XML processor profiles: An introduction

1. Background

Any W3C spec. that defines an XML language or processes XML

• XML Schema
• XPath
• SVG
• ...

Defines or relies on a data model

• XPath 1.0 DM
• XDM
• (Infoset)

And often has language which constrains in some way the construction of instances of that data model

This specification requires as a precondition for ·assessment· an information set as defined in [XML-Infoset] which supports at least the following information items and properties:

This specification conforms to the XML Information Set [Infoset]. The following information items must be exposed by the infoset producer to construct a data model unless they are explicitly identified as optional:

2. Flexibility wrt XML processing

The XML specification provides a number of alternative approaches to processing an XML document

• Validating or not
• If not validating, processing external subset or not

The XML specification is also . . .

shall we say 'uneven' in the detail with which it requires XML processors to pass information about the document being processed to "the application".

So attributes are required to be reported

And element text content

• But not elements as such

Finally there are a number of 'low-level' XML processing operations which are not part of the XML specification itself:

• Implementing xml:base
• Implementing xml:id
• Implementing XInclude

3. The XML Processing Model WG Charter

The XProc WG's charter actually specified two deliverables

1. A default XML Processing Model [bows to Murray Maloney]
2. A scripting language for XML pipelines [bows to Norm Walsh]

We were unwilling (or perhaps just unable) to deliver on (1) as its authors perhaps intended

• But we have made the traditional up-level response
• That is, attempted to provide a vocabulary with which other specs can succinctly mandate a particular set of processing requirements

We have called the items in that vocabulary XML processor profiles

4. XML processor profiles

An XML processor profile specifies two kinds of things:

• What kind of processing is required
• What information must be reported

5. The XML processor profiles spec

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XML processor profiles

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