TinnR for Mac

In complement to Prof. Ripley's answer, here are a few tracks:

- Emacs/ESS, of course, and AquaMacs/ESS,
- JGR has a decent but simple R code editor; same for the default
R.app/R64.app,
- Eclipse/StatEt is and IDE (thus a little bit more complex than a simple
code editor),
- SciViews-K is another IDE compatible with Mac. It can also be used as a
code editor and it is very close to Tinn-R in term of functionnalities,
- TextWrangler (free) and BBEdit can be tweeked to syntax highlight R code
and submit code to R using AppleScript,
- TextMate has now a large palette of R-specific tools, thanks to active
contributors,
- jEdit; look for the Orchestra project for an impressive suite of R-aware
additions to jEdit,

There are certainly a couple of other options around, but you may be happy
with one of these.
Best,

Philippe Grosjean