Re: [css-counter-styles] position keywords in list-style

On Tue, Apr 15, 2014 at 8:51 AM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:
>
> On Thu, Apr 3, 2014 at 3:58 PM, Xidorn Quan <quanxunzhen@gmail.com> wrote:
> > So how can we keep the compatibility? It seems to be nearly impossible now
> > if new keyword could be introduced.
>
> So this still isn't resolved.  As currently written, between Counter
> Styles and V&U, a <counter-style-name> is allowed to be "inside", but
> then you can't specify it in 'list-style' due to the collision.
>
> David suggests that we could allow it, if we adopt rules similar to
> 'animation', where the 'animation-name' is taken as the first
> unrecognized keyword, or the last keyword if they're all recognized.
> I and Xidorn both think this is probably harmful to spread further, as
> it's hard to serialize correctly, and is somewhat hostile to future
> expansion.
>
> A third opinion comes from fantasai, which is that
> <counter-style-name> is assumed to often show up in a 'list-style'
> context, and so it should exclude the 'list-style' keywords as well at
> all times.  This also has compat problems, as it means that any
> keywords we introduce to any of list-style's longhands become
> disallowed, which could damage existing content.  I think this also
> shouldn't be used.
>
> Thoughts?

I found that both Gecko and WebKit/Blink have been using the behavior
suggested by David on animation. Though I think this behavior is
harmful, all three methods mentioned here are in fact equally harmful
for list-style. Whatever rule is applied, there will be a compat
problem when we want to introduce any keyword to the longhands,
because we have accepted position keywords to be put as the first
subvalue. Hence, for list-style, I think it might be acceptable to
follow the behavior UAs currently use to parse animation property, and
leave the potential problem there until we actually want to introduce
new keywords in the future.

- Xidorn

Received on Tuesday, 29 April 2014 13:03:01 UTC