XDML - an extensible markup language and processor for XDM
Hans-Jürgen Rennau, David A. Lee · Balisage series on markup technologies · 2011
XDML is a set of rules how XDM values can be built which are more useful entities as compared to ordinary XDM values. The key idea is to insert into the XDM values control information which guides the interpretation and processing of the data. In particular, it structures the XDM value into named parts and associates these parts with metadata. The control information is evaluated by an XDML processor, which reports and processes the data accordingly. The processing of a part is organized as the execution of operations which the control data bind to the part, but whose actual invocation depends on API calls of the XDML user. The bindings are represented by request messages which encode the actual input to operations selected from an extensible library of available "XDML operations". The operation bindings of a part can be regarded as a specific interface dynamically attached to the data of the part. The net result of this approach is to enable the creation of self-describing XDM values: they encode the way how they are presented to applications, as well as how they should or might be processed. This means that the XDM producer - e.g. XQuery programs - can emit "rich" data whose downstream processing is significantly simplified.