Re: [css-variables] ...let's change the syntax

On Sat, Mar 29, 2014 at 3:31 AM, Jonathan Kingston
<> wrote:
> Hi All and Tab Atkins jr,
> After careful review of the following message, I think I get the motivation
> for this change a lot more than changing the syntax for variables.
> Would it be worth instead of dropping the "--" prefix when in "var()" scope
> dropping the use of "var()" when and where the parser could cope?

Note - we don't drop the -- prefix when putting a custom property name
in var().  Your examples below acknowledge this, so you may already be

> So for example, the following would be an issue
>   height: --profile-image-heightpx;
> So var would be used:
>   height: var(--profile-image-height)px;
> However this would be fine:
>   color: --profile-heading-color;
> This would give a similar feel to variable interpolation in many other
> languages and template engines - it may also break the boundaries more of
> users thinking it's main use is for variables.

Unfortunately, this isn't great.  There are already a few places in
CSS that accept <custom-ident> values, which technically allow
precisely this syntax, and so there would be ambiguity.

We could potentially disallow <custom-ident> from having a -- prefix,
so there was no ambiguity, but then we're splitting syntax hairs,
which tends to be very confusing for authors.  (Having to remember
that X values uses the Y grammar, but not quite, because it excludes Z
and W, is very difficult for people in practice, though it always
sounds like it should be easy.)

There's also the fact that a plain ident doesn't "jump out" very much,
at least not as much as a function like var().  This is one of the
benefits of var() - it's *immediately obvious* when you're using a
variable, which is perceived as a benefit.

Finally, even if we allowed this, we'd still need to *also* allow
var(), so that you could do things like fallbacks.  Having two
syntaxes for doing the same thing is another thing that leads to
confusion for authors, and we try to avoid it when we can unless
there's a really good benefit.


Received on Saturday, 29 March 2014 22:53:13 UTC