That's pretty much exactly how I develop. I rarely type anything directly into the REPL, instead typing into the source file in emacs and then C-c C-c it over

That's pretty much exactly how I develop. I rarely type anything directly into the REPL, instead typing into the source file in emacs and then C-c C-c it over to the REPL for me. The advantage is that I get a canonical copy of the entire source code, whilst still having the ability to inspect and hotfix things through the REPL. If I then need to reboot the image or deploy to a new server, the entire source base should be completely stable and consistent. I often connect to production servers using Slime and fix little things like typos this way - then check the source into Github and have it permanently saved. It removes a lot of the stress of doing a full deployment each time you need to patch something!