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

First of all, I agree with pretty much everything that Henry has written 
in his note.  One refinement I would suggest:

Henry Thompson writes:

> What's important here is that consumers' wishes are paramount, but it
> _is_ none-the-less possible for producers to state their wishes as
> well.

I don't think it's in all cases expressing a wish.  Even in the typical 
case where the consumer has to make the ultimate decision on how to 
process information, how much validation to do, against what rules, etc. 
it can be very useful to allow the producer to indicate what rules he or 
she used in creating the content.  For me, that's the fundamental reason 
for allowing language or specification identifiers.  Sometimes it's worth 
the trouble, sometimes it's more confusing than helpful.

Also:  I think it's important to realize that having a single version 
identifier is in tension with allowing distributed extensibility.  As long 
as you have a language that's evolved reasonably centrally, it's tractable 
for those involved to coordinate labeling of version information.  When 
you have compound languages that allow piece parts to be invented by more 
or less anyone, then you may have HTML version x, with div #1 embedding an 
SVG version #2, or even in the worst case div#3 being a wrapper for some 
content originally authored by someone else in SVG version #1.  It may 
even be that someone has just added a few local attributes to an otherwise 
standard HTML page.  In such cases, trying to label a document with a 
single language version is at best a compromise, and at worst 
inappropriate.

--------------------------------------
Noah Mendelsohn 
IBM Corporation
One Rogers Street
Cambridge, MA 02142
1-617-693-4036
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Received on Tuesday, 3 April 2007 15:20:09 UTC