User manual

Chapter 12: Overview of ESS features for the S family 63
In the (rare) case that you wish to pass command line arguments to the starting S+6
process, set the variable inferior-Splus-args.
Note that R has some extremely useful command line arguments. For example, --
vanilla will ensure R starts up without loading in any init files. To enter a command line
argument, call R using a "prefix argument", by
C-u M-x R
and when ESS prompts for "Starting Args ? ", enter (for example):
--vanilla
Then that R process will be started up using R --vanilla. If you wish to always call R
with certain arguments, set the variable inferior-R-args accordingly.
If you have other versions of R or S-Plus available on the system, ESS is also able to start
those versions. How this exactly works depend on which OS you are using, as described in
the following paragraphs. The general principle, regardless of OS, is that ESS searches the
paths listed in the variable exec-path for R binaries. If ESS cannot find your R binaries,
on Unix you can change the unix environment variable PATH, as this variable is used to set
exec-path.
R on Unix systems: If you have "R-1.8.1" on your exec-path, it can be started using M-x
R-1.8.1. By default, ESS will find versions of R beginning "R-1" or "R-2". If your versions
of R are called other names, consider renaming them with a symbolic link or change the
variable ess-r-versions. To see which functions have been created for starting different
versions of R, type M-x R- and then hit [Tab]. These other versions of R can also be started
from the "ESS->Start Process->Other" menu.
R on Windows systems: If you have "rw1081" on your exec-path, it can be started
using M-x rw1081. By default, ESS will find versions of R located in directories parallel to
the version of R in your PATH. If your versions of R are called other names, you will need
to change the variable ess-rterm-versions. To see which functions have been created for
starting different versions of R, type M-x rw and then hit [Tab]. These other versions of R
can also be started from the "ESS->Start Process->Other" menu.
Once ESS has found these extra versions of R, it will then create a new function, called
M-x R-newest, which will call the newest version of R that it found. (ESS examines the
date in the first line of information from R --version to determine which is newest.)
S on Unix systems: If you have "Splus7" on your exec-path, it can be started using
M-x Splus7. By default, ESS will find all executables beginning "Splus" on your path. If
your versions of S are called other names, consider renaming them with a symbolic link or
change the variable ess-s-versions. To see which functions have been created for starting
different versions of Splus, type M-x Splus and then hit [Tab]. These other versions of Splus
can also be started from the "ESS->Start Process->Other" menu.
A second mechanism is also available for running other versions of Splus. The variable
ess-s-versions-list is a list of lists; each sublist should be of the form: (DEFUN-NAME
PATH ARGS). DEFUN-NAME is the name of the new emacs function you wish to create
to start the new S process; PATH is the full path to the version of S you want to run;
ARGS is an optional string of command-line arguments to pass to the S process. Here is
an example setting:
(setq ess-s-versions-list