Bi-directional transformation
All XML resources convey information that really has two forms:
- The interchangeable (but otherwise useless), XML form, and
- The parsed, processed, application-internal form.
"Stages 1 and 2" are about the conversion from the interchange form to the useful form. The other transformation -- from the useful form to the interchange form -- is at least equally important.
For reliable, efficient information interchange, the nature of both transformations must be documented.
It would be great if the URI of the vocabulary's "namespace" pointed at a document that had both models, and explained the algorithms involved in transforming information between them.