Re: font-lock function matcher sample

[Arjan Bos]

Alan Mackenzie wrote:
> Arjan Bos <Arjan.Bos@nospam.iseeyou.nl> wrote on Sat, 17 Jul 2004
> 23:08:59 +0200:
>
> The font-lock function matcher wasn't (and possibly still isn't) fully
> documented in the elisp manual.  The following may be helpful:
>
>      When FUNCTION is called, it receives one argument, the limit of the
>      search.  Its search should start at point and not extend beyond the
>      limit.  FUNCTION should return non-`nil' if it succeeds, and set the
>      match data to describe the match that was found.  FUNCTION will be
>      called repeatedly with the same limit, and with point where the
>      previous invocation left it, until it fails.  It need not reset
>      point to a sensible value on failure.
Yeah, I found that passage. It was useful, up to a point. What I have 
now, works slightly better. I found out that I need to find words and 
calculate their scrabble-score.
Is it true then that I need to keep on searching forward until I find a 
word whose scrabble score matches 6 (or until I reach limit)? If so, I'm 
having trouble when point is at (- limit 1). When that's the case, the 
matcher function is called repeatedly without stopping.

> > I'm looking for a way to fontify words accoriding to their scrabble
> > score. So if a word would score 6 points in american scrabble, it
> > should get a certain font-locking.
>
>
> > Currently, I have the following elisp, but it does not work.
>
>
> Have you discovered the joys of edebug, yet?  If not, I thoroughly
> recommend you to invest a few hours learning it.  For example, put point
> inside `scrabble-6-matcher' and do C-u C-M-x to instrument it for edebug.
Normally I call M-x edebug-defun. How is this different?

> Then call the function directly with M-: (scrabble-6-matcher 200).
> Enjoy!
>
> A hint: if you're going to be using edebug within "live" font-lock
> routines, do this first:  M-: (setq font-lock-support-mode nil).
> Otherwise the jit-lock timer routine will kick in 3 seconds after you've
> starting looking at your function, destroying your concentration and
> peace of mind.
I tried it without the (setq ...) It didn't destroy anything. In fact, 
it didn't do anything at all. Although, come to think of it, I got a few 
malloc error messages from emacs in my console. But maybe that is 
because I'm using a cvs emacs from a week ago.

> As for locking the system, I suspect you've got into an infinite loop
> with your regular expression: (re-search-forward "\\([a-z]\\)*" limit t).
> This regexp will match any sequence of lower case letters, including an
> empty one.  ;-(.  Probably you really want something more like
> "\\([a-z]\\)+".  Then ask yourself whether you really want the "+"
> _outside_ the grouping parentheses.  ;-)

Thanks, currently I'm having a bit more success with "\\<\\(.+?\\)\\>

> Have fun!
Thanks! This /is/ fun! It's my summer holiday project. Done when I do 
not have to decorate my house (you know how spouses are ;-) )

Arjan

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