OASIS Mailing List ArchivesView the OASIS mailing list archive below
or browse/search using MarkMail.


Help: OASIS Mailing Lists Help | MarkMail Help



   re: RDF considered optional

[ Lists Home | Date Index | Thread Index ]
  • From: David Megginson <david@megginson.com>
  • To: "'XML-DEV'" <xml-dev@ic.ac.uk>
  • Date: Wed, 17 Mar 1999 17:57:19 -0500 (EST)

Jeffrey E. Sussna writes:

 > The RDF syntax spec states that "The RDF element is optional if the
 > content can be known to be RDF from the application context."
 > Can anyone clarify exactly what is meant by "application context"? 

That means that if you know in advance what you're reading, you don't
need to have an rdf:RDF element.  For example, if I define an
RDF-based format for exchanging Flight-Simulator scenery information
(FSML), and I never intend to embed this in a web page, etc., I can
just use something like this:

  <?xml version="1.0"?>

  <!-- Yes, Virginia, this is RDF-conformant! -->

  <fsml:Building xmlns:fsml="http://flightsim.com/ns/fsml#">
   <fsml:name>Lennox Generating Station</fsml:name>

What's really entertaining is that I can do this, and be
RDF-conformant, without even declaring the RDF namespace.

The most recent version of SiRPAC that I saw still chokes on this
example, but I consider that a bug in SiRPAC (or at least, a
deliberate implementation choice).

For the curious, here's the basic serialisation syntax for the same

  <?xml version="1.0"?>

  <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"

   <rdf:type resource="http://flightsim.com/ns/fsml#Building"/>
   <fsml:name>Lennox Generating Station</fsml:name>


Actually, this is *not* exactly identical because the RDF spec has a
bizarre requirement that when you use rdf:Description explicitly the
processor has to build about a zillion extra tuples for reification
purposes, whether you want them or not.  Go figure.

All the best,


David Megginson                 david@megginson.com

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@ic.ac.uk
Archived as: http://www.lists.ic.ac.uk/hypermail/xml-dev/ and on CD-ROM/ISBN 981-02-3594-1
To (un)subscribe, mailto:majordomo@ic.ac.uk the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo@ic.ac.uk the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa@ic.ac.uk)


News | XML in Industry | Calendar | XML Registry
Marketplace | Resources | MyXML.org | Sponsors | Privacy Statement

Copyright 2001 XML.org. This site is hosted by OASIS