Emacs mode for statistical programming and data analysis

 ESS ("Emacs Speaks Statistics") is a GNU Emacs and XEmacs mode for
 interactive statistical programming and data analysis. Languages
 supported are the S family (S 3/4, S-PLUS 3/4/5/6/7, and R), SAS,
 XLispStat, Stata, and BUGS.
 .
 ESS grew out of the desire for bug fixes and extensions to S-mode and
 SAS-mode as well as a consistent union of their features in one
 package.