I do use REPL-driven development even for Python. (And why not? Like Norvig says, Python is basically lisp with traditional syntax.) > How could you ever know

I do use REPL-driven development even for Python. (And why not? Like Norvig says, Python is basically lisp with traditional syntax.) > How could you ever know things would actually work?! Eventually you would run the project from beginning to end to make sure it works. REPL just allows you to by-pass that during development for rapid feedback. If the project takes 2-3 seconds to boot, we are talking about a difference of getting feedback in milliseconds vs several seconds - which makes a huge qualitative difference in developer workflow. The point is precisely that you do NOT have to run it from beginning on every invocation. Doing it once in a while is enough.