Re: [xml-dev] Motivations for namespaces (sorry)

["Eric van der Vlist" <vdv@dyomedea.com>]

Thomas B. Passin said:
> [Eric van der Vlist]
>>
>> Chiusano Joseph said:
>> > Eric,
>> >
>
>> I would argue that in this case, what's identifying your "document
>> type" is the xsi:schemaLocation more than the namespaces!
>> My point was rather that namespaces alone are not enough to guess
>> what's the document as a whole is about.
>
> In the task I described a post ago, it is exactly the namespace URI -
> OK, in practice it really is the prefix,  so there! - that is so
> helpful.
.../...
> That's important.  That's why virtually all xslt stylesheets use xsl:.
> That's why virtually all XML Schemas use xs: or xsd:.  That's why xhtml
> documents almost always use html: or xhtml:.  It is why we name
> variables with mnemonic names rather that "dhf340cksdfnmg".  It is
> mostly why we use readable URLs instead of GUIDs.

Thomas,

This sounds like a really innovative use of namespace prefixes! What about
languages such as Schematron and Relax NG (not to mention Examplotron
which is worse) which use to use a default namespace?
Also, let's take a RSS 1.0 document:

<?xml version="1.0" encoding="utf-8"?>
 <rdf:RDF
  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dc="http://purl.org/dc/elements/1.1/";
  xmlns:sy="http://purl.org/rss/1.0/modules/syndication/";
  xmlns:co="http://purl.org/rss/1.0/modules/company/";
  xmlns:ti="http://purl.org/rss/1.0/modules/textinput/";
  xmlns="http://purl.org/rss/1.0/";
>
   <channel rdf:about="http://meerkat.oreillynet.com/?_fl=rss1.0";>
    <title>Meerkat</title>
    <link>http://meerkat.oreillynet.com</link>
    <description>Meerkat: An Open Wire Service</description>
    <dc:publisher>The O'Reilly Network</dc:publisher>
    <dc:creator>Rael Dornfest (mailto:rael@oreilly.com)</dc:creator>
    <dc:rights>Copyright &#169; 2000 O'Reilly &amp; Associates,
    Inc.</dc:rights>    <dc:date>2000-01-01T12:00+00:00</dc:date>
    <sy:updatePeriod>hourly</sy:updatePeriod>
    <sy:updateFrequency>2</sy:updateFrequency>
    <sy:updateBase>2000-01-01T12:00+00:00</sy:updateBase>
    ...

How do you say that's its a RSS document? If we had to use a "rss" prefix
for the document element, that would give:
<?xml version="1.0" encoding="utf-8"?>
 <rss:RDF
  xmlns:rss="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
  xmlns:dc="http://purl.org/dc/elements/1.1/";
  xmlns:sy="http://purl.org/rss/1.0/modules/syndication/";
  xmlns:co="http://purl.org/rss/1.0/modules/company/";
  xmlns:ti="http://purl.org/rss/1.0/modules/textinput/";
  xmlns="http://purl.org/rss/1.0/";
>

That's technically valid, but isn't it most confusing?

Eric
-- 
Freelance consulting and training.
                                            http://dyomedea.com/english/
------------------------------------------------------------------------
Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
------------------------------------------------------------------------