I suggest: do you find yourself often quitting the debugger and re-running the same test, the same task from the start? You can avoid that in CL. Just leave the

I suggest: do you find yourself often quitting the debugger and re-running the same test, the same task from the start? You can avoid that in CL. Just leave the debugger open, go to the buggy line ("v" on a stacktrace in Slime), fix the function, re-compile it on the fly (C-c C-c in Slime), come back to the debugger, resume the program from the stackframe you want, now it passes. If the first steps were taking 10 minutes, you just saved yourself some time. You don't need special needs for that, it's a fast workflow I use everyday. demo: https://www.youtube.com/watch?v=jBBS4FeY7XM https://www.youtube.com/watch?v=jBBS4FeY7XM debugging a complex stacktrace: Python VS CL: https://lisp-journey.gitlab.io/images/debugging-python-VS-lisp.png https://lisp-journey.gitlab.io/images/debugging-python-VS-li... Another important point: we debug everything while keeping the current state in memory (in the image). We don't have to re-create our test data. All the program state is kept live, until we restart the image.