From: Alan Mackenzie <acm@muc.de>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: HELP, PLEASE! Syntax problem!
Date: Wed, 25 Nov 2009 20:30:39 +0000 [thread overview]
Message-ID: <20091125203039.GA4874@muc.de> (raw)
In-Reply-To: <jwvws1ehdsi.fsf-monnier+emacs@gnu.org>
Hi, Stefan!
On Wed, Nov 25, 2009 at 09:43:01AM -0500, Stefan Monnier wrote:
> > In the following fragment of code:
> > 1 int a = foo (
> > 2 1);
> > 3 #define X(A, B) \
> > 4 do { \
> > 5 printf (A, B); \
> > 6 } while (0)
> > 7 int a = foo (
> > 8 1);
> > , there is a C macro between lines 3 and 6. The syntax-table
> > properties here have been manipulated (see below). Putting point at
> > the "(" in L5 and doing C-M-n takes point to after ")" ON LINE 8.
> > Similar things happen with C-M-p, C-M-u from various places inside
> > the macro
> > Evidently, all syntactic properties inside the macro have been
> > suppressed. This is not wanted.
> The first problem is most likely that `syntax-table' is only special for
> text-properties, not for char-properties in general (i.e. when placed
> on an overlay, it has no effect).
Ah. OK, that's a shame, but life is like that sometimes. I'd assumed
that the special properties in text properties would be the same as in
overlays (modulo any which are specific to the mechanism).
> Of course, the real problem is that the syntax-table hacking you're
> doing here is just that: a hack.
We're hackers. ;-)
> Maybe another hack would have fewer shortcomings? E.g. maybe you
> could place a syntax-table property on the # that says "beginning of
> comment" and a matching "end of comment" on the newline that
> terminates line 6?
Wow! That's one of these "why didn't I think of that?" ideas. It's
much simpler and more effective than individually marking each
paren/brace/bracket. But the thing to do is to set a category property
value 'c-cpp-delimiter at the boundaries of each macro. All that I have
to do now is to give that symbol the syntax-table property value
"generic comment delimiter", and all these pesky parens vanish just like
that, like switching a (n old fashioned tungsten) light bulb off. ;-)
> Then again, our syntax-tables are too limited in their comment
> handling, so given that CC already uses most forms of comments, it'll
> be difficult to make sure that # only matches that particular comment
> ender and not just "any \n" or "*/", but maybe just marking the "\\\n"
> that get in the way as "punctuation" would solve it?
One or two little things to sort out, and c-parse-state will run like
greased lightning, like "this of a spade" (or something like that). To
appreciate why I'm doing this, download
<http://www.muc.de/~acm/AT91SAM9263_inc.h> and try scrolling around near
EOB. :-( My fix to this problem speeds up scrolling speed by an order
of magnitude in such ill-conditioned files.
> Stefan
--
Alan Mackenzie (Nuremberg, Germany).
next prev parent reply other threads:[~2009-11-25 20:30 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 12:58 HELP, PLEASE! Syntax problem! Alan Mackenzie
2009-11-25 14:43 ` Stefan Monnier
2009-11-25 20:30 ` Alan Mackenzie [this message]
2009-11-25 21:45 ` Stefan Monnier
2009-11-25 22:13 ` Alan Mackenzie
2009-11-26 0:12 ` Stephen J. Turnbull
2009-11-26 8:53 ` Alan Mackenzie
2009-11-26 15:48 ` Stephen J. Turnbull
2009-11-27 9:16 ` Alan Mackenzie
2009-11-27 9:56 ` David Kastrup
2009-11-27 10:44 ` Alan Mackenzie
2009-11-27 8:16 ` A Soare
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