FHIR Chat · Forge and extensions

Have updated to the latest Forge but a little bit confused about the way extensions are represented. Is there any particular reason that "id" is now shown when creating an extension? And any reason that "url" is not shown? Seems to be a change from the previous version.

Jonny Rylands (Mar 14 2016 at 12:08):

Ah - to answer my own (first) question! - just noticed the message from Michael Rutten in conformance about Element.id being expanded. Though not sure why url is NOT visible.

Michel Rutten (Mar 14 2016 at 12:19):

Hi Jonny,

in Forge, the extension.url child element is hidden and generated automatically, with a value that is fixed to the complex extension element name. You can confirm this by inspecting the serialized Xml output. As the FHIR specification explicitly defines the rules for this element value, we can generate it automatically so the user doesn't have to. And there is no practical need for a user to change to manually constrain the url element. Therefore we decided to hide this element and provide a simplified view on the extension definition structure; url nodes would only clutter the UI.

The latest release also expands the Element.Id node. In an upcoming minor update, this behavior will be configurable and disabled by default. You can then toggle this behavior via the configuration setting "Expand common elements" in the Options menu.

Jonny Rylands (Mar 14 2016 at 12:23):

OK great.

Jonny Rylands (Mar 14 2016 at 12:30):

Just thinking through this, it makes sense for simple extensions, and for the "root" of complex extensions. But how do you specify the fixedValue for the URLs of the sub elements of complex extensions?

Michel Rutten (Mar 14 2016 at 12:51):

Hi Jonny, according to the FHIR specification, the url of a complex extension element definition must be fixed to the extension element name. See e.g. this official complex extension definition:
http://hl7-fhir.github.io/extension-goal-target.xml.html

<element>
    <path value="Extension.extension"/>
    <name value="measure"/>
</element>
<element>
    <path value="Extension.extension.url"/>
    <fixedUri value="measure"/>
</element>
<element>
    <path value="Extension.extension.valueCodeableConcept"/>
    <type>
        <code value="CodeableConcept"/>
    </type>
</element>

Jonny Rylands (Mar 14 2016 at 12:55):

Ah OK...makes more sense now, thanks!

Last updated: Apr 12 2022 at 19:14 UTC

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FHIR Chat · Forge and extensions · implementers

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