The wiki is a great resource: http://www.cliki.net/Development

Really for a good experience you just need something with Swank support and ability to highlight matching parens. Eclipse would even work, though I haven't tried any of the plugins for it. IDE features like introspecting values, breakpoints, tracing, profiling, stepping, recompiling are all part of the Common Lisp standard so you'll get them for free just by running the Lisp REPL in a terminal. What you use on top of that is really just making it more convenient to interact with the Lisp environment than typing everything in by hand. I like slimv with its auto-paren-infer stuff turned off (matching and rainbow parens are fine for me) but I've also just used a tool that uses two screen sessions to send data back and forth without using Swank (or even Lisp, I use it sometimes for Python but that's trickier because I can't just send a class to (re)define if I have newlines between methods and I can't casually change my namespace).

I wonder why there aren't more good IDEs for Lisp. Is it just because Emacs is already there? It seems like it would actually be easier to create an IDE for Lisp than for other languages. Parenthesis editing should be very simple, as should sending definitions to the running system... Is it more complicated than I think?

Yes, we have Vim and Atom plugins: https://github.com/CodyReichert/awesome-cl#text-editor-resou...

And [Portacle](https://shinmera.github.io/portacle/) is an Emacs shipped with SBCL, Slime and Git in a portable and multiplatform way, so it's straightforward to begin with.

Pretty much everyone I know that does lisp uses Emacs + SLIME.

:(

Also, from a _very_ quick test, it looks like Atom has ok support for SLIME.

Just grab the latest release from https://github.com/slime/slime/releases Install atom-slime and sbcl (something like brew install sbcl on osx) Point atom to the directory you extracted slime to and then hit packages > slime > start

vim + slimv is a pretty good combo, if you're used to vim. Also, although it won't give you the "full lisp experience", using something like parinfer or paredit in Atom will make editing lisp more pleasant.