Support for resolve()

[vadi2]

It would be nice if resolve() was supported for references that are within the Bundle you are operating on.

[vadi2]

I haven't got the bandwidth to add resolve natively, but in case anyone is looking for a naive implementation to use externally, this works well:

def evaluate_with_resolve(bundle, fhirpath):
    if '.resolve()' not in fhirpath:
        return evaluate(bundle, fhirpath)
        
    path_segments = fhirpath.split('.resolve()')
    current_result = evaluate(bundle, path_segments[0])
    
    for segment in path_segments[1:]:
        if not current_result:
            return None
        reference_id = current_result[0]
        if not reference_id:
            return None
        # Find referenced resource in bundle
        referenced_resource = next(
          (entry['resource'] for entry in bundle['entry'] 
          if entry.get('fullUrl') == reference_id),
          None)

        if not referenced_resource:
            return None
        current_result = evaluate(referenced_resource, segment.lstrip('.'))
    return current_result

[ruscoder]

Hi @vadi2, thanks for posting your solution, it's useful feature.

The only addition from my side to this feature - it should follow the specification of resolving references, in that case reference 'Patient/123' should be also resolved into the entry with fullUrl http://example.com/fhir/Patient/123.

[ruscoder]

The fhirpath specification says nothing about how exactly url's should be resolved.

For me, it looks logical to have a Bundle as context, and use it like:
evaluate(bundle, 'entry.resource.ofType(Patient).managingOrganization.resolve()')
should return all patients' organizations.

[axelv]

FYI: we do this by patching the invocation table:

from fhirpathpy.engine.invocations import invocation_registry

# add custom resolve fn to the invocations_register
invocation_registry["resolve"] = {"fn": resolve, "arity": {0: []}}
evaluate({...},  "Patient.subject.resolve()")

But not sure if it's ok to use invocation_registry directly