Subject: bug#41185: highlight-regexp not working properly

From: Michael Heerdegen <[email-masked]>
Date: Tue, 12 May 2020 00:55:16 +0200

jan <[email-masked]> writes:

> Try to regexp-highlight particular preprocessor use:
>
> M-s h r def HALF_LJ[^^]+?# endif RET
>
> (the [^^] is because I want it to match multiline, and I don't expect
> any carets in the text, so I negate that to allow newline matches and
> make it lazy to pick out the shortest +?  It's sloppy but ok here)
>
> Does not highlight anything

Yes, thanks.

I can reproduce this.  I'm not a font-lock expert, but I suspect that
hi-lock doesn't support patterns matching multi-line text.  Font-lock
supports multi-line matching, but this needs some extra efforts to work,
and I don't think hi-lock is caring about this at all.

If this is correct, maybe this feature can be implemented, and until
then, this limitation should be explicitly documented.

Michael.