21. Platform - Generating UIs from XML

It is not a new idea to treat a UI as a transformation of an XML document

Most people use XML instance documents as a template or example for the data entry form or UI display

But instances don't suffice in situations where there are choices in the content model and the instance doesn't contain all the information needed for validation

Using XML schemas as the starting point solves these two problems

However, we have to solve the harder problem of using schemas that are assembled from libraries of schemas to exploit the reuse of information represented in BABL