We are now in a better position to define somewhat formally define the underlying FHIR data types. That is to say, not the "on the wire" representational types, but the types of FHIR objects themselves (as, for instance, they might be represented in FHIR implementation).
more ...Long time, no updates. I discovered soon after I thought I was complete, that I had missed an important FHIR concept. In the documentation for resource formats, there is a mention of "an element which can have one of a several different types". A wild type example is found in the Extensions that I struggled with; the Procedure resource contains two examples (site and performed).
I've wired up extensions into values and resources, completing the journey. At this point, I've completed construction of, and JSON serialization of, FHIR resources and included components, built from an underlying set of algebraic data types. (I haven't deserialized yet, so there's clearly a lot more to know).
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