R4/R6 interconverter

[StefanBeyer]

MaLaC-HD could be used to generate static JavaScript code for the R4/R6 maps from the official FML/StructureMap files.

We already evaluated JavaScript support, where we used some R4->R5 maps for our tests. We think that we could provide statically generated JS code for these mappings with only minor adaptions to the engine, as these mappings barely contain FHIRPath and/or complex FML operations.

We could provide an npm-package with the generated code or use a script to generate it here (manually or via CI pipeline). The latter would introduce a Python dependency to the build process, the former would not introduce any additional dependencies apart from the package itself.

If this is an option, I'd go ahead and create an MR for this. Maybe let me know which option would be preferred (npm or script).

[grahamegrieve]

Thanks for this offer. I'm not going to get to this part for a couple of months, but generating static javascript code for the FML is an option. But FML won't do everything that needs to be done, so I have to decide how that might work. When I get to it, I'll investigate and we'll talk

[StefanBeyer]

Sounds good!

We will try to use the time to get the JS support to a level where it should be useful to you.

We also thought about scenarios where FML alone is not sufficient. That's why we plan to implement e.g. hooks so you can override/extend certain aspects of the mapping logic (in the generated code and/or during generation). We are still deciding on how to implement this, so if you encounter any obstacles, just let us know and we'll have a look.