Suppose I want to make additions to a major mode's syntax highlighting, how would I do this without modifying the major mode's source code?
- Redefine variable in .emacs
- Define a minor mode with the changes
font-lock-add-keywords. See the Elisp manual, node Customizing Keywords.
The Elisp manual is your friend:
C-h i, then choose it. In the manual,
i is your friend. E.g.,
i font-lock TAB.