If you use Emacs to edit your LaTeX files, then you want to know about Local Variables. They are “comments” that you write at the end of a file, say in this example:
% Local variables:
% mode: latex
% TeX-master: "main.tex"
The purpose of local variables is to allow you to give Emacs extra customization when you load a file. In this example, we want Emacs to switch to latex mode and set the
TeX-master variable to “soda.tex”.
mode is actually a special variable controlling the major mode of the file. The
TeX-master variable is used by AUCTeX so that when you invoke LaTeX on the current buffer (Ctrl-C Ctrl-C), it will instead invoke LaTeX on the “master” file. This is crucial when you break the paper into multiple files and use
\input to string them together because this alleviates the need to switch to the master file before you invoke LaTeX.
There is also another way to specify local variables by putting them in the beginning of a file. Here is how our example would look like:
% -*- mode: latex; TeX-master: "main.tex"; -*-
There is also a special local “variable” call
eval. The value for that variable is simply evaluated as an expression, and hence it can actually be somewhat dangerous. Fortunately Emacs also provides
enable-local-eval to let you catch the
Happy TeXing in Emacs!