RE: Namespaces, schemas, Simon's filters.

[Tim Bray <tbray@textuality.com>]

It's difficult for Matt Fuchs and I to have a straightforward 
discussion because there's some terminology getting in the 
way: Matt calls elements which are in a namespace "global" and 
those which aren't "local".  I suspect that he associates some 
[schema-related?] semantics with the terms "local" and 
"global".

It kind of puzzles me, because as we saw here recently, a schema 
can specify many different validation policies for elements of type 
<myNS:x> depending on their context, just as any other software is 
free to take the context into account in applying semantics to 
markup.  So I can't see any sense in which the term "global" is 
helpful.

Put another way: whether or not an element is in a namespace is 
orthogonal to whether its semantics are context-sensitive.  Given 
this, why would one ever not use namespaces?

To conclude: I still claim that when you're inventing a markup 
vocabulary, interoperability, robustness, and flexibility are 
improved by placing all your elements in your namespace.  In 
addition to the problems I pointed out before, Matt highlighted 
another: if you qualify all your own elements, you can't get screwed
up by other people's default-namespace declarations; elements that 
are "local" in Matt's sense of the word obviously can be. -Tim