W3C home > Mailing lists > Public > www-style@w3.org > October 2012

Re: [css-variables] Which value is substituted?

From: Tom Potts <karaken12@gmail.com>
Date: Fri, 5 Oct 2012 07:36:42 +0100
Message-ID: <CAF2aeH0CT4ykhWLxs7vzph=2u0gKuWkHwd_bTYX_bx6pOuAYfA@mail.gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>, François REMY <fremycompany_pub@yahoo.fr>
Cc: www-style@w3.org
Thanks, Tab, François, I think those answers comprehensively answer my
question. :o)

If I can hijack the thread a little: François, why did you pick the
specified value for 'use()'? The reason I started thinking about this was
the kinds of non-obvious circular references Tab mentioned in an older
thread.  For example
    line-height: 2em;
    font-size: use(line-height);
is a circular reference if 'use' produces the computed value; if it's
reversed, as in
    font-size: 2em;
    line-height: use(font-size);
then neither version is a circular reference, but using the specified value
produces lines twice as high as using the computed value.

So I'm not sure which is "correct" (if either) for 'use'; I'd be interested
to hear why you've gone in the direction you have.

Thanks,
Tom

On 4 October 2012 17:38, Tab Atkins Jr. <jackalmage@gmail.com> wrote:

> On Wed, Oct 3, 2012 at 11:48 PM, Tom Potts <karaken12@gmail.com> wrote:
> > Hi, all.  Sorry if this has already been answered, but it wasn't clear
> to me
> > from reading the spec.  When using a custom property reference (i.e.
> > "var(foo)"), the spec says to substitute the "value" of the associated
> > variable (relevant quotes are "... the variable's value is substituted as
> > normal" and "A variable is substituted for its value in the property
> value
> > at computed-value time.").  What's not clear to me here is what "value"
> > actually means in this context.  The only reasonable candidates I can
> think
> > of are the specified value and the computed value, but I think it's
> > important which one of these is meant, and I don't think it's clear in
> the
> > spec as written.
>
> Oh, good catch!  I don't actually define that.  I'll fix.
>
> It's the computed value (after resolving any var() references in the
> corresponding var-* property, so that you're left with a var()-less
> value).
>
> ~TJ
>
Received on Friday, 5 October 2012 06:37:10 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 17:21:01 GMT