemented in the language, fast if it runs mostly in its runtime and library functions written in C. There are Common Lisp implementations which follow this model, too. But there are also many which have sophisticated runtimes with optimizing native code compilers.

To get to really fast code in Common Lisp one needs to write relatively low-level code with type declarations, optimization hints, low-level operators etc.

There is a part of Common Lisp which is as dynamic (more?) as Python: everything written in CLOS (multi-dispatch, multi-methods, method-combinations, ...) and expecially when using the CLOS MOP. Is it slower or faster than comparable Python code? I have no idea and I haven't seen any interesting benchmarks. The amount of CLOS use depends on the implementations. Some implementations have a lot of their library code and also much of the language itself (everything IO, error handling, ...) written using CLOS.

[lokedhs]

I have written plenty of heavily CLOS-based code that is still very fast. I doubt that Python could come close in performance.

I think it would be an interesting exercise to do some benchmarks to get some actual data behind both of our guesses.

As I am not a very experienced Python developer, would you be interested in writing some test code that is representative of typical Python code, and I'd be happy to port it over to CLOS and so that we can run some benchmarks?

I think such results would be of interest to the HN audience.