User manual

Chapter 1: Introduction to ESS 18
a consistent user interface within emacs, regardless of the details of which programming
language is being edited, or process being run.
Some commands, such as M-x R can accept an optional ‘prefix’ argument. To specify the
prefix argument, you would type C-u before giving the command. e.g. If you type C-u M-x
R, you will be asked for command line options that you wish to invoke the R process with.
Emacs is often referred to as a ‘self-documenting’ text editor. This applies to ESS in two
ways. First, limited documentation about each ESS command can be obtained by typing
C-h f. For example, if you type C-h f ess-eval-region, documentation for that command
will appear in a separate *Help* buffer. Second, a complete list of keybindings that are
available in each ESS mode and brief description of that mode is available by typing C-h m
within an ESS buffer.
Emacs is a versatile editor written in both C and lisp; ESS is written in the Emacs
lisp dialect (termed ‘elisp’) and thus benefits from the flexible nature of lisp. In particular,
many aspects of ESS behaviour can be changed by suitable customization of lisp variables.
This manual mentions some of the most frequent variables. A full list of them however is
available by using the Custom facility within emacs. (Type M-x customize-group RET ess
RET to get started.) Appendix A [Customization], page 82 provides details of common 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.