Namespace-based Validation Dispatching Language (NVDL) is an XML schema language for validating XML documents that integrate with multiple namespaces.
Much of the work on NVDL is based on the older Namespace Routing Language.
The purpose of NVDL is to provide that linkage, based on namespaces.
Rules include a specific namespace and a mode setting.
NVDL recognizes the mode as a particular piece of state that changes as the document is processed.