Re: What would count as an unbiased survey?

On May 29, 2009, at 14:41 , Henry S. Thompson wrote:
> All of which raises the question: What _would_ constitute reliable
> evidence of frequency of usage of the four major schema languages
> (DTD, XSD, Relax NG, Schematron)?
> Note once again in closing that this is _not_ a "my language is better
> than your language because more people are using it" discussion, but
> rather an attempt to support the proposition that maintaining and
> improving W3C XML Schema is important for W3C because it has a
> substantial user community on (and off) the Web.

If a survey is made, a good model could perhaps be the State of the  
Web 2008 survey:

That being said, sorry if I'm a little thick but I decreasingly  
understand what we would be trying to achieve with such a survey? As  
passionately as I may dislike XML Schema, there is little doubt that  
it is used a lot out there. Or more precisely, that a lot of languages  
are defined using XML Schema  the distinction being that in a fair  
number of cases that I've seen the schema may be in the specification  
but then no one ever uses it as part of the production chain.

Which brings me to my primary point: more than reflecting on what  
schema language should get what resources in times of constraint,  
shouldn't we take a step back, look at how XML is used today, and  
figure out how we would like to help and shape it over the next  
decade? I'm willing to bet that any serious take on this will shake  
out precisely what needs be done around the schema issue  and will be  
more generally useful.

In my experience, an awful lot of users out there pick XML Schema  
either because they don't know about the alternatives, or because  
"it's the W3C thing". Since as often as not they don't actually put  
the schema to use  in fact it's not rare that their schemata would be  
seriously broken, even though betters tools are reducing that issue   
they don't really have an opinion on whether XML Schema or anything  
else is what they need. It's just there.

This is strongly tied to the misperception that when defining a  
language one absolutely needs to have a schema, and the joint  
misperception that having defined a schema, processing rules for user- 
agent and versioning strategies are naturally solved issues.

What I'm getting at here is that I believe that what we most need is  
some form of guidance  possibly in the form of best practices  for  
the usage of XML in various situations. Whether W3C is the best place  
to define these (given that they wouldn't produce a standard) is an  
exercise I'm happy to leave to another day  though an IG could  
perhaps work.

There's a lot of experience in defining XML languages from various  
groups, notably inside W3C. It would be great at the very least to  
document that. It seems to me that whenever I stumble into a new  
standardisation effort both inside W3C and outside (e.g. OMTP, OMA,  
3GPP, TV Anytime, MPEG...) I have to restate the very same things  
about picking the schema language that best fits based on genuine use  
cases and requirements rather than "just because", on the fact that a  
schema is rarely enough for validation, on versioning strategies, on  
user-agent error-handling, on processing models... and my throat feels  
rather raw from all that typing, especially since it usually takes a  
few rounds of discussion before people start to understand the  
problem. I'd love to have something to point at instead.

I took a first semi-serious stab at it for the latest XML Prague (PDF: 
  , slides + video: 
  and it was well received  in fact I'm still getting questions about  
it even from people who weren't there. I have neither the time, the  
resources, nor the experience to elaborate on that in a solid, serious  
manner that will cover enough of the XML-using community  but I think  
that identifying problematic usage patterns will get us closer to  
something widely useful than figuring out which schema language is  
used most. The broader view on XML usage ought to shake out what  
really needs resources.

Robin Berjon -
     Feel like hiring me? Go to

Received on Friday, 29 May 2009 13:47:15 UTC