Stream: questionnaire
Topic: Can valueExpression be missing from calculatedExpression?
Paul Lynch (Dec 11 2018 at 19:17):
I might be misunderstanding the intent of the cardinality indicators in http://hl7.org/fhir/2018Sep/extension-questionnaire-calculatedexpression.html, but it looks like, within the calculatedExpression extension, the "valueExpression" property has as a cardinality of 0..1. Do we really want to allow it to be missing?
Grahame Grieve (Dec 11 2018 at 21:56):
there are valid uses generally for expression to be missing
Lloyd McKenzie (Dec 11 2018 at 22:14):
There's valid reasons for the extension to be missing. But if the extension is present the value should have to be present (given that extensions are prohibited)
Lloyd McKenzie (Dec 11 2018 at 22:14):
In practice, the requirement that the extension has to have a child will force the valueExpression to be present regardless, but we may as well make that explicit.
Paul Lynch (Dec 13 2018 at 17:35):
Grahame Grieve (Dec 13 2018 at 19:55):
yes it can be missing, but it's not very useful, particularly in the context of a questionnaire
Paul Lynch (Dec 13 2018 at 21:28):
This extension is specific to Questionnaire (the full name being "questionnaire-calculatedExpression"), so if it is not useful for it to be missing in that context, why allow it?
Grahame Grieve (Dec 13 2018 at 21:30):
I am ok with Expression.expression being required on the extension, yes
Lloyd McKenzie (Dec 13 2018 at 23:08):
The value can't be missing. Extension only allows id, extension and value. And in this case, extension is prohibited. The rules require that an element have a descendant other than id, so value has no choice but to be present if the extension is present.
Grahame Grieve (Dec 13 2018 at 23:54):
that's not the question. Paul is asking about valueExpression.expression
Paul Lynch (Dec 14 2018 at 16:29):
Actually, no. I was asking about valueExpression being missing from the questionnaire-calculatedExpression extension. I was looking at the page http://hl7.org/fhir/2018Sep/extension-questionnaire-calculatedexpression.html, on the "Full Structure" tab, which shows 0..1 for valueExpression.
Last updated: Apr 12 2022 at 19:14 UTC
