Re: Namespace: what's the correct usage?

[Kohsuke KAWAGUCHI <kohsukekawaguchi@yahoo.com>]

I'm glad to know that we are not the only ones who have opinions about
this.


> Bottom line. Why should everyone have to use namespaces in a particular way?
> I just don't get it...

I'm just trying to say that everyone should avoid using unqualified
local elements. It doesn't mean we have to use it in only one way.



> Actually, I provided that example because I thought you may be happier with
> it. In reality I use the class name for the top-level element. Why? Because
> typically I'm serializing an instance of a class and I probably don't know

OK, then take a look at another example of yours. I think you agree to
unqualify title, genre, and familyName.

<p:book xmlns:p='urn:x1'>
  <title>The Hobbit</title>
  <genre>Fantasy</genre>
  <p:author>
    <title>Dr</title>
    <familyName>Tolkien</familyName>
  </p:author>
</p:book>

But I guess you would object to unqualify <author> element. But why?
"author" is a field of an instance of the book type, just like title and
genre do.


If you don't object to unqualify <author> element. Then the root element
is the only element in your instance that is qualified. Then what is
the reason to qualify <book>? Why not unqualify all?

Technically, your statement that the "unqualified-local" doctrine is
suitable for "data serialized as XML" is wrong.



> No, this was not invented by XML Schema, unqualified elements are allowed by
> the namespaces rec just as unqualified attributes are allowed by the
> namespaces rec.

Of course it is "allowed".  But it's just that nobody imagined that such
an interpretation is possible.


> Again, I reiterate, it's not that the qualify-all approach is wrong, it's
> that I don't see it as the only approach.

I know. I can't state without some hesitation that it is THE only one
approach. But I believe the unqualified-local doctrine is wrong.


> And it's used by SOAP which is a fairly popular technology, in fact I'd say

That's why I really want to know if there is any other spec that uses
the same doctrine.  So far, nothing is mentioned by anyone.

I checked XML-RPC but it doesn't use XML namespaces at all.


> > If so, the innocent authors should be warned not to be trapped to such a
> > small dialect just because he/she wants to use XML Schema. And in fact
> > there are many practical reasons (vulnerability to the change of the
> > schema structure, more typing, etc.) that he/she should avoid it.
> 
> [MJG]
> What authors? There are no (few?) authors for SOAP messages, unless you

I meant "the innocent schema authors" who are just beginning to learn
XML Schema.


> And why is this a 'small dialect'?

Because virtually every known schema (except SOAP) uses the "qualify-all"
doctrine.


> Why does using unqualified local elements lead to 'vulnerability to the
> change in schema structure' and 'more typing'?

"It is vulnerable to the change in a schema file" because instance
documents have to be changed if you change one of your local declaration
to a global one so that it can be shared.

"It needs more typing" because you can't use the default namespace
declaration.

I think these are objective facts.


> > An explanation along with this line may be more adequate.
> Err, I didn't understand this last sentence?

Sorry. I meant that an explanation along with this line is probably more
adequate for my "XML Schema: DOs and DON'Ts", as the reason of why one
should avoid unqualified local elements.


regards,
----------------------
K.Kawaguchi
E-Mail: kohsukekawaguchi@yahoo.com