Re: [css21] NUMBER, PERCENTAGE, DIMENSION tokens and signs

On Thu, May 10, 2012 at 10:26 AM, Kang-Hao (Kenny) Lu
<kennyluck@csail.mit.edu> wrote:
> (12/04/24 6:13), Tab Atkins Jr. wrote:
>> We propose amending the Core Grammar to make the + and - part of the
>> "num" production.  This shouldn't have any effect on real pages - we
>> highly doubt that any page has actually put a comment between a
>> negative sign and the number.
>
> I'd like to note that if we change this but not the grammar for calc(),
> it means that calc(1em + -1em) becomes conforming according to the
> grammar. Perhaps it isn't a bid deal because the implementations that
> ship already (IE9 and Firefox4+) already support this.

That calc expression should be conforming.

The calc() grammar has to be adjusted anyway, because it's currently
*correctly* including a manual +/- in the "unit" production.  We need
to remove that.

> But the next question is whether we want to change Selectors 3 as it
> explicitly forbids :nth(1n + -1) and the like.

The nth grammar is broken anyway (noted in a recent thread).  When we
rewrite the parsing for it, we'll just need to figure out what's sane
based on implementations.

~TJ

Received on Thursday, 10 May 2012 11:50:53 UTC