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CSS Variables published as First Public Working Draft!

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Tue, 10 Apr 2012 10:21:22 -0700
Message-ID: <CAAWBYDDnKZcvFn-4t+BjfVmzvj4dRpNzrcCb5tGf0+mC7K7bqQ@mail.gmail.com>
To: www-style list <www-style@w3.org>
[Resent for great justice, this time with a link to the spec.]

I'm happy to announce that CSS Variables has just been published as a
First Public Working Draft!

http://www.w3.org/TR/css-variables/

Large documents or applications (and even small ones) can contain
quite a bit of CSS. Many of the values in the CSS file will be
duplicate data; for example, a site may establish a color scheme and
reuse three or four colors throughout the site. Altering this data can
be difficult and error-prone, since it's scattered throughout the CSS
file (and possibly across multiple files), and may not be amenable to
Find-and-Replace.

This module introduces a family of custom user-defined properties
known collectively as variable properties, which allow an author to
assign arbitrary values to a property with an author-chosen name, and
then use those values in other properties elsewhere in the document.
This makes it easier to read large files, as seemingly-arbitrary
values now have informative names, and makes editting such files much
easier and less error-prone, as one only has to change the value once,
at the variable definition site, and the change will propagate to all
uses of that variable automatically.

Variables have many more uses beyond helping maintenance.  One example
is theming - a generic stylesheet can be created that uses variables
for important colors, backgrounds, etc., with the expectation that it
will be paired with a site-specific stylesheet that gives all the
variables definitions.

Many existing variables systems provided inspiration for this module,
including SASS <http://sass-lang.com/> and a previous spec defining
pure CSS Variables written by Dave Hyatt and Daniel Glazman
<http://disruptive-innovations.com/zoo/cssvariables/>.  The approach
this spec eventually settled on - defining variables through CSS
properties rather than at-rules - offers a strict superset of the
functionality of those inspirational specs, and provides several
additional benefits.

This spec is in its infancy, and implementation has only just begun.
Feedback on the features and syntax is very welcome.  We are
attempting to keep this first iteration of the spec as simple as
possible, as even this basic functionality is much more complex than
it might appear, and so will likely defer feature requests until Level
2, but keep them coming anyway so we know what to work on next!

~TJ
Received on Tuesday, 10 April 2012 17:22:15 GMT

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