From: Arjan Bos <Arjan.Bos@nospam.ISeeYou.nl>
Subject: Re: font-lock function matcher sample
Date: Tue, 03 Aug 2004 20:09:42 +0200 [thread overview]
Message-ID: <ceokv1$ib$1@reader08.wxs.nl> (raw)
In-Reply-To: <jwv4qntcnqn.fsf-monnier+gnu.emacs.help@gnu.org>
Stefan Monnier wrote:
>>What I have currently is working correctly. First I find a word. If word,
>>limit and point are the same as the previous time the function was called,
>>I return `nil'.
>
>
> The fact that you need to compare with last search indicates that there's
> something fishy with your code.
>
>
>> (while (and (re-search-forward beatnik-font-matcher-regexp limit t)
>> (not (= (beatnik-last-word-score) score-match))))
>
>
> Here you lose the information about whether the search succeeded or failed
> which the source of your problems. I.e. if the search fails immediately
> (typically you've hit LIMIT) then (= (beatnik-last-word-score) score-match)
> will be true and your code will screw up.
>
> How about the code below instead:
>
> (defun beatnik-=-matcher-p (limit score-match)
> "Tries to find a word whose scrable score matches score-match.
> If such a word was found, t is returned."
> (let (found)
> (while (and (setq found (re-search-forward
> beatnik-font-matcher-regexp limit t))
> (/= (beatnik-last-word-score) score-match)))
> found))
>
This is almost what I intended. This sets `found' to `t' even when the
asked for scrabble score via (beatnik-last-word-score) isn't found. But
when I move the `and' into the `setq' it doesn't work, meaning that it
locks itself fontifying.
(defun beatnik-=-matcher-p (limit score-match)
"Tries to find a word whose scrable score matches score-match.
If such a word was found, t is returned."
(let (found)
;; doesn't work:
(while (and (setq found (re-search-forward
beatnik-font-matcher-regexp limit t))
(/= (beatnik-last-word-score) score-match)))
found))
So, unfortunately, I'm back to my kludge with the global variable that
keeps track of the last matched match.
>
>>Stephan and Alan, many thanks for helping me out. Maybe your comments
>>should find their way to the doc-string or the info pages?
>
>
> From what I can see, your problems had nothing to do understanding how
> font-lock works. But if you have a concrete suggestion for how to change
> the docstring, patches are welcome.
>
Well, what I really missed was a sample function. I think the one you
posted could well serve as a template. The info page
((elisp)Search-based Fontification.) had the needed input and output for
the defun, but the doc-string for `font-lock-defaults' had neither.
Maybe it could point to the info page?
Although the info page contains all the needed info, I can understand it
now in hindsight, but the thing about `match-data' /was/ quite confusing
for me.
And the biggest nuisance in figuring this out was that emacs crashed a
lot when getting things wrong in the defun. It gave lots of `malloc'
errors and `double free' errors. Which is, of course, not a pretty way
to cancel fontifying ;-) .
--
--
If you really want to contact me, then replace the "I see you" text by
its three letter accronym, hetnet.
Fabricate Diem PVNC, Motto of the Night Watch -- Terry Pratchett
next prev parent reply other threads:[~2004-08-03 18:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-07-17 21:08 font-lock function matcher sample Arjan Bos
2004-07-25 8:26 ` Alan Mackenzie
2004-07-25 19:55 ` Arjan Bos
2004-07-26 20:59 ` Stefan Monnier
2004-07-26 21:00 ` Stefan Monnier
2004-07-27 18:12 ` Arjan Bos
2004-07-27 18:36 ` Stefan Monnier
2004-08-03 18:09 ` Arjan Bos [this message]
2004-08-03 18:39 ` Stefan Monnier
2004-08-04 18:56 ` Arjan Bos
2004-08-04 19:48 ` Stefan Monnier
2004-08-04 20:00 ` Arjan Bos
2004-08-04 20:08 ` Stefan Monnier
2004-08-05 19:16 ` Arjan Bos
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