GNU Info

(efaq)Turning on syntax highlighting

---

Next: Scrolling only one line Prev: Deleting menus and menu options Up: Common requests

---

Enter node , (file) or (file)node

How do I turn on syntax highlighting?
=====================================

   `font-lock-mode' is the standard way to have Emacs perform syntax
highlighting in the current buffer.  With `font-lock-mode' turned on,
different types of text will appear in different colors.  For instance,
if you turn on `font-lock-mode' in a programming mode, variables will
appear in one face, keywords in a second, and comments in a third.

   Earlier versions of Emacs supported hilit19, a similar package.  Use
of hilit19 is now considered non-standard, although `hilit19.el' comes
with the stock Emacs distribution.  It is no longer maintained.

   To turn `font-lock-mode' on within an existing buffer, use `M-x
font-lock-mode <RET>'.

   To automatically invoke `font-lock-mode' when a particular major
mode is invoked, set the major mode's hook.  For example, to fontify all
`c-mode' buffers, add the following to your `.emacs' file:

     (add-hook 'c-mode-hook 'turn-on-font-lock)

   To automatically invoke `font-lock-mode' for all major modes, you
can turn on `global-font-lock-mode' by including the following line in
your `.emacs' file:

     (global-font-lock-mode 1)

This instructs Emacs to turn on font-lock mode in those buffers for
which a font-lock mode definition has been provided (in the variable
`font-lock-global-modes').  If you edit a file in `pie-ala-mode', and
no font-lock definitions have been provided for `pie-ala' files, then
the above setting will have no effect on that particular buffer.

   Highlighting a buffer with `font-lock-mode' can take quite a while,
and cause an annoying delay in display, so several features exist to
work around this.

   In Emacs 21 and later, turning on `font-lock-mode' automatically
activates the new "Just-In-Time fontification" provided by
`jit-lock-mode'.  `jit-lock-mode' defers the fontification of portions
of buffer until you actually need to see them, and can also fontify
while Emacs is idle.  This makes display of the visible portion of a
buffer almost instantaneous.  For details about customizing
`jit-lock-mode', type `C-h f jit-lock-mode <RET>'.

   In versions of Emacs before 21, different levels of decoration are
available, from slight to gaudy.  More decoration means you need to wait
more time for a buffer to be fontified (or a faster machine).  To
control how decorated your buffers should become, set the value of
`font-lock-maximum-decoration' in your `.emacs' file, with a `nil'
value indicating default (usually minimum) decoration, and a `t' value
indicating the maximum decoration.  For the gaudiest possible look,
then, include the line

     (setq font-lock-maximum-decoration t)

in your `.emacs' file.  You can also set this variable such that
different modes are highlighted in a different ways; for more
information, see the documentation for `font-lock-maximum-decoration'
with `C-h v' (or `M-x describe-variable <RET>').

   You might also want to investigate `fast-lock-mode' and
`lazy-lock-mode', versions of `font-lock-mode' that speed up
highlighting.  These are the alternatives for `jit-lock-mode' in
versions of Emacs before 21.1.  The advantage of `lazy-lock-mode' is
that it only fontifies buffers when certain conditions are met, such as
after a certain amount of idle time, or after you have finished
scrolling through text.  See the documentation for `lazy-lock-mode' by
typing `C-h f `lazy-lock-mode'' (`M-x describe-function <RET>
lazy-lock-mode <RET>').

   Also see the documentation for the function `font-lock-mode',
available by typing `C-h f font-lock-mode' (`M-x describe-function
<RET> font-lock-mode <RET>').

   For more information on font-lock mode, take a look at the
`font-lock-mode' FAQ, maintained by Jari Aalto
<jari.aalto@ntc.nokia.com> at

   `ftp://cs.uta.fi/pub/ssjaaa/ema-font.gui'

   To print buffers with the faces (i.e., colors and fonts) intact, use
`M-x ps-print-buffer-with-faces' or `M-x ps-print-region-with-faces'.
You will need a way to send text to a PostScript printer, or a
PostScript interpreter such as Ghostscript; consult the documentation
of the variables `ps-printer-name', `ps-lpr-command', and
`ps-lpr-switches' for more details.