W3C home > Mailing lists > Public > www-style@w3.org > August 2012

Re: [Syntax Level 3]

From: L. David Baron <dbaron@dbaron.org>
Date: Tue, 28 Aug 2012 14:36:25 -0700
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: Brian Kardell <bkardell@gmail.com>, fantasai <fantasai.lists@inkedblade.net>, "www-style@w3.org" <www-style@w3.org>
Message-ID: <20120828213625.GA15171@crum.dbaron.org>
On Tuesday 2012-08-28 13:38 -0700, Tab Atkins Jr. wrote:
> On Tue, Aug 28, 2012 at 1:21 PM, L. David Baron <dbaron@dbaron.org> wrote:
> > On Tuesday 2012-08-28 12:37 -0700, Tab Atkins Jr. wrote:
> >> The point is that, as currently implemented, whenever I see a ! in a
> >> rule, I need to push it into a substack, along with all subsequent
> >> whitespace and comment tokens, until I see a token that's neither
> >> whitespace nor a comment.  If it's an IDENT(important), I throw away
> >> the stack and make the declaration important.  If it's anything else,
> >> I insert the entire stack into the declaration's value.
> >>
> >> This isn't hard.  It is, however, inelegant and *useless*.  There is
> >> absolutely no reason to allow this, and it would simplify parsers the
> >> spec and parsers to disallow it.  There shouldn't be any compat impact
> >> to the change.
> >
> > Why should we allow ! within values?  It seems already somewhat
> > established as a delimiter.  Can't it just always end the value at
> > the !, and then make the thing after it make the declaration invalid
> > if it's something other than IDENT(important)?
> 
> I'm amused that your alternative to my syntax change is a larger
> syntax change. ^_^

It's not really a change, though.  It's merely a removal of a
reservation of syntax.

In other words, one way to look at the forward compatible grammar
is that it reserves large amounts of syntax for potential future
use.  What I'm proposing unreserves a tiny piece of it.  It doesn't
change the error handling behavior at all.

Also, I'm not proposing that we change the forward-compatible syntax
to treat things with multiple !s in a declaration or with things
other than important after the ! any differently from any other
invalid declaration.

I'm just proposing we don't allow ! inside the value of a variable
(which I think I'd proposed before), or inside the values of future
properties.

-David

-- 
𝄞   L. David Baron                         http://dbaron.org/   𝄂
𝄢   Mozilla                           http://www.mozilla.org/   𝄂
Received on Tuesday, 28 August 2012 21:36:51 GMT

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