Advanced approaches to XML document validation

Relaxed is an open-source automated tool that provides support for validation of XML documents using predefined or custom compound languages. For example, it can validate documents that use combinations such as XHTML 1.0 + MathML 2.0 + SVG 1.1, testing for conformance with constraints expressed in Relax NG, Schematron, and other schema languages, under the control of NVDL (Namespace-based Validation Dispatching Language). In addition to the maintenance of these schemas, the Relaxed project also includes an extensible validation engine written in Java. Examples that demonstrate the usefulness and practicality of combining multiple kinds of validation and constraint expressions in a convenient automated framework are discussed.