Re: should CSS, HTML, etc. documents bear version information? (XMLVersioning-41?)

On 4/1/07, Dave Pawson <dave.pawson@gmail.com> wrote:
> Downstream processing of xml content requires validation and hence
> versioning to assure the processor that the content being worked
> is as expected.

Processing content requires only that the recipient be able to
understand it.  Validation plays no role in that.  At best it's just
one way that a document recipient can identify content that might not
be understood.  But even without validation the content would
certainly be found to be "invalid" eventually, as processing is
attempted.

IME, if you define a decent extensibility model such that future
documents can be processed by old software, not only do you not need
validation, but it actually gets in the way of building evolvable
systems.  I've written about this recently;

http://www.coactus.com/blog/2006/12/validation-considered-harmful/

I agree completely with Lachlan's comments.

Mark.