XML Information Set Requirements

W3C Note 18-February-1999

This version: http://www.w3.org/TR/1999/NOTE-xml-infoset-req-19990218.html
Latest version: http://www.w3.org/TR/NOTE-xml-infoset-req.html
Editors: David Megginson()

Copyright  ©  1999 W3C (MIT, INRIA, Keio), All Rights Reserved. W3C liability, trademark, document use and software licensing rules apply.

Status of this document

This is a W3C Note produced as a deliverable of the XML Information Set WG according to its charter and the current XML Activity process. A list of current W3C working drafts and notes can be found at http://www.w3.org/TR.

This document is a work in progress representing the current consensus of the W3C XML Information Set Working Group. This version of the XML Information Set Requirements document has been approved by the XML Information Set working group and the XML Plenary to be posted for review by W3C members and other interested parties. Publication as a Note does not imply endorsement by the W3C membership. Comments should be sent to www-xml-infoset-comments@w3.org, which is an automatically and publicly archived email list.


This document lists the design principles and requirements for the XML Information Set, a meta-model for XML documents being developed by the World Wide Web Consortium's XML Information Set Working Group.

Table of Contents

1. Introduction
2. Design Principles
3. Requirements
4. References

1. Introduction

The W3C's XML 1.0 Recommendation [XML] describes the physical representation of XML documents. We expect, however, that XML-based standards will usually be defined at a higher, logical level: in other words, standards will tend to refer to abstract objects like element or data rather than to the physical sequences of characters that match the XML 1.0 Recommendation's syntactic productions.

The XML Information Set will describe these abstract XML objects and their properties. It will provide a common reference set that other specifications can use and extend to construct their underlying data models, and will help to ensure interoperability among the various XML-based specifications and among XML software tools in general.

The XML Information Set will be purely descriptive: it will identify a common set of abstract XML information without mandating a single type of processing behaviour or a specific API for XML-based software.

2. Design Principles

  1. The XML Information Set shall provide an abstract model for describing the logical structure of a well-formed XML 1.0 document (note that all valid XML 1.0 documents are also, by definition, well-formed).

  2. The XML Information Set shall be suitable for use as a common reference model for specifications (such as parsing APIs and query languages) and applications (such as editors and browsers) that deal with the structure of XML 1.0 documents.

  3. The normative portion of the XML Information Set specification shall be human-readable.

  4. The XML Information Set specification shall include a non-normative formal model that allows for machine testing and verification of the information set.

  5. The XML Information Set shall be designed to be interoperable with the W3C's DOM Level 1 Recommendation [DOM] and, as far as possible, with the XPointer Working Draft [XPointer], and with the XSL Working Draft [XSL].

  6. The working group shall consider the issue of document validation while designing the XML Information Set.

3. Requirements

  1. The model of the XML Information Set shall be derived from the XML 1.0 Recommendation [XML].

  2. The XML Information Set shall satisfy all of the information-reporting requirements of the W3C's XML 1.0 Recommendation [XML].

  3. The XML Information Set shall contain sufficient information for the creation of a well-formed XML document.

  4. The XML Information Set shall contain sufficient information to define equivalence for XML documents based on their logical structure.

4. References

W3C (World Wide Web Consortium). Document Object Model (DOM) Level 1 Specification Recommendation. Version 1.0. [Cambridge, MA]. http://www.w3.org/TR/REC-DOM-Level-1
W3C (World Wide Web Consortium). Extensible Markup Language (XML) Recommendation. Version 1.0. [Cambridge, MA]. http://www.w3.org/TR/REC-xml
W3C (World Wide Web Consortium). Extensible Stylesheet Language (XSL) Working Draft. Version 1.0. [Cambridge, MA]. http://www.w3.org/TR/WD-xsl
W3C (World Wide Web Consortium). XML Pointer Language (XPointer) Working Draft. [Cambridge, MA]. http://www.w3.org/TR/WD-xptr