On Mon, Jun 16, 2008 at 11:20 AM, <> wrote:
Strictly conforming disallows the extensions. So
it does reduce the range of variability. But it doesn't eliminate
it. So I think there is a relationship there, but not one which in
itself guarantees interoperability.
The key thing with extensions is that if the spec allows for a feature then the output should be conformant (for that feature) rather than expressed as an extension, unless there is good reason to stray.
A simple, quantitative metric that could potentially be applied is the ratio of in-spec to out-of-spec content (where implementations are punished for [ab]using extensions), but then there are questions as to whether you cound #directives, #bytes, etc.
Sam
--
Sam Johnston
Australian Online Solutions
http://www.aos.net.au/
+61 2 8898 9090
