RE: infinite depth to namespaces

[Tim Bray <tbray@textuality.com>]

At 02:29 PM 30/08/01 -0700, Michael Brennan wrote:
>The problem is, if we yield to these notions, XML does not have a very
>bright future. The consensus that some are trying to achieve on the matter
>of what is the correct practice for the one information set all schemas
>should present to all applications is simply not achievable. 

Don't sweat it.  The only normative definition of XML is syntactical.  
The only normative definition of namespaces is syntactical.  These
definitions are implemented by tons of interoperable software.  The 
Infoset, simply because it has come after XSLT and XPath and DOM
and SAX chronologically, is an afterthought.  The PSVI is an 
elaboration of that afterthought.  Working programmers are generating 
XML with various flavors of print() statement and reading it through a 
variety of interfaces (including Notepad :)) and not apparently having 
too much difficulty.

XSDL and its competitors are an unqualifiedly good thing.  They
provide immensely better expressive hooks for the language designer
and for the authoring program that wishes to support a human in 
direct creation of XML content.  The data typing system will have
lots of supporting libraries which will facilitate all sorts of
interchange tasks.  So let's not diss the contribution of the schema 
folks.

The overwhelming majority of real XML deployments at this time do
not do runtime DTD validation, and it's hard to believe that 
they'll do runtime schema validation.  In very many cases the
knowledge that is encoded declaratively in schemas ends up being 
re-encoded procedurally in compiled code, along with all sorts of 
other business-logic sanity checks (e.g., is this a real employee 
ID number?).  I do think however that there will be lots of callouts 
to libraries built around the XSDL data types, for doing validation 
and conversion at run-time.  

Matt Fuchs et al are throwing around interesting experimental
ideas about getting a cleaner mapping between names and definitions,
which is a complex and non-obvious problem, and more power to
them.  But I don't think that all the PSVI theorists in the world,
laid end-to-end, are any threat to the everyday working usefulness
of XML. -Tim