> I don't understand your concern with the possibility of a FHIR Shorthand expression being undecidable. This just isn't a problem in any real world system.
My discovery of the format being undecidable came with the experience of building a system designed to ingest and interop data for an entire state (Victoria) during the construction of Australia's MyHealthRecord [0], which I would classify as a "real world system".
It was just one of the many edge cases I found with the standards, and led me to believe that no, it isn't possible to normalize the data that these standards are supposed to encode. And no, there is no way in hell that you can get many thousands of practitioners all to follow a single IG.
It's such a lovely set of standards that MHR developed the HIPS Middleware Standard [1] to sit between all HL7 documents and the developer interfaces of MHR.
Just because it's possible in theory to construct an undecidable FHIR Shorthand expression doesn't mean that's a real problem in practice. Could you give us some specific details about how that issue impacted MyHealthRecord? Have you created a Jira issue and brought it up to the FHIR Infrastructure Work Group, or registered a negative on the latest IG ballot? I'm sure they'd like to know and would try to find a solution.
A few edge cases are really not a serious concern. There are many organizations using these standards. In fact in the USA we're getting thousands of practitioners to follow a single IG right now because they're mandated to by federal regulation. Of course there will be some technical challenges and defects but those will be gradually resolved over time. And in practice there won't be thousands of independent implementations; instead a few vendors will implement the specifications and then the provider organizations will use that software.
HIPS appears to be a tool for doing patient index matching, and for converting between legacy HL7 V2 Messaging and CDA formats. That's useful functionality, but doesn't indicate any sort of problem with FHIR.
Instead of complaining about the standards I would encourage you to get actively involved in improving them. The standards development process is totally open and transparent, and the work groups welcome new members who want to contribute in a positive way.
Yeah... This kind of overly defensive and dismissive response is precisely the reason that HIPS exists, and why MHR gave up on speaking with the standards bodies. The complaints by a federal project are a serious concern, and so are edge cases that they hit, because HL7 seems to have more edges than a razor blade.
MHR is five years old. These problems do not get resolved over time. An undecidable FHIR is a problem in practice, because that's where it was discovered to be a problem. It's not a defect that gets resolved because a few vendors implement software that gets widely used - it's a defect because it'll get resolved differently between those vendors. A data format should be a regular language.
HIPS exists so that the MHR devs don't have to see a single HL7 document of any kind - because the formats are awful, in every possible way. I'm sorry, but I have nothing good to say about working with HL7, both the standards and the working groups.
My discovery of the format being undecidable came with the experience of building a system designed to ingest and interop data for an entire state (Victoria) during the construction of Australia's MyHealthRecord [0], which I would classify as a "real world system".
It was just one of the many edge cases I found with the standards, and led me to believe that no, it isn't possible to normalize the data that these standards are supposed to encode. And no, there is no way in hell that you can get many thousands of practitioners all to follow a single IG.
It's such a lovely set of standards that MHR developed the HIPS Middleware Standard [1] to sit between all HL7 documents and the developer interfaces of MHR.
[0] https://www.myhealthrecord.gov.au/
[1] https://developer.digitalhealth.gov.au/specifications/implem...