Re: [css-variables] Split declaring custom properties from using the values?

On 18/03/2014 08:41, Tab Atkins Jr. wrote:
> On Mon, Mar 17, 2014 at 5:31 PM, Alan Stearns <> wrote:
>> Hey all,
>> At the start of all the recent bikeshedding, Tab mentioned that one of the
>> primary use cases for custom properties is to do CSS polyfills. I’m very
>> much looking forward to that future day when there is enough custom
>> property support across browsers to do this.
>> I’m wondering whether that day might come faster if we separate declaring
>> custom properties (which is all a polyfill needs) from using the custom
>> property values in other declarations. It’s a smaller step for each
>> browser to take, and recent #webkit IRC chat makes me think that project
>> might be interested in this approach. Would Blink and/or IE be willing to
>> take this first step sooner than taking on all of the current level 1
>> draft?
>> I’m suggesting that we take section 3 of the current draft and move it to
>> level 2, if that gets us to better CSS polyfills faster. If this works, it
>> might even accelerate both steps - once declaring custom properties are in
>> place, adding code to use them becomes a smaller step, too.
> Given that Firefox is already about to ship with var(), I don't think
> it's a good idea to punt it to another level - we'd just pull it back
> in almost immediately.
> However, I *do* think it's worthwhile to emphasize more strongly that
> custom properties are just that - custom properties - and that using
> them as sources for variables is just one possible use, and to
> emphasize within Blink that we can just implement the "custom
> properties" part (as that's fairly easy), and then do the var() part
> later.

Agreed. It’s good to emphasize the separation, and it’s fine for a 
browser to only implement part of a spec, but I don’t think it’s worth 
punting to level 2 of the spec.

Simon Sapin

Received on Tuesday, 18 March 2014 01:43:42 UTC