Experimental and non-experimental implementations in Snapshot-2010

Here is a re-write of sections 3.3 and 3.4 along the lines that I understood Sylvain to be suggesting and also attempting to incorporate the suggestions that were made during the discussion this morning. To the extent possible, I tried to use the text that was already present and to, mostly, re-order the description to emphasize that there were two kinds of implementations and to be clear when each type of implementation could occur. I recognize that the English probably needs some clean-up to improve the readability, but I wanted to get the idea on the floor for comment. The original text is at:
  http://dev.w3.org/csswg/css-2010/#experimental
3.3. Implementations

A key goal of CSS is to establish and maintain the interoperability of CSS across implementations. To achieve this goal there are two levels of implementation: experimental and non-experimental. Prior to a specification reaching the Candidate Recommendation stage, all implementations are experimental. To avoid clashes with future CSS features, the CSS2.1 specification reserves a prefixed syntax<http://www.w3.org/TR/CSS21/syndata.html#vendor-keywords> for proprietary property and value extensions to CSS. The CSS Working Group recommends that experimental implementations of features in CSS Working Drafts also use vendor-prefixed property or value names. This avoids any incompatibilities with future changes in the draft.

Once a specification reaches the Candidate Recommendation stage, non-experimental implementations are possible. The CSS Working Group requests that non-experimental CSS renderers submit an implementation report demonstrating compliance to the W3C test suite(s) for the implemented features before releasing an unprefixed implementation of any CSS features. Implementors should implement the non-prefixed syntax for any feature they demonstrate to be correctly implemented according to spec. Having a W3C test suite for a feature requires collecting test cases for that feature; implementers of the feature are encouraged to submit the test cases that they use for the feature. The W3C CSS Working Group is the sole judge of the correctness of such test cases. Further information on submitting testcases and implementation reports can be found from on the CSS Working Group's website at http://www.w3.org/Style/CSS/Test/.

CSS2.1 implementations are encouraged, but not required, to submit such a report.




Steve Zilles