[sswezey]

REPL-based development doesn't require typing directly into the REPL. It's usually a text editor side-by-side with the REPL. Most LISP IDEs have a command to send forms over to the REPL to be evaluated. In this manner, you develop your code iteratively with the REPL almost as if having a conversation with the REPL. You try a form, and if it doesn't work, you change and iterate, line by line of your code. Through this "conversation", you've gone from a single form, to an entire function that works, than a module. You build from the bottom up. There is no, code-compile-test cycle, it's always instantaneous. With some REPLs (like Common Lisp), you can even break from an exception, update your code and resume the code from the point before the exception. It's much more than the REPL most people are used to with Python or Ruby.