RELAX NG coding requirements

This section explains how to implement RNG-based document-type shells, specializations, and element-configuration modules (constraints and expansions).

If you plan to generate DTD- or XSD-based modules from RELAX NG modules, avoid RELAX NG features that cannot be translated into DTD or XSD constructs. Such features include lexical patterns for attributes and elements, interleave patterns, and context-specific patterns for content models or attribute lists.

When RELAX NG is used directly for DITA document validation, the document-type shells for those documents can integrate constraint modules that use the full power of RELAX NG to enforce constraints that cannot be enforced by DTDs or XSDs.