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RE: Motivations for namespaces (sorry)

• To: "Chiusano Joseph" <chiusano_joseph@b...>,"Eric van der Vlist" <vdv@d...>
• Subject: RE: Motivations for namespaces (sorry)
• From: "Dare Obasanjo" <dareo@m...>
• Date: Thu, 10 Jul 2003 10:50:21 -0700
• Cc: <xml-dev@l...>
• Thread-index: AcNHCY2Ab/e1uCWVT2GpeKquF/6ylAAAi3ta
• Thread-topic: Motivations for namespaces (sorry)

This is a hack. A hack I wouldn't suggest people use in practice unless they have control over the XML that is being processed or can guarantee what prefix<->namespace binding will exist in the document. 

________________________________

From: Chiusano Joseph [mailto:chiusano_joseph@b...]
Sent: Thu 7/10/2003 10:33 AM
To: Eric van der Vlist
Cc: xml-dev@l...
Subject: Re:  Motivations for namespaces (sorry)



<Quote>
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?
</Quote>

+1 - Additionally, how can one guarantee a uniform usage of namespace
prefixes?

Kind Regards,
Joe Chiusano
Booz | Allen | Hamilton

Eric van der Vlist wrote:
>
> 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@o...)</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
> ------------------------------------------------------------------------
>
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