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In computing, RELAX NG (REgular LAnguage for XML Next Generation) is a schema language for XML, based on Murata Makoto's RELAX and James Clark's TREX.^[1][2][3] A RELAX NG schema specifies a pattern for the structure and content of an XML document. A RELAX NG schema is itself an XML document; however, RELAX NG also offers a popular compact, non-XML syntax.^[4] Compared to other popular schema languages, RELAX NG is relatively simple. It was defined by a committee specification of the OASIS RELAX NG technical committee in 2001 and 2002, and also by part two of the international standard ISO/IEC 19757: Document Schema Definition Languages (DSDL).^[5][6] ISO/IEC 19757-2 was developed by ISO/IEC JTC1/SC34 (ISO/IEC Joint Technical Committee 1, Subcommittee 34 - Document description and processing languages) and published in its first version in 2003.^[7]

Schema examples[link]

Suppose we want to define an extremely simple XML markup scheme for a book: a book is defined as a sequence of one or more pages; each page contains text only. A sample XML document instance might be:

<source lang="xml"> <book>

 <page>This is page one.</page>
 <page>This is page two.</page>

</book> </source>

XML syntax[link]

A RELAX NG schema can be written in a nested structure by defining a root element that contains further element definitions, which may themselves contain embedded definitions. A schema for our book in this style, using the full XML syntax, would be written:

<source lang="xml"> <element name="book" xmlns="http://relaxng.org/ns/structure/1.0">

  <oneOrMore>
     <element name="page">
        <text/>
     </element>
  </oneOrMore>

</element> </source>

Nested structure becomes unwieldy with many sublevels and cannot define recursive elements, so most complex RELAX NG schemas use references to named pattern definitions located separately in the schema. Here, a "flattened schema" defines precisely the same book markup as the previous example:

<source lang="xml"> <grammar xmlns="http://relaxng.org/ns/structure/1.0">

  <start>
     <element name="book">
        <oneOrMore>
           [8]
        </oneOrMore>
     </element>
  </start>
  <define name="page">
     <element name="page">
        <text/>
     </element>
  </define>

</grammar> </source>

Compact syntax[link]

RELAX NG compact syntax is a non-XML format inspired by extended Backus-Naur form and regular expressions, designed so that it can be unambiguously translated to its XML counterpart, and back again, with one-to-one correspondence in structure and meaning, in much the same way that Simple Outline XML (SOX) relates to XML. It shares many features with the syntax of DTDs. Here is the compact form of the above schema:

<source lang="text"> element book {

   element page { text }+

} </source>

With named patterns, this can be flattened to:

<source lang="text"> start = element book { page+ } page = element page { text } </source>

A compact RELAX NG parser will treat these two as the same pattern.

Comparison with W3C XML Schema[link]

Although the RELAX NG specification was developed at roughly the same time as the W3C XML Schema specification, the latter was arguably better known and more widely implemented in both open-source and proprietary XML parsers and editors when it became a W3C Recommendation in 2001. Since then, however, RELAX NG support has increasingly found its way into XML software, and its acceptance has been aided by its adoption as a primary schema for popular document-centric markup languages such as DocBook, the TEI Guidelines, OpenDocument, and EPUB.

RELAX NG shares with W3C XML Schema many features that set both apart from traditional DTDs: data typing, regular expression support, namespace support, ability to reference complex definitions.

Filename extensions[link]

By informal convention, RELAX NG schemas in the regular syntax are typically named with the filename extension ".rng". For schemas in the compact syntax, the extension ".rnc" is used.

See also[link]

• XML schemas
• DTD (Document Type Definition)
• Document Structure Description
• XML Schema (W3C)
• Schematron
• ODD (One Document Does it all)
• SXML

References[link]

External links[link]

• RELAX NG home page
• "The Design of RELAX NG" by James Clark
• RELAX NG tutorial for the XML syntax
• RELAX NG tutorial for the compact syntax
• Design patterns for structuring XML documents
• RELAX NG Book by Eric van der Vlist, released under the GNU Free Documentation License
• Relax NG Reference by ZVON
• RELAX NG Java community projects at java.net
• Sun Multi-Schema Validator (MSV) open-source Java XML toolkit
• Relax NG Compact Syntax validator open-source C program
• XSD to Relax NG Converter Web-based converter

