A communiqué from Rick Jelliffe announces the availability of the Topologi Schematron Validator tool. The Schematron Validator user interface "supports validation of multiple files, and store/recall of locations to allow validation of chains of transformations. As well as Schematron validation, the tool also supports DTDs and W3C XML Schemas validation. Schematron schemas can be embedded in W3C XML Schemas schemas to augment them. The tool is highly reconfigurable. It also provides XSLT transformations, and the automatic generation of Topic Maps and RDF (beta). It allows simple editing and a variety of different viewers, including text, single-pane web-browser and double-pane web-browser. The Topologi Schematron Validator comes with schemas for CALS tables, NITF, QAML, RDDL, RDF, RSS, Schematron, SOAP, SMIL, XHTML WAI, WSDL, XLink, and XTM. These are all open source and readily accessible. The tool will be useful for anyone with document which have constraints that cannot be expressed in schema languages such as DTDs, XML Schemas, RELAX, etc. and for creating friendly validators for files. Educators may find it convenient for teaching XML classes. Experimenters will appreciate the tool's configurability." The tool is available for no cost from the Topologi web site. The developers have provided an online version of the Schematron Validator manual, together with screen shots.
Schematron description: "The Schematron, 'a simple and powerful Structural Schema Language,' is an 'XML Structure Validation Language using Patterns in Trees.' The Schematron differs in basic concept from other schema languages in that it not based on grammars but on finding tree patterns in the parsed document. This approach allows many kinds of structures to be represented which are inconvenient and difficult in grammar-based schema languages. If you know XPath or the XSLT expression language, you can start to use The Schematron immediately. The Schematron allows you to develop and mix two kinds of schemas: (1) Report elements allow you to diagnose which variant of a language you are dealing with. (2) Assert elements allow you to confirm that the document conforms to a particular schema. The Schematron is based on a simple action: First, find a context nodes in the document (typically an element) based on XPath path criteria; Then, check to see if some other XPath expressions are true, for each of those nodes. The Schematron can be useful in conjunction with many grammar-based structure-validation languages: DTDs, XML Schemas, RELAX, TREX, etc. You can even embed a Schematron schema inside an XML Schema <appinfo> element..."