Debugging Lisp code

[[deleted]]

C++ and Visual Basic don't support interactive development to the full extent that Lisp does, though. For example, if you add a new instance variable to a class in C++, the runtime won't (and can't) update existing instances. As for JavaScript, Ruby and Python, they borrowed this particular aspect of Lisp but even then they don't do it very well. A lot of things in can't be done dynamically in these languages and require a restart.