See below.

On 11/8/10 10:27 AM, Costello, Roger L. wrote:

QUESTIONS:

1. Are all XML processors namespace-aware? That is, do all XML processors understand the colon in a name as a delimiter between a namespace prefix and a local name?

By definition, no. In practice, I hope so.

2. Are there XML processors that are namespace-unaware? That is, are there XML processors that treat colons as just another character?

Maybe, but you shouldn't use them.

3. Is namespace checking (checking that each prefix is bound to a namespace) a separate activity from XML checking? Is there such a thing as a namespace processor? If so, are XML instance documents first checked by an XML processor and then by a namespace processor:

XML instance document -->  XML processor -->  namespace processor

No, namespaces were retroactively grafted into the XML 1.0 foundation. They're not properly layered (as perhaps they should have been).

4. When we talk about an "XML processor" do we really mean XML processor + namespace processor"?

In practice, yes.

5. Consider the task of checking that "ex:" is bound to a namespace. Is that an XML processor task? Or, is that a task for a higher-level application; e.g., a namespace processor?

Yes, it's the namespace-aware processor's task. Not a higher-level concern.

6. If the ex in<ex:Comment>  is not bound to a namespace, is that really an XML well-formedness error?

Not technically. But you might say it's not "namespace-well-formed". And, actually, I just checked and there's a reason I used that phrase: http://www.w3.org/TR/xml-names/#dt-nwf

Evan