Current Documentation by A.J. Rossini (rossini@stat.sc.edu) Department of Statistics University of South Carolina, USA. Original Documentation by David Smith (D.M.Smith@lancaster.ac.uk) Department of Mathematic and Statistics Lancaster University, UK Copyright © 1992, 1993, 1994, 1995 David M. Smith Copyright © 1996, 1997 A.J. Rossini.
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
The S and Splus packages provide sophisticated statistical and graphical routines for manipulating data. S-mode, the package on which ESS was based, provided a programming environment for data analysis and statistical programming, as well as an intelligent interface to the S process.
The ESS (:= Emacs Speaks Statistics) package is an extension of S-mode to provide a common, generic, and useful interface, through Emacs, to many statistical packages. It has currently been extended for R, XLisp-Stat, and SAS, with other statistical languages such as Stata, SPSS, and Fiasco slated for implementations in the future.
A bit of notation before we begin. Emacs refers to both
Emacs as distributed by the Free Software Foundation, as well as
XEmacs, which is a second GNU version of Emacs. The Emacs major
mode ESS[language] which is used for editing source for dialect
language, can take values S, SAS, or XLS,
for instance. The inferior process interface (the connection between
Emacs and the running process) referred to as interactive ESS
(iESS), is denoted in the modeline by ESS[dialect], where
dialect can take values S3, S4, S+3,
R, XLS, VST, SAS, as well as others.
Currently, the documentation contains many references to `S' where actually any supported (statistics) language is meant, i.e., `S' could also mean `XLisp-Stat' or `SAS'.
For exclusively interactive users of S, ESS provides a number of features to make life easier. There is an easy to use command history mechanism, including a quick prefix-search history. To reduce typing, command-line completion is provided for all S objects and "hot keys" are provided for common S function calls. Help files are easily accessible, and a paging mechanism is provided to view them. Finally, an incidental (but very useful) side-effect of ESS is that a transcript of your session is kept for later saving or editing.
No special knowledge of Emacs is necessary when using S interactively under ESS.
For those that use S in the typical edit--test--revise cycle when programming S functions, ESS provides for editing of S functions in Emacs edit buffers. Unlike the typical use of S where the editor is restarted every time an object is edited, ESS uses the current Emacs session for editing. In practical terms, this means that you can edit more than one function at once, and that the ESS process is still available for use while editing. Error checking is performed on functions loaded back into S, and a mechanism to jump directly to the error is provided. ESS also provides for maintaining text versions of your S functions in specified source directories.
S is a powerful system for manipulating and analyzing data, but its user interface -- particularly on Unix platforms -- leaves something to be desired. ESS is a package which is designed to make S easier to use.
ESS provides several features which make it easier to interact with the ESS process (i.e. enter commands and view the output). These include:
tcsh's facility for filenames; here it
also applies to object names and list components.
See section Completion of object names.
objects() and search().
See section Hot keys for common commands.
If you commonly create or modify S functions, you will have found the standard facilities for this (the `fix()' function, for example) severely limiting. Using S's standard features, one can only edit one function at a time, and you can't continue to use S while editing. ESS corrects these problems by introducing the following features:
Finally, ESS provides features for re-submitting commands from saved transcript files, including:
New user-visible features to ESS are documented in the `Doc/NEWS' file; all changes are listed in the `ChangeLog' file. Selected features new to recent versions of ESS are listed below; for changes to older version check the `Doc/NEWS' file. Planned features and bugs to fix can be found in the `Doc/TODO' file.
ESS is based on Olin Shivers' excellent comint package (which is supplied with version 19 of GNU Emacs). The original version of ESS (then known as `S-mode') was written by Doug Bates (bates@stat.wisc.edu) and Ed Kademan (kademan@stat.wisc.edu). Frank Ritter (ritter@psy.cmu.edu) then merged this version with his own S-mode mode to form `S.el' version 2.1.
Version 2.1 of `S.el' was then updated and expanded by David Smith to form version 3.4. This was then updated for Emacs 19 to create version 4. Most bugs have now been fixed (and several new ones introduced) and many new features have been added. Thanks must go to the many people who have helped with the development of the present version of ESS:
ess-eval-line-and-next-line are by Rod Ball.
The new version, ESS version 5, is being developed and currently maintained by
The latest (beta) versions are always available
http://franz.stat.wisc.edu/pub/ESS/
ftp://franz.stat.wisc.edu/pub/ESS/
The latest officially released version of S-mode is still available via WWW from:
Check the README file first to see which files you need.
Note that all new user-visible features to versions of ESS are documented in the `Doc/NEWS' file; all changes are listed in the `ChangeLog' file.
If ESS has already been installed on your system, the next chapter has details on how to get started using S under ESS.
If you need to install ESS, read section Installing ESS on your system for details on what needs to be done before proceeding to the next chapter.
section Customizing ESS provides details of user variables you can change to customize ESS to your taste, but it is recommended that you defer this section until you are more familiar with ESS.
Don't forget that this manual is not the only source of information about ESS. In particular, the mode-based online help (obtained by pressing C-h m when in the process buffer, edit buffer or help buffer) is quite useful. However the best source of information is, as always, experience -- try it out!
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