Re: [css3-conditional] Resolving issues

Le 26/09/2012 19:33, Tab Atkins Jr. a écrit :
> I agree that it's strange, but you simply*don't know*  whether it
> should be true or not.  My suggested solution is kinda similar to
> NaN-poisoning, where once a NaN is introduced, it remains NaN until
> you do something special with it.  This just wipes out the entire
> unknown clause.

I see the comparison, but I still believe we should not do this. For 
example:

@supports foo(bar) { /* The new-and-shiny thing */ }
@supports not foo(bar) { /* The almost-as-good CSS 2.1 fallback */ }

The expectation here is that one of the two at-rules will apply. With 
your suggestion none of them apply, and we get unstyled content. Are 
there more complex cases where the author would actually want a 
"NaN-like" value for unknown functions in @supports?

-- 
Simon Sapin