Re: [xml-dev] NVDL: A Disruptive Technology

[Jonathan Robie <jonathan.robie@redhat.com>]

Michael Kay wrote:
>> Those are two languages:  SQL and Java.  XML isn't a single language. 
>>     
>
> I don't see any difference. SQL, Java, and XML all provide syntax for
> describing user-defined data structures and constraints on the instances of
> those data structures.
>   

I agree.

But I'm not sure what the original comment was intended to convey. In 
what way is XML not a single language? There's essentially one markup 
language called XML. Is it not a single language because DTDs, W3C XML 
Schemas, and schemaless docs are all in widespread use, Relax-NG is 
popular with the cool crowd, and Those Who Know rely on Schematron?

You know, a bunch of people I know look at this fragmentation and 
conclude that it's best to do validation at the business level by 
writing code. Creating more schema languages doesn't convince them to 
rely more on schemas and less on code.

Jonathan