FHIR Chat · New parameter needed!

Currently, if you're using SNOMED (at least in the US) in an IG you have to specify it as the US version of SCT. The way to do this seems to be using a json version of a Parameters resource and adding the path to it in the sushi-config parameters. See here in the IG creation stream

It would be good if this could be done directly in sushi-config.

Chris Moesel (Jan 27 2022 at 18:25):

Help me confirm that I understand the conversation correctly (from the IG creation stream):

You need to specify that you want the US version of SCT by putting a JSON file in your project that is an instance of a Parameters resource (example).
You then need to point to that in IG JSON (or sushi-config.yaml) by adding an IG parameter that says where to find the special Parameters JSON file (example).
It appears that when IG Publisher processes the IG JSON, it adds a special extension to the IG JSON's parameters element that includes the same info as the special Parameters JSON file.
It's not clear if you can skip the Parameters JSON file and directly put the extension in the IG JSON -- but SUSHI doesn't seem to preserve the extension from sushi-config.yaml to the IG JSON file.
We'd like to make this easier w/ FSH/SUSHI one way or another.

David Pyke (Jan 27 2022 at 18:28):

Yes, that file was provided to me but is a straight forward Parameters resource instance
Right. I put the json in my root and point to it from the parameters in the config
Yep. When sushi processes it, it just adds the path to the parameters, it's not until the publisher hits it that the extension exists and is populated
It would be best if I could put the parameter in the Parameter resource directly in the config
Me too.

Elliot Silver (Jan 27 2022 at 18:37):

I suppose I can see a need for include parameter files, but I wonder why the publisher requires them to have particular purpose, and disallows directly including the parameter in the IG resource?

David Pyke (Jan 27 2022 at 18:44):

Because Lloyd is EVIL! EEEEEVVVVILLLLL!!!!!!

David Pyke (Jan 27 2022 at 18:45):

Grahame Grieve (Jan 27 2022 at 19:22):

I don't understand this thread. Why would the IG publisher want to clone all the parameters to the expand operation into being IG parameters? How would that help anyone - other than to mean that people could only use the parameters that the IG publisher specifically supports?

And what extension is this talking about? I don't know of any extension that is relevant here. You name the parameters resource, and then the IG Publisher uses it

David Pyke (Jan 27 2022 at 19:27):

My basic ask is that (somehow) I can set the SNOMED variant to be used in the sushi-config and it creates the ig-parameter extension in IG.definitions would be created automagically, rather than having to have a separate Parameters resource in the root of my build with a reference to it in the sushi-config.

Elliot Silver (Jan 27 2022 at 19:29):

I think--think--what Grahame is saying is that the contents of this file is included in the calls to the terminology server; it isn't actually used by the IG publisher beyond that. And thus, the contents shouldn't be IG parameters.

David Pyke (Jan 27 2022 at 19:30):

That's not right. It's in the final published ImplementationGuide resource as an extension in the .definitions element

Elliot Silver (Jan 27 2022 at 19:30):

Oh well, that should teach me not to try to think.

David Pyke (Jan 27 2022 at 19:34):

Stick with your skillset. Being pretty and sitting in meetings. :stuck_out_tongue_closed_eyes:

Grahame Grieve (Jan 27 2022 at 19:40):

It's in the final published ImplementationGuide resource as an extension in the .definitions element

What extension is this?

David Pyke (Jan 27 2022 at 19:41):

 {
    "extension": [
      {
        "url": "code",
        "valueString": "system-version"
      },
      {
        "url": "value",
        "valueString": "http://snomed.info/sct|http://snomed.info/sct/731000124108"
      }
    ],
    "url": "http://hl7.org/fhir/tools/StructureDefinition/ig-parameter"
  },

Grahame Grieve (Jan 27 2022 at 19:59):

so far as I can tell, the IG publisher knows nothing about this - it must come from the ig resource provided as input to the IG publisher, and it is totally ignored other than being put in this extension when the R4 IG resource is created.