This directory illustrates various approaches to schema creation,
conversion and usage in XML data files.
* The Perl program dtd2xsd converts DTD's to the XSD Schema Language, the official W3C schema
  description language.

* The program Trang (not included here) converts between several other schema description languages.
  In order to use Trang you need to install the Java jar. We created the RELAX NG schema from the
  DTD in ../HelloWorld and subsequently converted it to the XSD format, using these commands:
  
  % java -jar /usr/local/trang/trang.jar -I dtd -O rng ../HelloWorld/greeting.dtd greeting-trang.rng
  % java -jar /usr/local/trang/trang.jar -I rng -O xsd greeting-trang.rng  greeting-trang.xsd

* A small Perl program dtd2xsd.pl can perform *approximate* conversion of DTD to XSD format.
  We used it to generate greeting-dtd2xsd.xsd schema.

* Another approach to schema is automatic generation from instances. We generated a file
  document.xsd from document.xml by using the Exchanger XML Editor (free trial version).

* We use the nXML mode of Emacs to edit our data to take advantage of the automatic validation.
  However, this approach requires that we use the RELAX NG schema. This creates a little bit of a mess, but
  seems to be the best approach for Emacs.