RELAX NG home page

Last updated: 2014-02-25

Contents

RELAX NG is a schema language for XML. The key features of RELAX
NG are that it:

• is simple
• is easy to learn
• has both an XML syntax and a compact non-XML syntax
• does not change the information set of an XML document
• supports XML namespaces
• treats attributes uniformly with elements so far as possible
• has unrestricted support for unordered content
• has unrestricted support for mixed content
• has a solid theoretical basis
• can partner with a separate datatyping language (such W3C XML Schema Datatypes)

The RELAX NG specifications have been developed within OASIS by the RELAX NG
Technical Committeee. RELAX NG is also an
International Standard (ISO/IEC 19757-2).
It is Part 2 of ISO/IEC 19757 DSDL (Document Schema Definition Languages),
which is maintained by ISO/IEC
JTC1/SC34/WG1.
RELAX NG was based on TREX designed by James
Clark and RELAX Core designed by
MURATA Makoto.

project for extending RELAX NG has started
in ISO/IEC JTC1/SC34/WG1. RELAX NG Version 2 is likely to become a new part of ISO/IEC 19757, while RELAX NG Version 1 continues to exist
as Part 2 of ISO/IEC 19757.

Tutorials

RELAX NG Tutorial (errata), OASIS
Committee Specification, 3 December 2001. Tutorial for RELAX NG using
the XML syntax. More recent, but not officially approved Working Draft, 26 March 2003 also
available

RELAX NG Compact Syntax
Tutorial, OASIS Working Draft, 26 March 2003. Tutorial for RELAX
NG using the compact syntax, not assuming prior knowledge of XML
syntax.

Specifications

RELAX NG Specification (errata), OASIS
Committee Specification, 3 December 2001. Definitive specification
for RELAX NG using the XML syntax.

ISO/IEC
19757-2:2003 Document Schema Definition Language (DSDL) — Part 2:
Regular-grammar-based validation — RELAX NG. ISO version of
RELAX NG Specification; the technical content of this is identical to
the OASIS Committee Specification, but there are editorial changes to
satisfy ISO rules.

RELAX NG Compact Syntax, OASIS
Committee Specification, 21 November 2002. Definitive specification
for the compact syntax in terms of the XML syntax.

ISO/IEC 19757-2:Amd1
Document Schema Definition Language (DSDL) — Part 2: Regular-grammar-based validation — RELAX NG — Amendment 1: Compact Syntax.
ISO version of the RELAX NG Compact Syntax; RELAX NG Compact Syntax; the technical content of this is identical to the OASIS Committee Specification, but there are editorial changes to satisfy ISO rules.

ISO/IEC 19757-2:2008 Document Schema Definition Language (DSDL) — Part 2:
Regular-grammar-based validation — RELAX NG. The second edition is created by consolidating the first edition and Amd1:2006 and then fixing some bugs.

RELAX NG DTD
Compatibility, OASIS Committee Specification, 3 December
2001. Defines annotations and datatypes that support some of the
features from XML 1.0 DTDs not supported directly by RELAX NG.

Guidelines for using W3C XML Schema
Datatypes with RELAX NG, OASIS Committee Specification, 7
September 2001.

Books

RELAX NG is a book written by Eric van der Vlist. It is freely available on the Web.

Other documents

XML Matters: Kicking back with RELAX NG, Part
1, Part
2, Part
3, David Mertz, IBM developerWorks. Series of articles
introducing RELAX NG.

Relax
NG, Compared, Eric van der Vlist, XML.com. Article comparing RELAX
NG and W3C XML Schema.

RELAX NG’s
Compact Syntax, Michael Fitzgerald, XML.com. Article introducing
RELAX NG using the compact syntax.

XML and the
IETF: Making the case for RELAX NG, Michael Smith, xmlhack.
Reports on arguments advanced as to why RELAX NG is preferable to W3C
XML Schema, in the context of IETF discussions on XML.

The
Design of RELAX NG, James Clark. Paper discussing the thinking
behind the design of RELAX NG.

ZVON RELAX
Reference, Jiri Jirat. On-line reference guide to RELAX NG.

Notes on
implementing RELAX NG, James Clark. Provides some information on
how to implement a RELAX NG validator.

Validators

Jing,
RELAX NG validator. Supports both XML and compact syntaxes. Can be
used as a library for validation with any SAX2 parser. Implemented in
Java. Written by James Clark. Open source (BSD license).

RNV Relax NG Compact Syntax validator in ANSI C (under BSD license)

Libxml2, the XML C library
for Gnome. Recent versions of libxml2 (at least 2.5.5) support RELAX
NG validation. Only the XML syntax is supported. Libxml2 is included
in most modern Linux distributions. Implemented in C. Written by
Daniel Veillard. Open source (MIT license).

MSV,
Sun Multi-Schema XML Validator. Validates RELAX NG. Supports XML
syntax only. Also supports other schema languages including W3C XML
Schema. Can be used as a library for validation and for accessing the
schema. Implemented in Java. Written by Kohsuke KAWAGUCHI. Open
source (BSD license).

