Current Build

Extension: expression

Vocabulary Work Group Maturity Level: 1InformativeUse Context: Any

URL for this extension:

http://hl7.org/fhir/StructureDefinition/valueset-expression

Status: draft. Extension maintained by: HL7

An expression that provides an alternative definition of the content of the value set. There are two different ways to use this expression extension: If both an expression and a compose element is present, the compose is understood the make the same statement as the expression. If there is no compose, the expression is the only definition of the value set, and the value set can only be processed by a server that understands the expression syntax, it that is computable.

Comment:

The expression may be a reference or the actual expression, and ss expected to be a computable format (use the rules-text extension for a non-computable description).

Context of Use: Use on Element ID ValueSet

Extension Content

Summary

NameFlagsCard.TypeDescription & Constraintsdoco
.. expression0..1ExpressionURL = http://hl7.org/fhir/StructureDefinition/valueset-expression
expression: An expression that provides an alternative definition of the content of the value set. There are two different ways to use this expression extension: If both an expression and a compose element is present, the compose is understood the make the same statement as the expression. If there is no compose, the expression is the only definition of the value set, and the value set can only be processed by a server that understands the expression syntax, it that is computable.


Use on Element ID ValueSet

doco Documentation for this format

Full Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. extension0..1ExtensionURL = http://hl7.org/fhir/StructureDefinition/valueset-expression
expression: An expression that provides an alternative definition of the content of the value set. There are two different ways to use this expression extension: If both an expression and a compose element is present, the compose is understood the make the same statement as the expression. If there is no compose, the expression is the only definition of the value set, and the value set can only be processed by a server that understands the expression syntax, it that is computable.


Use on Element ID ValueSet
... extension 0..0
... url 1..1uri"http://hl7.org/fhir/StructureDefinition/valueset-expression"
... valueExpression 0..1ExpressionValue of extension

doco Documentation for this format

XML Template

<!-- expression -->doco

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/valueset-expression" >
  <!-- from Element: extension -->
 <valueExpression><!-- 0..1 Expression Value of extension --></valueExpression>
</extension>

JSON Template

{ // expression
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/valueset-expression", // R! 
    "valueExpression" : { Expression } //Value of extension
  }

Summary

NameFlagsCard.TypeDescription & Constraintsdoco
.. expression0..1ExpressionURL = http://hl7.org/fhir/StructureDefinition/valueset-expression
expression: An expression that provides an alternative definition of the content of the value set. There are two different ways to use this expression extension: If both an expression and a compose element is present, the compose is understood the make the same statement as the expression. If there is no compose, the expression is the only definition of the value set, and the value set can only be processed by a server that understands the expression syntax, it that is computable.


Use on Element ID ValueSet

doco Documentation for this format

Full Structure

NameFlagsCard.TypeDescription & Constraintsdoco
.. extension0..1ExtensionURL = http://hl7.org/fhir/StructureDefinition/valueset-expression
expression: An expression that provides an alternative definition of the content of the value set. There are two different ways to use this expression extension: If both an expression and a compose element is present, the compose is understood the make the same statement as the expression. If there is no compose, the expression is the only definition of the value set, and the value set can only be processed by a server that understands the expression syntax, it that is computable.


Use on Element ID ValueSet
... extension 0..0
... url 1..1uri"http://hl7.org/fhir/StructureDefinition/valueset-expression"
... valueExpression 0..1ExpressionValue of extension

doco Documentation for this format

XML Template

<!-- expression -->doco

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/valueset-expression" >
  <!-- from Element: extension -->
 <valueExpression><!-- 0..1 Expression Value of extension --></valueExpression>
</extension>

JSON Template

{ // expression
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/valueset-expression", // R! 
    "valueExpression" : { Expression } //Value of extension
  }

 

Constraints

  • ele-1: All FHIR elements must have a @value or children (xpath: @value|f:*|h:div)
  • ext-1: Must have either extensions or value[x], not both (xpath: exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')]))