block-based parsing?

Hi,

I know there has been some recent discussions on how and why CSS should
have a versioning system [1], and I also understand that the CSS Working
Group isn't keen into using versioning.

While I mostly agree with the commenters about the usefulness of having
versioning in the CSS style sheets, I'm wondering whether the group has
considered an alternative solution (detailed below), which would not
solve all the issues raised by the lack of versioning, but would at
least help authors writing CSS across levels.

Most of CSS techniques today deal with how using the various bugs in CSS
parsers to get such or such a rule applied. I was wondering whether the
idea behind that could actually be incorporated into the spec with an
at-rule parsing command, à la @mustUnderstand.

Namely, such a rule would require a parser to skip the entire block
contained into the @mustUnderstand scope if there is at least one rule
it can't parse or containing a property it doesn't know.

This would make it much easier to create style sheets that incorporate
properties or syntax elements defined in later versions of CSS. It
wouldn't solve all the problems, but would certainly help in many cases.

Comments?

Dom

1. http://lists.w3.org/Archives/Public/www-style/2005Aug/0252.html
and http://lists.w3.org/Archives/Public/www-style/2005Aug/0246.html for
instance
-- 
Dominique Hazaël-Massieux - http://www.w3.org/People/Dom/
W3C/ERCIM
mailto:dom@w3.org