Bali, RELAX
NG validator compiler. Reads a RELAX NG schema and produces a
validator that can validate documents with the given schema. Compiler
uses MSV and is implemented in Java. Generated validator can be in
Java, C++ for Win32 (using MSXML4) or C#. Written by Kohsuke
KAWAGUCHI. Open source (BSD license).

Tenuto, RELAX
NG validator for .NET. Implemented in C#. Open source (BSD
license).

XVIF, XML
Validation Interoperability Framework. Proof of concept
implementation of the idea of embedding XML processing pipelines in a
grammar. Includes a partial implementation of RELAX NG. Implemented
in Python. Written By Eric van der Vlist. Open source (MPL).

RelaxngValidatingReader,
.NET XmlReader that validates using RELAX NG. Implemented in
C#. Included in Mono. Written
by Atsushi Enomoto. Open source (public domain).

On-line validator. It
supports both RELAX NG Compact and XML syntax.

ManekiNeko,
Xerces parser configuration that supports RELAX NG validation. Puts
an XNI wrapper around Jing. Implemented in Java. Written by Andy
Clark. Open source (Apache-style license).

Sun
MSV Schematron add-on, allows a document to be validated against a
RELAX NG grammar and also against Schematron
constraints embedded as annotations in the RELAX NG. Uses MSV.
Implemented in Java. Written by Kohsuke KAWAGUCHI. Open source (BSD
license).

Topologi XML Judge
, a Windows application for validating an XML document
against a variety of schema languages, including RELAX NG. Uses
VBRELAXNG.

Conversion tools

Trang,
multi-format schema converter based on RELAX NG. Trang supports the
following languages: RELAX NG (both XML and compact syntax), XML 1.0
DTDs, W3C XML Schema. A schema written in any of the supported schema
languages can be converted into any of the other supported schema
languages, except that W3C XML Schema is supported for output only,
not for input. Trang can also infer a schema from one or more example
XML documents. Trang aims to produce human-understandable schemas; it
tries to preserve all aspects of the input schema that may be
significant to a human reader, including the definitions, the way the
schema is divided into files, annotations and comments. Uses Jing.
Implemented in Java. Written by James Clark. Open source (BSD
license).

Sun
RELAX NG Converter. The Sun RELAX NG Converter is a tool to
convert schemas written in various schema languages to their
equivalent in RELAX NG. It supports schemas written in XML DTD, RELAX
Core, RELAX namespace, TREX, W3C XML Schema, and RELAX NG itself. It
does aims only to produce a RELAX NG schema that is equivalent to the
input schema in the sense that it validates the same documents as the
input schema; it does not aim to preserve information that is not
significant for validation such as the use of definitions. Based on
MSV. Implemented in Java. Written by Kohsuke KAWAGUCHI. Open source
(BSD license).

XSD to RelaxNG. web-based converter from W3C XML Schema to RELAX NG. The user
types a WXS schema in this web form, and
gets a RELAX NG schema with the convert button. The conversion is done by an XSLT stylesheet.

InstanceToSchema, a
tool to generate a RELAX NG schema from XML instances. Implemented in
Java. Written by Didier Demany. Open source (BSD license).

rng2srng, a
tool to convert RELAX NG (XML or compact syntax) into the simple
syntax. The simple syntax is a minimal subset of the XML syntax
defined by the RELAX NG specification, into which any RELAX NG schema
can be transformed. Uses Jing. Implemented in Java. Written by
Kohsuke KAWAGUCHI. Open source (BSD license).

NekoDTD,
DTD to instance converter. Uses the Xerces Native Interface (XNI) to
convert DTD into an XML document, which can then be converted into
other formats. Includes XSLT stylesheets to convert XML output format
into RELAX NG. Implemented in Java. Written by Andy Clark. Open source
(Apache-style license).

rnc2rng,
converter from RELAX NG Compact Syntax to RELAX NG XML Syntax.
Implemented in Python. Originally written by David Mertz, now maintained
by Dirkjan Ochtman. Open Source (public domain).

Simplification of RelaxNG schemas. A web-based simplifier of RELAX NG schemas. It is based on an XSLT stylesheet written by Eric van der Vlist.

Code generators

Relaxer, schema compiler. Can
generate a collection of Java classes from a RELAX NG schema along
with code to create instances of those classes from XML and
vice-versa. Provides many other features useful for processing data
described by a RELAX NG schema. Uses MSV. Implemented in
Java. Written by ASAMI Tomoharu. Open source (GPL for compiler, BSD
license for generated code, LGPL for runtime libraries).

RelaxNGCC, RELAX NG
Compiler Compiler. Tool for generating Java source code from a given
RELAX NG grammar. By embedding code fragments in the grammar like yacc
or JavaCC, you can take appropriate actions while parsing valid XML
documents against the grammar. Uses MSV. Implemented in Java. Written
by Daisuke OKAJIMA and Kohsuke KAWAGUCHI. Open source (GPL for
compiler, public domain for generated code).

