Selectors Level 4 selectors fail to parse

[timmywil]

These Level 4 Selectors currently fail to parse and will be considered valid some time in the future. I may have missed some, but I went through the spec and I think these are all of them.

/* http://dev.w3.org/csswg/selectors4/#column-combinator */
col.selected || td {}
/* http://dev.w3.org/csswg/selectors4/#idref-combinators */
label:matches(:hover, :focus) /for/ input,
label:matches(:hover, :focus):not([for]) input {}
/* http://dev.w3.org/csswg/selectors4/#subject */
!ol > li:only-child {}
/* http://dev.w3.org/csswg/selectors4/#attrnmsp */
@namespace foo "http://www.example.com";
[foo|att=val] { color: blue }
[*|att] { color: yellow }
[|att] { color: green }

[lukeapage]

which are implemented by browsers?

attributes I implemented in 1.4.0 beta the others we have said we will support when the spec is stable enough that it is unlikely to change and that it is implemented by 1 (ore preferably more) browsers

[timmywil]

Nice! I didn't know you had implemented attr namespaces already. AFAIK, none of these are supported yet except in experimental environments (for instance, Chrome with certain flags). I will be demonstrating these selectors in a presentation, but there probably aren't a lot of people in my position. Mostly, I figured it would be helpful for this repo to have a list for when they are implemented.

For what it's worth, the syntax for the subject selector could very well change, but the rest will probably be in the final draft.

[jonschlinkert]

Helpful to have the list, thank you. @timmywil if you're satisfied with the answer you can close the issue. Feel free to keep it open or continue the discussion here.

[lukeapage]

related to #550

lets leave it open... the time when we need to support them is approaching - if chrome and mozilla implement via flags and people are making software for 6 months time or libraries etc then they might like to start using them.

[jonschlinkert]

👍 would love to see these features supported.

[TedDriggs]

It also chokes on the grid row declaration syntax (see http://msdn.microsoft.com/en-us/library/windows/apps/hh466350.aspx for more)

-ms-grid-rows: 10px (250px 10px)[4];

[matthew-dean]

Three years later it doesn't appear that CSS Selectors Level 4 is any closer to exiting an editor's draft, and a few things have changed in the syntax in that time. (See: https://drafts.csswg.org/selectors-4/) Implementing parsing support is risky until it's in CR status. Closing this. Re-open a new issue once it reaches the stage of implementation.