description: Smart Guidelines (required) string extension for use in a complex extension package_name: smart.who.int.base derivation: constraint name: SGString type: Extension elements: extension: {index: 0} url: pattern: {type: Uri, value: 'http://smart.who.int/base/StructureDefinition/SGString'} index: 1 value: mustSupport: true choices: [valueString] index: 3 valueString: {type: string, mustSupport: true, choiceOf: value, index: 4} package_version: 0.2.0 extensions: {} class: extension kind: complex-type url: http://smart.who.int/base/StructureDefinition/SGString base: http://hl7.org/fhir/StructureDefinition/Extension version: 0.2.0 required: [valueString, value]