Release 4 4B

This page is part of the FHIR Specification (v4.0.1: R4 (v4.3.0: R4B - Mixed Normative and STU ) in it's permanent home (it will always be available at this URL). ). The current version which supercedes this version is 5.0.0 . For a full list of available versions, see the Directory of published versions . Page versions: R4B R4 R4B R4

Extension: Variable

FHIR Infrastructure Work Group   Maturity Level : 1 Informative Use Context : Any

URL for this extension: 


http://hl7.org/fhir/StructureDefinition/variable

Status: draft. Extension maintained by: Health Level Seven International (FHIR Infrastructure)

Variable specifying a logic to generate a variable for use in subsequent logic. The name of the variable will be added to FHIRPath's context when processing descendants of the element that contains this extension.

Comment :

Ordering of variable extension declarations is significant as variables declared in one repetition of this extension might be used in subsequent extension repetitions.

Context of Use: Use on Element ID Questionnaire, Element ID Questionnaire.item or Element ID Questionnaire.item.item

Extension Content

Summary

Name Flags Card. Type Description & Constraints doco
. . Variable 0..* Expression URL = http://hl7.org/fhir/StructureDefinition/variable
Variable: Variable specifying a logic to generate a variable for use in subsequent logic. The name of the variable will be added to FHIRPath's context when processing descendants of the element that contains this extension.


Use on Element ID Questionnaire, Element ID Questionnaire.item or Element ID Questionnaire.item.item

doco Documentation for this format

Full Structure

Name Flags Card. Type Description & Constraints doco
. . extension 0..* Extension URL = http://hl7.org/fhir/StructureDefinition/variable
Variable: Variable specifying a logic to generate a variable for use in subsequent logic. The name of the variable will be added to FHIRPath's context when processing descendants of the element that contains this extension.


Use on Element ID Questionnaire, Element ID Questionnaire.item or Element ID Questionnaire.item.item
. . . extension I 0..0
. . . url 1..1 uri "http://hl7.org/fhir/StructureDefinition/variable"
. . . value[x] I 1..1 Expression Value of extension

doco Documentation for this format

XML Template 

<!-- Variable -->doco

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/variable" >
  <!-- from Element: extension -->
 <</valueExpression>

 <valueExpression><!-- ?? 1..1 Expression Value of extension --></valueExpression>

</extension>

JSON Template 

{ // Variable
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/variable", // R! 
    "

    "valueExpression" : { Expression } // C? R! Value of extension

  }

Summary

Name Flags Card. Type Description & Constraints doco
. . Variable 0..* Expression URL = http://hl7.org/fhir/StructureDefinition/variable
Variable: Variable specifying a logic to generate a variable for use in subsequent logic. The name of the variable will be added to FHIRPath's context when processing descendants of the element that contains this extension.


Use on Element ID Questionnaire, Element ID Questionnaire.item or Element ID Questionnaire.item.item

doco Documentation for this format

Full Structure

Name Flags Card. Type Description & Constraints doco
. . extension 0..* Extension URL = http://hl7.org/fhir/StructureDefinition/variable
Variable: Variable specifying a logic to generate a variable for use in subsequent logic. The name of the variable will be added to FHIRPath's context when processing descendants of the element that contains this extension.


Use on Element ID Questionnaire, Element ID Questionnaire.item or Element ID Questionnaire.item.item
. . . extension I 0..0
. . . url 1..1 uri "http://hl7.org/fhir/StructureDefinition/variable"
. . . value[x] I 1..1 Expression Value of extension

doco Documentation for this format

XML Template 

<!-- Variable -->doco

<extension xmlns="http://hl7.org/fhir"
     url="http://hl7.org/fhir/StructureDefinition/variable" >
  <!-- from Element: extension -->
 <</valueExpression>

 <valueExpression><!-- ?? 1..1 Expression Value of extension --></valueExpression>

</extension>

JSON Template 

{ // Variable
  // from Element: extension
    "extension" : [ //  sliced by value:url  in the specified order, Open ]
    "url" : "http://hl7.org/fhir/StructureDefinition/variable", // R! 
    "

    "valueExpression" : { Expression } // C? R! Value of extension

  }

 

Constraints

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