: ''MATCH-ANCHORED should be of the form:
 (MATCHER PRE-MATCH-FORM POST-MATCH-FORM MATCH-HIGHLIGHT ...)
where MATCHER is a regexp to search for or the function name to call to make
the search, as for MATCH-HIGHLIGHT above, but with one exception; see below.
PRE-MATCH-FORM and POST-MATCH-FORM are evaluated before the first, and after
the last, instance MATCH-ANCHORED's MATCHER is used.  Therefore they can be
used to initialize before, and cleanup after, MATCHER is used.  Typically,
PRE-MATCH-FORM is used to move to some position relative to the original
MATCHER, before starting with MATCH-ANCHORED's MATCHER.  POST-MATCH-FORM might
be used to move back, before resuming with MATCH-ANCHORED's parent's MATCHER."
: -- Docstring from Hell (`font-lock-keywords')

You can find examples of font-lock expressions in AddKeywords and
GenericMode.

Every Element has one of the following forms:

; (REGEXP . FACE): Highlight REGEXP with FACE
; (REGEXP N FACE): Highlight group N in REGEXP with FACE
; (REGEXP (N1 FACE1) (N2 FACE2) (N3 FACE3) ...): Highlight group Ni in REGEXP with FACEi

Here is an example for elisp. Assume you want to highlight the expression
that explicitly loops over a list.  If you never want to break out of
the loop, or if you are using the CommonLisp package, you might use
dolist.  If not, however, it might look something like this:
<pre>
    (while lst
      (setq item (car lst)
            lst (cdr lst))
      ...
</pre>
We now want to highlight "item", and the three following lst instances
within the setq.  The following uses a long and complex regexp built
using the ReBuilder.

Note that \\( and \\) do the grouping, and that \\sw matches a word
character, and \\s_ matches a symbol character.  Thus,
\\(\\sw\\|\\s_\\)+ matches a variable name.  [ \t\n]* matches
whitespace including newlines.
<pre>
    (font-lock-add-keywords 'emacs-lisp-mode
	 '(("\\(\\(\\sw\\|\\s_\\)+\\)[ \t\n]*(car[ \t\n]*\\(\\(\\sw\\|\\s_\\)+\\)[ \t\n]*)[ \t\n]*\\(\\3\\)[ \t\n]*(cdr[ \t\n]*\\(\\3\\)[ \t\n]*)"
	    (1 'font-lock-variable-name-face)
	    (3 'font-lock-keyword-face)
	    (5 'font-lock-keyword-face)
	    (6 'font-lock-keyword-face))))
</pre>
----
CategoryFaces