FHIR-specific functions

The following functions are defined in the FHIR specification as additional FHIRPath functions for use with FHIR data.

The notation used to describe the type signature of each function is as follows:

[input type] -> [function name]([argument name]: [argument type], ...): [return type]

extension

collection<Element> -> extension(url: String) : collection<Extension>

Filters the input collection to only those elements that have an extension with the specified URL. This is a shortcut for .extension.where(url = string).

Example:

Patient.extension('http://hl7.org/fhir/StructureDefinition/patient-birthPlace')

resolve

collection<Reference> -> resolve() : collection<Resource>

For each Reference in the input collection, returns the resource that the reference points to.

note

Pathling has a limited implementation of resolve(). It supports type checking with the is operator but does not perform actual resource resolution or allow traversal of resolved references.

memberOf

collection<Coding|CodeableConcept> -> memberOf(valueSetUrl: String) : collection<Boolean>

The memberOf function can be invoked on a collection of Coding or CodeableConcept values, returning a collection of Boolean values based on whether each concept is a member of the ValueSet with the specified url.

For a CodeableConcept, the function will return true if any of the codings are members of the value set.

note

The memberOf function is a terminology function, which means that it requires a configured terminology service. See Terminology functions for details.

subsumes

collection<Coding|CodeableConcept> -> subsumes(code: Coding|CodeableConcept) : collection<Boolean>

This function takes a collection of Coding or CodeableConcept elements as input, and another collection as the argument. The result is a collection with a Boolean value for each source concept, each value being true if the concept subsumes any of the concepts within the argument collection, and false otherwise.

Example:

Patient.reverseResolve(Condition.subject).code.subsumes(http://snomed.info/sct|770581008)

note

The subsumes function is a terminology function, which means that it requires a configured terminology service. See Terminology functions for details.

subsumedBy

collection<Coding|CodeableConcept> -> subsumedBy(code: Coding|CodeableConcept) : collection<Boolean>

The subsumedBy function is the inverse of the subsumes function, examining whether each input concept is subsumed by any of the argument concepts.

Example:

Patient.reverseResolve(Condition.subject).code.subsumedBy(http://snomed.info/sct|73211009)

note

The subsumedBy function is a terminology function, which means that it requires a configured terminology service. See Terminology functions for details.