Re: A problem in using font-lock-add-keywords

[Dmitry Gutov <dgutov@yandex.ru>]

source liu <sourceonly@gmail.com> writes:
> 1. about font-lock-add-keywords
> I'm new to elisp, and i want to add some keywords to a mode( say,
> c-mode), a list is below,
> (defvar my-list '("FIXME" "AND" "OR"))
>
>
> and I find some hint in emacs help  C-h f "font-lock-add-keywords"
>
> ========= reference from the buff of help ===========
>  (add-hook 'c-mode-hook
>   (lambda ()
>    (font-lock-add-keywords nil
>     '(("\\<\\(FIXME\\):" 1 font-lock-warning-face prepend)
>       ("\\<\\(and\\|or\\|not\\)\\>" .
>        font-lock-keyword-face)))))
> ==========================================
>
> i've tested it, it works, but when i change the expression of
> "\\<(FIXME\\):"  by (regexp-opt mylist t), it can't work.  does
> someone give me some hint where my problem is?

The problem is likely with quoting. You need to expand the `regexp-opt'
call:

(font-lock-add-keywords nil
 `((,(regexp-opt mylist t) 1 font-lock-warning-face prepend)
   ("\\<\\(and\\|or\\|not\\)\\>" . font-lock-keyword-face))

By the way, as long as you want to highlight the whole match, you can
use the group number 0 and no grouping.