Stream: IG creation
Topic: slicing on meta.profile
Brian Reinhold (Feb 23 2019 at 09:17):
I was once told that I did not have to do slicing on a meta.profile but that may have been a misunderstanding. I want to require that implementations following a phd profile enter at least one URL in the meta.profile element which is a fixed value. However, other meta.profile URLs are also allowed if the resource is also compliant to those profiles. But I am not sure how to do that. When I don't slice I get something that looks like I have 1..* profile elements of a fixed value. At least one could interpret it that way.
So I tried this
<element id="Device.meta.profile">
<path value="Device.meta.profile" />
<slicing>
<discriminator>
<type value="value" />
<path value="$this" />
</discriminator>
<rules value="open" />
</slicing>
<min value="1" />
</element>
<element id="Device.meta.profile:phdProfile">
<path value="Device.meta.profile" />
<sliceName value="phdProfile" />
<min value="1" />
<max value="1" />
<fixedUri value="http://hl7.org/fhir/uv/phd/StructureDefinition/PhdDevice" />
</element>
But when doing that Lloyd's framework build gives me an error saying it can't resolve the discriminator. The Example is exactly as it should be
"meta": {
"profile": [
"http://hl7.org/fhir/uv/phd/StructureDefinition/PhdDevice"
]
},
and the built structure definition looks exactly as I want it to look; the generic profile is a sum, and the sliced profile is one fixed value. It makes more sense than the previous no-slice (but no error) but having 1..* on the fixed value.
Lloyd McKenzie (Feb 23 2019 at 15:33):
If you want to set expectations on one repetition while allowing arbitrary other repetitions, the only way to accomplish that is with slicing.
Brian Reinhold (Feb 23 2019 at 15:35):
If you want to set expectations on one repetition while allowing arbitrary other repetitions, the only way to accomplish that is with slicing.
@Lloyd McKenzie
okay, that's what I did above but the validator gives a cant resolve discriminator error. Any idea why?
Is it the path?
Lloyd McKenzie (Feb 23 2019 at 15:41):
Try path = value
Brian Reinhold (Feb 23 2019 at 15:43):
@Lloyd McKenzie
shorthand for <path value="value" />?
Lloyd McKenzie (Feb 23 2019 at 15:51):
y
Brian Reinhold (Feb 23 2019 at 17:39):
(deleted)
Rob Hausam (Feb 25 2019 at 06:50):
So that is actually valid syntax for the path? If so, I've missed it in the ElementDefinition and restricted FHIRPath documentation. As far as I know, the only place to use 'value' is in discriminator.type, not discriminator.path.
Brian Reinhold (Feb 25 2019 at 10:44):
So that is actually valid syntax for the path? If so, I've missed it in the ElementDefinition and restricted FHIRPath documentation. As far as I know, the only place to use 'value' is in discriminator.type, not discriminator.path.
Rob,
I am also looking for the documentation on that. I know that I was stuck on that slicing for a long time; so simple: I have a list of URLs but I have to define slicing 'outside' of the list. There was no element in meta.profile to make a path to. I am still trying to find something in the slicing documentation or the FHIRPath material it references that indicates that I should have used <path value="value" /> and what that means.
In general I think the slicing docs need to be increased. Would like to see examples of each case. 'pattern' and those functions, for example. I still don't really understand how they work and what they can do.
Rob Hausam (Feb 25 2019 at 17:18):
So have you been able to try <path value="value" /> and have found that it works (not just doesn't generate errors)? If so, that would definitely be good to know.
Brian Reinhold (Feb 25 2019 at 17:20):
So have you been able to try <path value="value" /> and have found that it works (not just doesn't generate errors)? If so, that would definitely be good to know.
Works like a charm!!
I think that needs to be documented. I really could not find out how to slice on a simple list of primitives
Lloyd McKenzie (Feb 25 2019 at 17:20):
Submit a change request
Rob Hausam (Feb 25 2019 at 17:33):
Yes, we need to document that. Broadening the question again, I assume that we still can't effectively slice on type = "profile" (which is what we originally wanted to do)? Our use case was slicing on Composition.section.entry(), as described in the documentation for the discriminator type 'profile'.
Last updated: Apr 12 2022 at 19:14 UTC
