description: 'An expression that provides an alternative definition of the content of the value set (compose). There are two different ways to use this expression extension: If both an expression (this extension) and a compose element is present, the compose is understood to make the same statement as the expression. If there is no compose, the expression is the only definition of the value set and the ValueSet definition (compose) can only be evaluated by a system that understands the syntax used in the expression.'
package_name: hl7.fhir.uv.extensions.r3
derivation: constraint
name: VSExpression
type: Extension
elements:
  extension:
    array: true
    index: 0
    slicing:
      rules: open
      ordered: false
      discriminator:
      - {path: url, type: value}
      min: null
      slices:
        _datatype:
          match: {url: null}
          schema:
            type: Extension
            short: DataType name 'Expression' from R5
            url: h
            index: 1
            elements:
              value:
                pattern: {type: String, value: Expression}
                choices: [valueString]
                index: 3
              valueString:
                type: string
                pattern: {type: String, value: Expression}
                choiceOf: value
                index: 4
            required: [valueString, value]
        description:
          match: {url: description}
          schema:
            short: Natural language description of the condition
            index: 5
            extensions: {}
            elements:
              extension: {index: 6}
              url:
                pattern: {type: Uri, value: description}
                index: 7
              value:
                choices: [valueString]
                index: 9
              valueString: {type: string, choiceOf: value, index: 10}
            required: [valueString, value]
        name:
          match: {url: name}
          schema:
            short: Short name assigned to expression for reuse
            index: 11
            extensions: {}
            elements:
              extension: {index: 12}
              url:
                pattern: {type: Uri, value: name}
                index: 13
              value:
                choices: [valueCode]
                index: 15
              valueCode: {type: code, choiceOf: value, index: 16}
            required: [valueCode, value]
        language:
          match: {url: language}
          schema:
            short: text/cql | text/fhirpath | application/x-fhir-query | etc.
            index: 17
            extensions: {}
            elements:
              extension: {index: 18}
              url:
                pattern: {type: Uri, value: language}
                index: 19
              value:
                choices: [valueCode]
                index: 21
              valueCode: {type: code, choiceOf: value, index: 22}
            required: [valueCode, value]
        expression:
          match: {url: expression}
          schema:
            short: Expression in specified language
            index: 23
            extensions: {}
            elements:
              extension: {index: 24}
              url:
                pattern: {type: Uri, value: expression}
                index: 25
              value:
                choices: [valueString]
                index: 27
              valueString: {type: string, choiceOf: value, index: 28}
            required: [valueString, value]
        reference:
          match: {url: reference}
          schema:
            short: Where the expression is found
            index: 29
            extensions: {}
            elements:
              extension: {index: 30}
              url:
                pattern: {type: Uri, value: reference}
                index: 31
              value:
                choices: [valueUri]
                index: 33
              valueUri: {type: uri, choiceOf: value, index: 34}
            required: [valueUri, value]
  url:
    pattern: {type: Uri, value: 'http://hl7.org/fhir/StructureDefinition/valueset-expression'}
    index: 35
  value:
    choices: []
    index: 37
package_version: 5.3.0-ballot-tc1
extensions:
  _datatype:
    url: h
    type: Extension
    short: DataType name 'Expression' from R5
    index: 1
    elements:
      value:
        pattern: {type: String, value: Expression}
        choices: [valueString]
        index: 3
      valueString:
        type: string
        pattern: {type: String, value: Expression}
        choiceOf: value
        index: 4
    required: [valueString, value]
  description:
    url: description
    short: Natural language description of the condition
    index: 5
    extensions: {}
    elements:
      extension: {index: 6}
      url:
        pattern: {type: Uri, value: description}
        index: 7
      value:
        choices: [valueString]
        index: 9
      valueString: {type: string, choiceOf: value, index: 10}
    required: [valueString, value]
  name:
    url: name
    short: Short name assigned to expression for reuse
    index: 11
    extensions: {}
    elements:
      extension: {index: 12}
      url:
        pattern: {type: Uri, value: name}
        index: 13
      value:
        choices: [valueCode]
        index: 15
      valueCode: {type: code, choiceOf: value, index: 16}
    required: [valueCode, value]
  language:
    url: language
    short: text/cql | text/fhirpath | application/x-fhir-query | etc.
    index: 17
    extensions: {}
    elements:
      extension: {index: 18}
      url:
        pattern: {type: Uri, value: language}
        index: 19
      value:
        choices: [valueCode]
        index: 21
      valueCode: {type: code, choiceOf: value, index: 22}
    required: [valueCode, value]
  expression:
    url: expression
    short: Expression in specified language
    index: 23
    extensions: {}
    elements:
      extension: {index: 24}
      url:
        pattern: {type: Uri, value: expression}
        index: 25
      value:
        choices: [valueString]
        index: 27
      valueString: {type: string, choiceOf: value, index: 28}
    required: [valueString, value]
  reference:
    url: reference
    short: Where the expression is found
    index: 29
    extensions: {}
    elements:
      extension: {index: 30}
      url:
        pattern: {type: Uri, value: reference}
        index: 31
      value:
        choices: [valueUri]
        index: 33
      valueUri: {type: uri, choiceOf: value, index: 34}
    required: [valueUri, value]
class: extension
kind: complex-type
url: http://hl7.org/fhir/StructureDefinition/valueset-expression
base: http://hl7.org/fhir/StructureDefinition/Extension
version: 5.3.0-ballot-tc1