FHIR Chat · Defining nested inline extensions

Stream: shorthand

Topic: Defining nested inline extensions

Jean Duteau (Nov 18 2020 at 19:59):

I thought I had done this before but I can't find any examples in my IGuides. I want to create a complex inline extension where one of the extension slices has extensions:

Extension: ItemRule
Id: extension-itemRule
Description: "Provides a set of rules that provide logic on which questions should be navigated to"
* extension contains ruleType 1..1 MS and rules 1..* MS and skipTo 1..1 MS
* extension[ruleType].value[x] only code
* extension[ruleType].valueCode from ItemRuleType (required)
* extension[skipTo].value[x] only string
* extension[rules] contains operator 1..1 MS and value 1..1 MS and fact 1..1 MS
* extension[rules][operator].value[x] only code
* extension[rules][operator].valueCode from ItemRuleOperatorType (required)
* extension[rules][operator].value[x] only string
* extension[rules][fact].value[x] only string

When I do this, I get an error about not being to create the operator slice:

error Cannot create operator slice. No slicing found for Extension.extension:rules.
  File: /Users/jeanduteau/Documents/DDIWork/IBM-BEST/datastandards/questionnaire-fsh/Questionnaire.fsh
  Line: 179

Help me Obi-Wan Kenobi, you're my only hope!

Chris Moesel (Nov 18 2020 at 20:58):

This is confusing for sure, but I think that extension[rules] contains... actually re-slices the rules slice -- because extension[rules] is still referring to the rules extension itself.

I think what you really want is extension[rules].extension contains... and then refer to the sub-extensions by extension[rules].extension[operator], etc.

Chris Moesel (Nov 18 2020 at 21:04):

I just tested this in FSH Online and it worked:

Extension: ItemRule
Id: extension-itemRule
Description: "Provides a set of rules that provide logic on which questions should be navigated to"
* extension contains ruleType 1..1 MS and rules 1..* MS and skipTo 1..1 MS
* extension[ruleType].value[x] only code
* extension[ruleType].valueCode from ItemRuleType (required)
* extension[skipTo].value[x] only string
* extension[rules].extension contains operator 1..1 MS and value 1..1 MS and fact 1..1 MS
* extension[rules].extension[operator].value[x] only code
* extension[rules].extension[operator].valueCode from ItemRuleOperatorType (required)
* extension[rules].extension[fact].value[x] only string

ValueSet: ItemRuleType

ValueSet: ItemRuleOperatorType

Note that in your original FSH you tried to constrain the operator to a code and a string, so I removed the 2nd constraint.

Jean Duteau (Nov 18 2020 at 21:31):

thanks. that makes way more sense

Last updated: Apr 12 2022 at 19:14 UTC