Editing XML (section)

=== DSDL and other schema languages ===
[[DSDL]] (Document Schema Definition Languages) is a multi-part ISO/IEC standard (ISO/IEC 19757) that brings together a comprehensive set of small schema languages, each targeted at specific problems. DSDL includes [[RELAX NG]] full and compact syntax, [[Schematron]] assertion language, and languages for defining datatypes, character repertoire constraints, renaming and entity expansion, and namespace-based [[routing]] of document fragments to different validators. DSDL schema languages do not have the vendor support of XML Schemas yet, and are to some extent a grassroots reaction of industrial publishers to the lack of utility of XML Schemas for [[publishing]].

Some schema languages not only describe the structure of a particular XML format but also offer limited facilities to influence processing of individual XML files that conform to this format. DTDs and XSDs both have this ability; they can for instance provide the [[infoset]] augmentation facility and attribute defaults. RELAX NG and Schematron intentionally do not provide these.