Paul Collier, CBE is a Professor of Economics, Director for the Centre for the Study of African Economies at The University of Oxford and Fellow of St Antony's College. From 1998 – 2003 he was the director of the Development Research Group of the World Bank.^[1]

Life[link]

Collier is a specialist in the political, economic and developmental predicaments of poor countries.^[2] He was brought up in Sheffield where he attended King Edward VII School.^[3] He holds a Distinction Award from Oxford University,^[1] and in 1988 he was awarded the Edgar Graham Book Prize for the co-written Labour and poverty in rural Tanzania: Ujamaa and rural development in the United Republic of Tanzania.^[4]

The Bottom Billion: Why the Poorest Countries are Failing and What Can Be Done About It (ISBN 0195311450), has been compared^[2] to Jeffrey Sachs's The End of Poverty and William Easterly's The White Man's Burden, two influential books, which like Collier's book, discuss the pros and cons of developmental aid to developing countries.

His 2010 book The Plundered Planet^{[5][6][7][8][9]} is encapsulated in his formulas: Nature - Technology + Regulation = Starvation, Nature + Technology - Regulation = Plunder, and Nature + Technology + Regulation (Good Governance) = Prosperity. The book describes itself as an attempt at a middle way between the extremism of "Ostriches" (Denialism, particularly climate change denial) and "Environmental Romanticism" (for example, anti-genetically modified organisms movements in Europe). The book is about sustainable management in relation with the geo-politics of global warming, with an attempt to avoid a global tragedy of the commons, with prime example of overfishing. In it he builds upon a legacy of the economic psychology of greed and fear, from early Utilitarianism (Jeremy Bentham) to more recently the Stern Review.

He was appointed Commander of the Order of the British Empire (CBE) in the 2008 Birthday Honours.^[10] He is a patron of the Media Legal Defence Initiative.

In 2010 and 2011, he was named by Foreign Policy magazine to its list of top global thinkers.^[11][12]

Work[link]

Research topics[link]

• Governance in low-income countries, especially the political economy of democracy
• Economic growth in Africa
• Economics of civil war, aid, globalisation and poverty
• The greed vs grievance debate in international relations

Selected publications[link]

• The Plundered Planet: Why We Must, and How We Can, Manage Nature for Global Prosperity (2010) Oxford University Press ISBN 978-0-19-539525-9.
• Labour and poverty in rural Tanzania: Ujamaa and rural development in the United Republic of Tanzania, Oxford University Press, New York 1991, ISBN 0-19-528315-6.
• The Bottom Billion: Why the Poorest Countries are Failing and What Can Be Done About It. ISBN 0-19-531145-0.
• (with Anke Hoeffler) ‘On economic causes of civil war’ Oxford Economic Papers, vol 50 iss 4, (1998), pp 563–573.
• (with Anke Hoeffler) ‘Greed and grievance in civil war’ Oxford Economic Papers, vol 56 iss 4, (2004), pp 563–595.
• (with Lisa Chauvet and Haavard Hegre) 'The Security Challenge in Conflict-Prone Countries', Copenhagen Consensus 2008 Challenge Paper, (2008).
• Wars, Guns and Votes: Democracy in Dangerous Places, Harper, (March 2009)

Video[link]

• The Royal Economic Society's 2006 Annual Public Lecture, by Coller (Royal Economic Society)
• Interview with Fareed Zakaria on Foreign Exchange
• TED Conference, Paul Collier on "The Bottom Billion"
• TED Conference, Paul Collier's new rules for rebuilding a broken nation

Press[link]

• Review of The Plundered Planet by the Financial Times
• Review of the Bottom Billion by the Financial Times
• Review of the Bottom Billion in The New York Times
• Review of The Bottom Billion by William Easterly in The Lancet
• Samuel Grove, "The Bottom of the Barrel: A Review of Paul Collier's The Bottom Billion: Why the Poorest Countries Are Failing and What Can Be Done about It."

See also[link]

	Environment portal
	Politics portal
	Economics portal

• Environmental politics
• Good Governance
• Tanzania

References[link]

External links[link]

• Paul Collier's home page at Oxford University
• Links to downloadable research papers on Africa, Aid, Conflict, Political Economy and other topics
• Interview with Paul Collier by J. Tyler Dickovick
• Interview with the Oxonian Review in March 2009
• Video of recent talk at Oxford University - "The Bottom Billion"
• TED Talks: Paul Collier shares 4 ways to help the "bottom billion" at TED in 2008