Texinfo provides more than a dozen definition commands, all of which are described in this section.
The definition commands automatically enter the name of the entity in
the appropriate index: for example, @deffn, @defun,
and @defmac enter function names in the index of functions;
@defvr and @defvar enter variable names in the index
of variables.
Although the examples that follow mostly illustrate Lisp, the commands can be used for other programming languages.