[CPops]

It seems as if every single key press, whether or not it affects the output (for example, writing in a comment or hitting enter to reorganize and space out code) causes every single function to be evaluated again.

You can test this out by adding something like this...

(time (+ 1 1))

...and start typing in a comment on a new line and seeing how the elapsed time that is outputted changes on every single key press. Performance optimizations are probably not as important right now, but that's something that can be improved.

Still, as a basic test of the concept, it looks pretty interesting overall and I can see myself using this. As long as the idea is sound, everything else can be improved over time. Keep it up!