[css-functions] Shouldn't the index of functions include `url()`?

[praveenpuglia]

I am looking at the CSS Indexes, Functions section and I realized the url() function isn't mentioned there. Is this deliberate or am I missing something?

Looking at this example it feels like it should be part of it.

[plinss]

It should be present, it's missing because there is no <dfn> markup for it in our specs so Shepherd can't find a link anchor, and Bikeshed doesn't see it. Needs a spec update for better markup.

css-values defines the <url> type, but apparently not the url() function.

[praveenpuglia]

So is there something I can do on my end and send PR somewhere to get this fixed?

[svgeesus]

Sure! Sending a PR that adds the correct markup to declare that function would be super helpful. The editors could also do it, but they are busy with a lot of other specs as well so a PR would get the change in faster.

[praveenpuglia]

So all we need is <dfn>url()</dfn> snippet like this for url()? If so, we might also need a paragraph of text which gives a brief intro to url() like it does for attr() or toggle(). Example -

The <dfn>toggle()</dfn> expression allows descendant elements
to cycle over a list of values instead of inheriting the same value.

[plinss]

Basically, yes, but the <dfn> also needs an id or to be inside something with an id (like a heading) so that it serves as an anchor for other specs to link to. For specs using bikeshed (css-values-3/4), the id will be automatically generated by bikeshed, however CSS2.2 uses a different pre-processor, I'm not sure if it adds ids to <dfn>s or not.

For completeness, both Bikeshed and Shepherd also need type information for the <dfn> e.g. <dfn data-dfn-type='function'> but both will use heuristics and should determine the type automatically based on the (). See the Bikeshed docs for more detail on that.

CSS2.2 should definitely get a <dfn>url()</dfn>, but as you say, might require prose changes to make sense in context. It's debatable whether a url function definition should be added to css-values or not, please consult the editors on that one, cc @tabatkins @fantasai