Re: font-lock-keywords: matcher function not working

[Raffaele Ricciardi <rfflrccrd@gmail.com>]

On 29/06/13 04:35, Stefan Monnier wrote:
>> Thank you again, Stefan.  However, I still don't understand.
>
> Your function should search for the first occurrence of the thing you're
> looking for, between here and ^end and only if there isn't any should it
> return nil.
>
> Instead, your current function only checks whether "here" is a spot that
> matches the thing you're looking for.  Instead, when you find out that
> "here" is not a match, don't return nil: try to look further instead.
> This is typically done with a loop.
>
> In your case, I wouldn't use a function anyway: I'd just use a regexp
> like "^[^ \t]*(".

Thank you for your attention, Stefan.  Now I understand what the font lock
engine requires.

Following your suggestion, this snippet performs the desired highlighting:

(font-lock-add-keywords 'lisp-interaction-mode
                         '(
                           ("^[[:blank:]]*\\((\\)" 1 
'font-lock-warning-face)
                           ))

However, unless I restart `lisp-interaction-mode', no highlighting occurs,
neither it does if I just restart `font-lock-mode'.  Why is it so?  I 
was expecting
`font-lock-fontify-buffer' to apply the new rules.