XML editors

Stylus Studio now supports RELAX NG!

Firedocs is a browser based wysiwyg-xml-editor
that has schema-driven auto-complete and uses Jing for validation.
Licence: ASL 2.0

xmloperator, an XML
editor, suitable for editing data oriented documents. Allows any
RELAX NG schema to be used to guide editing. Implemented in Java.
Written by Didier Demany. Open source (BSD license).

Topologi
Collaborative Markup Editor, XML editor including support for
RELAX NG. Commercial.

XML editor.
Provides validation and completion using RELAX NG. Supports both XML
and compact syntaxes. Multiplatform, implemented in
Java. Commercial.

XMLBlueprint XML Editor
Provides validation and completion using RELAX NG. Commercial.

XMLBuddy Pro
Provides validation and completion using RELAX NG. Commertical.

RNGEdit (in Japanese)

Other software

nXML mode.
nXML mode is an addon for GNU Emacs, which makes GNU Emacs into a powerful XML editor.

RNC Emacs Mode.
A small emacs mode for editing RELAX NG schemas in the compact
syntax. Written by David Rosenborg. Open source (BSD license).

RNC SAX Parser. SAX2
parser for the RELAX NG Compact syntax. It will parse a compact syntax
schema and send events to a content handler as if it was reading a
RELAX NG schema in the XML syntax. Implemented in Java. Written by
David Rosenborg. Open source (BSD license).

RNC
Vim syntax definition. It allows the Vim editor to do syntax highlighting for
RELAX NG compact syntax schemas. Written by Hans Fugal. Open source.

RELAX NG datatype
interface. Interface between RELAX NG validators and datatype
libraries. Java, .NET and COM versions available. Written by James
Clark and Kohsuke KAWAGUCHI. Open source (BSD license).

Sun
XML datatypes library. Implementaton of the datatypes of XML
Schema Part 2. Supports the RELAX NG datatype interface. Used by MSV.
Implemented in Java. Written by Kohsuke KAWAGUCHI. Open source (BSD
license).

Sun
XML Instance Generator. Tool to generate valid and invalid
instances from schemas. It can be used for generating test cases for
XML applications that need to conform to a particular schema. Uses
MSV. Implemented in Java. Written by Kohsuke KAWAGUCHI. Freely
downloadable, but not open source.

RelaxMeter, a
tool to check whether a RELAX NG grammar is ambiguous. Uses
MSV. Implemented in Java. Written by Kohsuke KAWAGUCHI. Open source
(MIT license).

Schema simplifier in XSLT. An XSLT stylesheet to perform the
RELAX NG syntax simplification described in the RELAX NG
specification. Written by Eric van der Vlist.

incelim.
This set of XSLT stylesheets take a Relax NG grammar in XML syntax, expand all includes and externalRefs, and optionally replace references to text, empty, or notAllowed with the patterns. The result is a ‘compiled’ schema convenient for distribution. Written by David Tolpin.

RELAX NG Object Model. RNGOM is an open-source Java library for parsing RELAX NG grammars. It is based on Jing, but exposes schemas to programmers. Written by Kohsuke Kawaguchi.

Schema to web form. A web-based interface for transforming a RELAX NG schema into an XHTML form.

New!XSLT 3.0

Citation Style Language (CSL) uses RELAX NG schemas.

Atom Syndication Format

Google Data API (Calendar List Feed Schema, for example)

Adobe InDesign IDML

Open Publication Structure(OPS), IDPF

Open Packaging Format
(OPF), IDPF

Open Container Format (OCF), IDPF

RELAX NG 1.0, from the RELAX NG
Specification, with errata applied.

TEI P5

DocBook,
Norman Walsh.

XHTML,
James Clark.

XSLT 1.0,
James Clark.

SMBmeta 0.1 on RELAX-NG, Yutaka Furubayashi

P3P 1.0 on RELAX-NG, Yutaka Furubayashi

MathML 2.0 on RELAX-NG, Yutaka Furubayashi

SVG 1.1 on RELAX-NG, Yutaka Furubayashi

W3C XML
Schema, Jeni Tennison. An update by Peter A. Bigot.

VoiceXML,
Kohsuke KAWAGUCHI.

XML-DSig,
Joseph Reagle.

XENC,
Joseph Reagle.

RDF,
James Clark, David Beckett.

IBTWSH,
John Cowan.

ODF RELAX NG schemas for ODF 1.0 and ODF 1.1 are available.

OOXML Ecma-376 2nd edition Parts 1, 2, and 4 includes non-normative RELAX NG schemas.

Test
suite, James Clark. Unofficial test suite using the XML syntax.

OASIS
RELAX NG TC home page

Robin Cover’s
RELAX NG page

James Clark’s
RELAX NG page

Kohsuke KAWAGUCHI’s RELAX
NG page

Yutaka
Furubayashi’s RELAX NG page

This web page is maintained by MURATA Makoto.