FHIR Chat · Use of Library Resource · fhirpath

Stream: fhirpath

Topic: Use of Library Resource

Brian Postlethwaite (May 06 2020 at 20:57):

Anyone used the library resource to contain fhirpath expressions?
@Bryn Rhodes I've seen the examples that show including .cql files encoded in there, what I'm looking for is including an expression datatype used as an extension property in there.
As the expression itself is the content...
(Happy for the name and description to come out into the real props)

          <valueExpression>
            <description value="Practitioner from Context's Medicare Provider number" />
            <name value="ContextPractitionerProviderNumber" />
            <language value="text/fhirpath" />
            <expression value="%LaunchPractitioner.identifier.where(system='http://ns.electronichealth.net.au/id/hi/prn').first().value" />
          </valueExpression>

Or does this text need to be base64 encoded into the attachment content data?

Bryn Rhodes (May 06 2020 at 21:30):

I've seen suggestions for using multiple content elements in this way, but that would still require base64 encoding of the expressions. If I understand what you're suggesting, it is to actually use extensions to add the expressions using the Expression data type, and then be able to reference those by name. I like that approach, and it would be a straightforward profile to define, then it would be referenced with a canonical, something like: http://fhir.org/guides/example/Library/FHIRPathCollection#ContextPractitionerProviderNumber, yes?

Bryn Rhodes (May 06 2020 at 21:31):

The only thing that feels a little off about that is how would a system know to interpret the anchor part of that URL as a reference to an extension by the name.

Bryn Rhodes (May 06 2020 at 21:31):

Other than that that's the behavior we would prescribe, of course :)

Brian Postlethwaite (May 06 2020 at 23:23):

I'll try it out just base64 ing the expression into some resources and see how it goes.

Last updated: Apr 12 2022 at 19:14 UTC