XML processor profiles

1 Background

The XML specification [Extensible Markup Language (XML) 1.0 (Fifth Edition)] defines an XML processor as "a software module. . .used to read XML documents and provide access to their content and structure. . .on behalf of another module, called the application." XML applications are often defined by building on top of the [XML Information Set (Second Edition)] or other similar XML data models such as [XML Path Language (XPath) Version 1.0] or [XQuery 1.0 and XPath 2.0 Data Model (XDM)], understood as the output of an XML processor. Such definitions have suffered to some extent from an uncertainty inherent in using that kind of foundation, in that the mappingXML processors perform from XML documents to data model is not rigid. Some of this stems from the XML specification itself, which leaves open the possiblity of reading and interpreting external entities, or not. Some stems from the growth of the XML family of specifications: if the input document includes uses of XInclude, for instance.

This specification addresses this issue by defining several XML processor profiles, each of which fully determines a data model for any given XML document. It is intended as a resource for other specifications, which can by a single normative reference establish precisely what input processing they require.

The profiles defined here are appropriate for processing both XML 1.0 [Extensible Markup Language (XML) 1.0 (Fifth Edition)] and XML 1.1 [Extensible Markup Language (XML) 1.1 (Second Edition)] documents. References to XML or XML Namespaces below should be understood as references to 1.0 or 1.1 as required by the relevant document or application.

2 The minimum XML processor profile

The minimum approach to the construction of a data model from a well-formed and namespace well-formed XML document requires the following:

1. Processing of the document as required of conformant non-validating XML processors while reading all external markup declarations;

2. Maintenance of the base URI property of each element in conformance with [XML Base];

3 The basic XML processor profile

The basic recommended approach to the construction of a data model from a well-formed and namespace well-formed XML document requires the following:

1. Processing of the document as required of conformant non-validating XML processors while reading all external markup declarations;

2. Maintenance of the base URI property of each element in conformance with [XML Base];

3. Identification of all xml:id attributes as IDs as required by [xml:id Version 1.0]

4. Replacement of all include elements in the XInclude namespace, and namespace, xml:base and xml:lang fixup of the result, as required for conformance to [XML Inclusions (XInclude) Version 1.0 (Second Edition)].

The following [XProc: An XML Pipeline Language] pipeline, when implemented by a conformant processor which processes its input as required by point (1) above, implements the default process:

<p:pipeline xmlns:p="http://www.w3.org/ns/xproc">

  <p:xinclude fixup-xml-base="true" fixup-xml-lang="true"/>

</p:pipeline>

4 Other profiles (non-normative)

The profiles defined here, particularly the 3 The basic XML processor profile, can be used as a starting point for the definition of further profiles. For example, the media type registrations for stylesheet languages applicable to XML such as text/xsl or text/css might define a profile specifying appropriate <?xml-stylesheet type="[their media type]" . . .?> processing in addition to the processing required by 3 The basic XML processor profile.

5 Conformance

Conformance is a matter for any specification which references this one to mandate, expressed in terms such as "Conforming implementations must construct input data models from XML documents as required by the basic XML processor profile."