FHIR Chat · fhir-type extension · fhir/infrastructure-wg

Stream: fhir/infrastructure-wg

Topic: fhir-type extension

Josh Mandel (Jan 19 2022 at 18:44):

From WGM discussion: I see this fhir-type extension is used in cases where the element definition type code is something like http://hl7.org/fhirpath/System.String (as per the example at https://build.fhir.org/patient.profile.json.html) -- but what are these fhirpath values, and if we are using them in the core specification it is there a reason we don't include them in the (admittedly extensible) ValueSet bound at http://build.fhir.org/elementdefinition-definitions.html#ElementDefinition.type.code ?

Bryn Rhodes (Jan 19 2022 at 23:07):

They are a reference to the FHIRPath primitive types, there's some discussion on it here: https://hl7.org/fhir/fhirpath.html#types

Josh Mandel (Jan 19 2022 at 23:08):

Is there a reason not to include them in http://build.fhir.org/valueset-defined-types.html, given that we're leaning on them in core?

Bryn Rhodes (Jan 19 2022 at 23:08):

The System.String part is defined in the FHIRPath specification, and the hl7.org/fhirpath URI is defined here: https://hl7.org/fhirpath/#uri-and-media-types

Bryn Rhodes (Jan 19 2022 at 23:09):

I'm not sure why we don't include them in that value set.

Bryn Rhodes (Jan 19 2022 at 23:09):

I don't see a reason we couldn't, other than we'd need to change the definition of the value set (and the corresponding codesystem) from "types _defined_ in the FHIR specification" to "types _used_ in the FHIR specification"

Bryn Rhodes (Jan 19 2022 at 23:10):

And perhaps the thing to do would be to define the "FHIRPathTypes" code system and value set, and then bind that element extensibly to a grouper of both.