Re: [xml-dev] The purpose of a namespace URI is ...

[David Carlisle <davidc@nag.co.uk>]

On 30/11/2012 16:40, Costello, Roger L. wrote:
> Hello David,
>
>> The local part in that case is not referring to markup or an XML
>> vocabulary at all, it is just the identifier of an error, the identifier
>> is almost never used in XML markup.
>
> So,
>
>      {http://www.w3.org/2005/xqt-errors} FOER0001
>      {http://www.w3.org/2005/xqt-errors} FOER0002
>      {http://www.w3.org/2005/xqt-errors} FOER0003
>      ...
>
> is not an XML vocabulary but,
>
>      {http://www.bookstore.org}BookStore
>      {http://www.bookstore.org}Book
>      {http://www.bookstore.org}Author
>      ...
>
> is an XML vocabulary?
>
> Why?
>
> What distinguishes them that allows me to know this?

Nothing. Both are just a list of names. If you happen to know from some 
information that someone has defined an XML vocabulary using the second 
list as element names, that is additional information that you have (but 
I didn;t have until you just told me)

>
> So the first set of xs:QNames is not an XML vocabulary but the second set of xs:QNames is an XML vocabulary?
>
> Why?
>
> I thought that -- by definition -- an XML vocabulary is a set of xs:QNames, where each local part has the same namespace URI part.
>

Well if you introduce the term you get to define it how you like. I 
don't think there is a standard definition of "XML vocabulary" but I 
would have expected it to describe a set of XML documents.

(For natural language  "vocabulary" might arguably be a list of names 
separate from grammar but that isn't how it is normally used for xml I 
think)


So some XML documents are in the docbook XML vocabulary, some are XHTML, 
some are MathML. However the term is applied to natural languages where 
sometimes it means a word list as opposed to grammar in the case of XML 
I think most definitions of "vocabulary" do involve a
grammar component. (Although that component is never identified by a 
namespace which is why different versions of xhtml or xslt can share 
namespace.
> No?
>
> /Roger
>
David



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