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Re: [css3-syntax] First draft of parser section completed

From: Kang-Hao (Kenny) Lu <kennyluck@csail.mit.edu>
Date: Mon, 11 Jun 2012 07:50:49 +0800
Message-ID: <4FD532D9.8090709@csail.mit.edu>
To: WWW Style <www-style@w3.org>
CC: "Tab Atkins Jr." <jackalmage@gmail.com>
(12/06/09 14:45), Kang-Hao (Kenny) Lu wrote:
> (12/06/09 12:01), Kang-Hao (Kenny) Lu wrote:
>> 2. "At-rule-block" is incomplete, so it's hard to say if there's error
>> relating to at-rule error handling here or not.
> Mah, on a second read, I think I start to understand this, so...
> In "3.5.4. At-rule mode"
>   # close-paren token
>   # at-keyword token
>   #
>   # This is a parse error. Pop the current rule from the stack of open
>   # rules. Switch to the current rule's content mode.
> I think the spec probably meant to say "Switch to the
> next-block-or-statement error mode."

On a second thought, neither of these two matches IE9, Firefox13 and
Operal12alpha .

Test case:

data:text/html,<style>@media ),screen { body { background: green; }

and the variants using "]", "@ab", "<!--", "-->" in place of ")". WebKit
browsers don't implement the error handling even for, say, "@media
a+b,screen" so it's far from conforming anyway.

What will be needed is

  | This is a parse error. Append the current input token to the
  | prelude of the current rule and remain in this mode.

But then, I will wonder why we don't do the same for "style-rule mode"
and "consume a block". Failing early is going to limit our future. For
example, we could introduce

  (selector1, selector2) { }

in css4-selectors for media query-like error handling, but if "consume a
block" fails early when the "unused" things are encountered, it wouldn't
work like media queries.

Received on Sunday, 10 June 2012 23:51:16 UTC

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