Structured Data Capture
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Structured Data Capture, published by HL7 International / FHIR Infrastructure. This guide is not an authorized publication; it is the continuous build for version 4.0.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/sdc/ and changes regularly. See the Directory of published versions

Extension: EnableWhenExpressionExtension - Detailed Descriptions

Page standards status: Trial-use Maturity Level: 4

Definitions for the sdc-questionnaire-enableWhenExpression extension.

Guidance on how to interpret the contents of this table can be found here

0. Extension
Definition

An expression that returns a boolean value for whether to enable the item.

ShortExpression for when to enable the item
Comments

This is only permitted when the containing item does NOT have any enableWhen elements.

If the expression involves comparisons between elements that have different precisions but are otherwise equal, FHIRPath will resolve the expression to an empty set, which will in turn evaluate to false (meaning the item won't be enabled). If this is not the desired behavior, the author should add a .allTrue() to the end of the expression, which will result in an indeterminate outcome because of precision differences being handled as 'true' and the item being enabled. Questionnaires SHOULD be designed to take into account challenges around varying precision to minimize non-deterministic situations by setting constraints around expected precision, etc.

If the expression evaluates to something other than a boolean true or false, the Form Filler SHOULD still display the form, and if it does so, SHOULD treat the element as 'enabled' and display a warning to the user that the questionnaire logic was faulty and it's possible that the item shouldn't be enabled.

Control0..1
2. Extension.extension
Control0..0
4. Extension.url
Fixed Valuehttp://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-enableWhenExpression
6. Extension.value[x]
TypeExpression, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, Coding, SampledData, id, positiveInt, Distance, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, CodeableConcept, ParameterDefinition, dateTime, code, string, Contributor, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Signature, unsignedInt, time
[x] NoteSeeChoice of Data Typesfor further information about how to use [x]
Invariantssdc-inv1: FHIR query language not allowed. (language!='application/x-fhir-query')

Guidance on how to interpret the contents of this table can be found here

0. Extension
Definition

An expression that returns a boolean value for whether to enable the item.


Optional Extension Element - found in all resources.

ShortExpression for when to enable the itemOptional Extensions Element
Comments

This is only permitted when the containing item does NOT have any enableWhen elements.

If the expression involves comparisons between elements that have different precisions but are otherwise equal, FHIRPath will resolve the expression to an empty set, which will in turn evaluate to false (meaning the item won't be enabled). If this is not the desired behavior, the author should add a .allTrue() to the end of the expression, which will result in an indeterminate outcome because of precision differences being handled as 'true' and the item being enabled. Questionnaires SHOULD be designed to take into account challenges around varying precision to minimize non-deterministic situations by setting constraints around expected precision, etc.

If the expression evaluates to something other than a boolean true or false, the Form Filler SHOULD still display the form, and if it does so, SHOULD treat the element as 'enabled' and display a warning to the user that the questionnaire logic was faulty and it's possible that the item shouldn't be enabled.

Control0..1*
This element is affected by the following invariants: ele-1
Is Modifierfalse
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
2. Extension.extension
Definition

An Extension


May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortExtensionAdditional content defined by implementations
Comments

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Control0..0*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
SlicingThis element introduces a set of slices on Extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
    • 4. Extension.url
    Definition

    Source of the definition for the extension code - a logical name or a URL.

    Shortidentifies the meaning of the extension
    Comments

    The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

    Control1..1
    Typeuri
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    Fixed Valuehttp://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-enableWhenExpression
    6. Extension.value[x]
    Definition

    Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

    ShortValue of extension
    Control0..1
    TypeExpression, date, Meta, Address, Attachment, integer, Count, DataRequirement, Dosage, uuid, Identifier, Coding, SampledData, id, positiveInt, Distance, Period, Duration, canonical, Range, RelatedArtifact, base64Binary, UsageContext, Timing, decimal, CodeableConcept, ParameterDefinition, dateTime, code, string, Contributor, oid, instant, ContactPoint, HumanName, Money, markdown, Ratio, Age, Reference, TriggerDefinition, Quantity, uri, url, Annotation, ContactDetail, boolean, Signature, unsignedInt, time
    [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
    Is Modifierfalse
    Summaryfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    sdc-inv1: FHIR query language not allowed. (language!='application/x-fhir-query')

    Guidance on how to interpret the contents of this table can be found here

    0. Extension
    Definition

    An expression that returns a boolean value for whether to enable the item.

    ShortExpression for when to enable the item
    Comments

    This is only permitted when the containing item does NOT have any enableWhen elements.

    If the expression involves comparisons between elements that have different precisions but are otherwise equal, FHIRPath will resolve the expression to an empty set, which will in turn evaluate to false (meaning the item won't be enabled). If this is not the desired behavior, the author should add a .allTrue() to the end of the expression, which will result in an indeterminate outcome because of precision differences being handled as 'true' and the item being enabled. Questionnaires SHOULD be designed to take into account challenges around varying precision to minimize non-deterministic situations by setting constraints around expected precision, etc.

    If the expression evaluates to something other than a boolean true or false, the Form Filler SHOULD still display the form, and if it does so, SHOULD treat the element as 'enabled' and display a warning to the user that the questionnaire logic was faulty and it's possible that the item shouldn't be enabled.

    Control0..1
    This element is affected by the following invariants: ele-1
    Is Modifierfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    2. Extension.id
    Definition

    Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

    ShortUnique id for inter-element referencing
    Control0..1
    Typestring
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    4. Extension.extension
    Definition

    An Extension

    ShortExtension
    Control0..0
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    SlicingThis element introduces a set of slices on Extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
      • 6. Extension.url
      Definition

      Source of the definition for the extension code - a logical name or a URL.

      Shortidentifies the meaning of the extension
      Comments

      The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

      Control1..1
      Typeuri
      Is Modifierfalse
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      Fixed Valuehttp://hl7.org/fhir/uv/sdc/StructureDefinition/sdc-questionnaire-enableWhenExpression
      8. Extension.value[x]
      Definition

      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

      ShortValue of extension
      Control0..1
      TypeExpression
      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      sdc-inv1: FHIR query language not allowed. (language!='application/x-fhir-query')