Extreme Markup Languages 2001: Proceedings

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Taxonomy of XML Schema Languages Using Formal Language Theory

Makoto Murata [IBM Tokyo Research Lab./ International University of Japan]

Dongwon Lee [UCLA / CSD]

Murali Mani [UCLA / CSD]

Abstract

On the basis of regular tree languages, we present a formal framework for XML schema languages. This framework helps to describe, compare, and implement such schema languages. Our main results are as follows: (1) four classes of tree languages, namely "local", "single-type", "restrained competition" and "regular"; (2) document validation algorithms for these classes; and (3) classification and comparison of schema languages: DTD, XML-Schema, DSD, XDuce, RELAX Core, and TREX.

Taxonomy of XML Schema Languages Using Formal Language Theory

1 Introduction
2 Related Work
3 Tree Grammars
3.1 Regular Tree Grammars and Languages
3.2 Local Tree Grammars and Languages
3.3 Single-Type Tree Grammars and Languages
3.4 Restrained-Competition Tree Grammars and Languages
3.5 Summary of Examples
3.6 Expressiveness and Closure
4 Document Validation
4.1 Tree Model vs. Event Model
4.2 DTD validation and their variations
4.3 Variations of Tree Automata
4.4 Non-deterministic algorithms for regular tree grammars
4.5 Summary of Algorithms and their properties
5 Evaluating Different XML Schema Language Proposals
5.1 DTD
5.2 DSD
5.3 XML-Schema
5.4 XDuce
5.5 RELAX Core
5.6 TREX
5.7 Implementations
6 Conclusion