description: An expression that returns a boolean value for whether to enable the item. package_name: hl7.fhir.uv.sdc derivation: constraint name: EnableWhenExpressionExtension type: Extension elements: url: type: uri pattern: {type: Uri, value: 'http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-enableWhenExpression'} index: 0 valueExpression: {type: Expression, index: 1} package_version: 2.7.0 class: extension kind: complex-type url: http://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-enableWhenExpression base: http://hl7.org/fhir/StructureDefinition/Extension version: 2.7.0