<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="codesystem-alternate" />
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="vocab" />
  </extension>
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="1" />
  </extension>
  <url value="http://hl7.org/fhir/StructureDefinition/codesystem-alternate" />
  <version value="4.0.0" />
  <name value="alternate" />
  <status value="draft" />
  <date value="2018-12-27T22:37:54+11:00" />
  <publisher value="HL7" />
  <description value="An additional code that may be used to represent the concept." />
  <fhirVersion value="4.0.0" />
  <mapping>
    <identity value="rim" />
    <uri value="http://hl7.org/v3" />
    <name value="RIM Mapping" />
  </mapping>
  <kind value="complex-type" />
  <abstract value="false" />
  <context>
    <type value="element" />
    <expression value="CodeSystem.concept" />
  </context>
  <type value="Extension" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Extension" />
  <derivation value="constraint" />
  <differential>
    <element id="Extension">
      <path value="Extension" />
      <short value="Additional code for the concept" />
      <definition value="An additional code that may be used to represent the concept." />
      <comment value="Few coding systems define synonyms. A few more define alternate codes for special case use." />
      <min value="0" />
      <max value="*" />
      <isModifier value="false" />
    </element>
    <element id="Extension.extension:code">
      <path value="Extension.extension" />
      <sliceName value="code" />
      <short value="Code that represents the concept" />
      <definition value="The code that may be used to represent the concept." />
      <min value="1" />
      <max value="1" />
      <type>
        <code value="Extension" />
      </type>
    </element>
    <element id="Extension.extension:code.extension">
      <path value="Extension.extension.extension" />
      <max value="0" />
    </element>
    <element id="Extension.extension:code.url">
      <path value="Extension.extension.url" />
      <type>
        <code value="uri" />
      </type>
      <fixedUri value="code" />
    </element>
    <element id="Extension.extension:code.valueCode">
      <path value="Extension.extension.valueCode" />
      <type>
        <code value="code" />
      </type>
    </element>
    <element id="Extension.extension:use">
      <path value="Extension.extension" />
      <sliceName value="use" />
      <short value="Expected use of the code" />
      <definition value="Defines why this additional code is defined." />
      <comment value="Further work is needed on the value set." />
      <min value="1" />
      <max value="1" />
      <type>
        <code value="Extension" />
      </type>
    </element>
    <element id="Extension.extension:use.extension">
      <path value="Extension.extension.extension" />
      <max value="0" />
    </element>
    <element id="Extension.extension:use.url">
      <path value="Extension.extension.url" />
      <type>
        <code value="uri" />
      </type>
      <fixedUri value="use" />
    </element>
    <element id="Extension.extension:use.valueCoding">
      <path value="Extension.extension.valueCoding" />
      <type>
        <code value="Coding" />
      </type>
      <binding>
        <extension url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="AlternativeCodeKind" />
        </extension>
        <strength value="extensible" />
        <description value="Indicates the type of use for which the code is defined." />
        <valueSet value="http://hl7.org/fhir/ValueSet/codesystem-altcode-kind" />
      </binding>
    </element>
    <element id="Extension.url">
      <path value="Extension.url" />
      <type>
        <code value="uri" />
      </type>
      <fixedUri value="http://hl7.org/fhir/StructureDefinition/codesystem-alternate" />
    </element>
    <element id="Extension.value[x]">
      <path value="Extension.value[x]" />
      <min value="0" />
      <max value="0" />
    </element>
  </differential>
</StructureDefinition>