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[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message] XSchema Spec - Namespaces (Section 3), Draft 3
 The latest version of the namespaces section follows. Because many more namespace issues are already addressed in section 2 of the spec, there is less to do here. The XSC:Namespace element has been retired. As always, a prettier HTML version of this will be posted shortly at http://purl.oclc.org/NET/xschema. Simon St.Laurent Dynamic HTML: A Primer / XML: A Primer / Cookies 3.0 XSchema and Namespaces XSchema uses namespaces for its own operations and also supports schemas that take advantage of namespace facilities. XSchema processors are responsible only for elements that use the XSchema namespace appropriate to the version of XSchema they are processing. Information in other namespaces may be used in the XSC:Doc and XSC:More elements and passed to other applications as the processor deems appropriate. Please note: the information in this section is based on the 2 August 1998 "Namespaces in XML" Working Draft and is will change to maintain conformance with that specification. 3.1 The XSchema Namespace XSchemas created using XSchema 1.0 have their namespace declaration built into the DTD as default xmlns and xmlns:XSC attributes of the XSchema element. Note that XSC:Doc and XSC:More must use the XSC: prefix because they declare other values for the default namespace name. Any XSchema element may use the XSC: prefix if desired, but it is not necessary. 3.2 Interaction with Other Namespaces XSchemas will often support document sets that have their own namespaces. To maintain interoperability with DTDs, XSchema provides mechanisms for declaring the namespace prefixes of elements declared by XSchemas. This allows documents and the XSchemas used to verify them to track the same namespace using different prefixes if necessary. XSchema-to-DTD converters should use the prefix attribute of an ElementDecl, AttGroup, or AttDef element to create DTD element and attribute declarations containing that prefix. DTD-to-XSchema converters should use the prefixes assigned in the DTD, and request further information about the 'real' namespace for the ns attribute. This may be accomplished by parsing a sample document instance, or by direct input from the person doing the conversion. The ns attribute is not required, but it does provide the XSchema with a level of understanding about namespaces that DTDs presently lack. If an XSchema contains the correct ns attributes, it is far better equipped to process documents that use namespaces without concern for the variability of prefixes. 3.3 Note Regarding Namespace Usage Namespaces are still in development at this time, and as such are subject to dramatic change. This specification was written making several assumptions, which may or may not prove to be true as the Namespaces draft evolves: 1. The only part of a namespace declaration that genuinely identifies the namespace is the ns production. The prefix only serves as a proxy for the full ns production. 2. The URLs in a namespace declaration will not need to be retrieved. The XSchema namespace declaration uses a PURL (permanent URL) provided by the OCLC. (For details on PURLs, visit http://purl.org.) PURLs use redirection to maintain a permanent address for sites that may change address. While XSchema specification information may be stored at the location to which the PURL server redirects visitors, XSchema applications should not rely on any of that information being there. Simon St.Laurent Dynamic HTML: A Primer / XML: A Primer / Cookies 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/ 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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