class Attribute:
  key: Coding 1..1
  composition: ContextGroup | AttributeComponent 1..1

class ContextGroup:
  path: str 1..1
  components: ContextGroup | AttributeComponent 1..*

# Not really usable ATM since references are handled as linked criteria
# class ReferenceGroup(ContextGroup):    
#  type: RetrievableType 1..1 # Type that is retrievable in CQL, e.g. all (retrievable) FHIR Types as defined by the ELM FHIR model info

class AttributeComponent:
  type: str 1..1
  path: str 1..1 # Relative path to criterion value
  cardinality: LiteralStr["single", "many"] 1..1
  operator: str 1..1
  valueType: str 0..1
  values: Any 0..* # Similar to polymorphic types in FHIR. Is empty if the values are user input