Re: [css3-ui] Pseudo elements

> On 13 Nov 2014, at 19:45, Tantek Çelik <tantek@cs.stanford.edu> wrote:
> 
> On Thu, Nov 13, 2014 at 10:04 AM, Florian Rivoal <florian@rivoal.net> wrote:
>> css3-ui defines a few pseudo elements meant to style XFORMS in http://dev.w3.org/csswg/css-ui/#pseudo-elements, all marked at risk. During TPAC, a task was assigned to Bert (http://www.w3.org/Style/CSS/Tracker/actions/656) to ask Steven Pemberton and try find if there are any implementations. Steven suggested XSLTForms as the most likely candidate, but it does not implement these pseudos. Bert found one implementation: X-Smile (http://www.xsmiles.org/), but this is unmaintained since 2008.
>> 
>> Tantek, do you know of other implementations?
> 
> I do not.
> 
> 
>> If not, even though they seem quite well defined to me, given the apparent general lack of implementation interest and the status of XFORMS on the web, I suggest dropping this section from CSS3-UI.
> 
> Agreed and that was my plan once putting them at risk.


Hi Tantek,

Thanks for making the edit removing pseudo elements from css3-ui. I noticed that you kept the ::value and ::choices pseudo elements, citing applicability to HTML and mozilla's intent to implement[1].

For ::value, I agree it is is relevant for HTML, and even though the mozilla bug is pretty old, at least it shows some interest. At the same time, one intent to implement falls short of 2 implementations. I think you were right to keep it instead of deleting it, but I suggest moving it to the css-pseudo spec. It is a (the?) good home for pseudo elements, and isn't nearly as close as css-ui to trying to pass the CR exit criteria, so the lack of implementations isn't problematic. While we're at it, we should probably clarify if ::value, in combination with :placeholder-shown[2], can be used to style the placeholder, or it if only applies to the non placeholder value. I'd favour making :placeholder-shown::value select the placeholder.

::choices should probably be moved to css-pseudo as well if we decide to keep it, but I am more sceptical that we should. I don't know how much weight to put behind mozilla's intent to implement here, as it is a single comment, by you, in the bug about ::value. Also, the spec currently does not say which properties would apply in this pseudo. Finally, the second paragraph sounds a bit strange to me: radio buttons have actual elements that can be already be selected, so I am not sure why we'd need the pseudo to match them as well. Moreover, given that we have a :checked pseudo class [3] for the selected radio button, I don't think we should overload ::value to do this; the semantics are not a perfect match anyway, and this should really be done by a pseudo class, not a pseudo element. All in all, this seems like an underspecified feature with very limited interest from implementors; and I'd say it probably belongs in the wiki.

 - Florian

[1] https://bugzilla.mozilla.org/show_bug.cgi?id=648643
[2] http://dev.w3.org/csswg/selectors/#placeholder-shown-pseudo
[3] http://dev.w3.org/csswg/selectors/#checked

Received on Tuesday, 6 January 2015 00:51:32 UTC