[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] RE: Another look at namespaces
At 08:30 AM 9/16/99 -0700, Andrew Layman wrote: >[Someone] wrote that, although a schema may be somehow associated with a >namespace, the "meaning" of markup will be determined in a number of ways >such as style sheets, or procedural code, or maybe the schema. I believe >this understates the importance of the schema. A schema makes a >contribution to the Infoset. It does this by providing default values and -- >under some recent proposals -- by indicating type information, which may be >considered also a form of default value. Elements defined by a schema, when >used in an instance document in a validating processor, will have these >default values available, and this fact is pertinent to the author of the >document. This means that an element is incompletely read if the schema for >it is not read. With all due respect to Andrew Layman, I find this to be a gross overvaluation of schemas, and a substantial contrast with both the XML 1.0 approach (which doesn't require validation) and with Tim Berners-Lee's comments, which included: >However, as we define languages for talking about languages >(XML and RDF schemas for example, even style sheets) >the document corresponding to the namespace URI becomes >the place where the namespace-author can put *definitive* >information about the intent of the namespace. This seems to leave the possibility _wide_ open that something other than a schema is lurking at the URI identified by the namespace. At the very least, there are multiple schema possibilities - XML and RDF, as noted above, and possibly even DTDs. Schema information should be an important _component_ of that information, certainly, but I see no reason why it should be the only, or indeed primary, component. For an example of a different possibility, you might explore my XPDL proposal at http://purl.oclc.org/NET/xpdl. Schema information, style information, and documentation are combined to provide a description of a document class. >For a namespace to be reliably useful, there must be a document >defining its contents and their meaning. A schema is, for many namespaces, >that document. An interesting opinion, to be sure, but not a claim made directly by the Namespaces in XML recommendation, and not necessarily a hard-and-fast rule. Simon St.Laurent XML: A Primer (2nd Ed - September) Building XML Applications Inside XML DTDs: Scientific and Technical Sharing Bandwidth / Cookies http://www.simonstl.com xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev@i... 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@i... the following message; (un)subscribe xml-dev To subscribe to the digests, mailto:majordomo@i... the following message; subscribe xml-dev-digest List coordinator, Henry Rzepa (mailto:rzepa@i...)
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