*Homepage:* http://www.w3.org/XML/

XML is the Extensible Markup Language, a format for the exchange of 
structured data.

XML, which is a simplified subset of SGML, was designed as a universal
structured document format, but it is general enough to represent
arbitrary structured data in a text file. The format of a XML file is
given separately in a DocumentTypeDefinition (DTD) or another SchemaLanguageForXML. The XML syntax is quite verbose and not (necessarily) meant to be read by humans. XML
imposes a hierarchical tree structure on the data. GraX, GXL, and RDF
all use XML for data exchange. (Quoted from ExchangeFormatBibliography) 

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There are a number of systems for processing and transforming XML documents

	* ExtensibleStylesheetLanguage (XSL)
	* HaXml
	* [[XMLambda]]
	* [[XDuce]]
	* Stratego [[Tools.XmlTools][xml-tools]]
	* DMSSoftwareReengineeringToolkit
	* [[TL]] - Template Language using XML and Java

There are also other ExchangeFormats, some of which are based on XML.

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For parsing, three approaches are frequently used:
	* The SimpleAPIforXML
	* The DocumentObjectModel
	* XMLPullParsing
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Concerning the Hyper Text Markup Language HTML we are
all so familiar with,
there is a redefinition of HTML-4 into XHTML1, 
which makes HTML really conform to the XML standard.
See http://www.w3.org/TR/xhtml1/ 

-- ArieVanDeursen (thnx, ErnstJanVerhoeven).
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CategoryDataFormat | Contributions by EelcoVisser, ArieVanDeursen, ErnstJanVerhoeven, MartinBravenboer