StructureDefinition for code

<?xml version="1.0" encoding="UTF-8"?>

<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="code"/> 
  <text> 
    <status value="generated"/> 
    <div xmlns="http://www.w3.org/1999/xhtml">to do</div> 
  </text> 
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="normative"/> 
  </extension> 
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-normative-version">
    <valueCode value="4.0.0"/> 
  </extension> 
  <url value="http://hl7.org/fhir/StructureDefinition/code"/> 
  <version value="5.0.0-ballot"/> 
  <name value="code"/> 
  <status value="active"/> 
  <experimental value="false"/> 
  <date value="2022-09-07T10:58:29+10:00"/> 
  <publisher value="HL7 FHIR Standard"/> 
  <contact> 
    <telecom> 
      <system value="url"/> 
      <value value="http://hl7.org/fhir"/> 
    </telecom> 
  </contact> 
  <description value="code type: A string which has at least one character and no leading or trailing whitespace
   and where there is no whitespace other than single spaces in the contents"/> 
  <fhirVersion value="5.0.0-ballot"/> 
  <kind value="primitive-type"/> 
  <abstract value="false"/> 
  <type value="code"/> 
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/string"/> 
  <derivation value="specialization"/> 
  <snapshot> 
    <element id="code">
      <path value="code"/> 
      <short value="Primitive Type code"/> 
      <definition value="A string which has at least one character and no leading or trailing whitespace and where
       there is no whitespace other than single spaces in the contents"/> 
      <min value="0"/> 
      <max value="*"/> 
      <base> 
        <path value="code"/> 
        <min value="0"/> 
        <max value="*"/> 
      </base> 
      <constraint> 
        <key value="ele-1"/> 
        <severity value="error"/> 
        <human value="All FHIR elements must have a @value or children"/> 
        <expression value="hasValue() or (children().count() &gt; id.count())"/> 
        <xpath value="@value|f:*|h:div"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      <isModifier value="false"/> 
      <isSummary value="false"/> 
    </element> 
    <element id="code.id">
      <path value="code.id"/> 
      <representation value="xmlAttr"/> 
      <short value="xml:id (or equivalent in JSON)"/> 
      <definition value="unique id for the element within a resource (for internal references)"/> 
      <min value="0"/> 
      <max value="1"/> 
      <base> 
        <path value="Element.id"/> 
        <min value="0"/> 
        <max value="1"/> 
      </base> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler magic
       (h)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="string"/> 
        </extension> 
        <code value="http://hl7.org/fhirpath/System.String"/> 
      </type> 
      <isModifier value="false"/> 
      <isSummary value="false"/> 
    </element> 
    <element id="code.extension">
      <path value="code.extension"/> 
      <short value="Additional content defined by implementations"/> 
      <definition value="May be used to represent additional information that is not part of the basic definition
       of the resource. 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."/> 
      <comment value="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."/> 
      <alias value="extensions"/> 
      <alias value="user content"/> 
      <min value="0"/> 
      <max value="*"/> 
      <base> 
        <path value="Element.extension"/> 
        <min value="0"/> 
        <max value="*"/> 
      </base> 
      <type> 
        <code value="Extension"/> 
      </type> 
      <constraint> 
        <key value="ele-1"/> 
        <severity value="error"/> 
        <human value="All FHIR elements must have a @value or children"/> 
        <expression value="hasValue() or (children().count() &gt; id.count())"/> 
        <xpath value="@value|f:*|h:div"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      <constraint> 
        <key value="ext-1"/> 
        <severity value="error"/> 
        <human value="Must have either extensions or value[x], not both"/> 
        <expression value="extension.exists() != value.exists()"/> 
        <xpath value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/> 
      </constraint> 
      <isModifier value="false"/> 
      <isSummary value="false"/> 
    </element> 
    <element id="code.value">
      <path value="code.value"/> 
      <representation value="xmlAttr"/> 
      <short value="Primitive value for code"/> 
      <definition value="Primitive value for code"/> 
      <min value="0"/> 
      <max value="1"/> 
      <base> 
        <path value="string.value"/> 
        <min value="0"/> 
        <max value="1"/> 
      </base> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler magic
       (i)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="code"/> 
        </extension> 
        <extension url="http://hl7.org/fhir/StructureDefinition/regex">
          <valueString value="[^\s]+( [^\s]+)*"/> 
        </extension> 
        <code value="http://hl7.org/fhirpath/System.String"/> 
      </type> 
      <isModifier value="false"/> 
      <isSummary value="false"/> 
    </element> 
  </snapshot> 
  <differential> 
    <element id="code">
      <path value="code"/> 
      <short value="Primitive Type code"/> 
      <definition value="A string which has at least one character and no leading or trailing whitespace and where
       there is no whitespace other than single spaces in the contents"/> 
      <min value="0"/> 
      <max value="*"/> 
    </element> 
    <element id="code.value">
      <path value="code.value"/> 
      <representation value="xmlAttr"/> 
      <short value="Primitive value for code"/> 
      <definition value="Primitive value for code"/> 
      <min value="0"/> 
      <max value="1"/> 
    <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler magic
       (g)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="code"/> 
        </extension> 
        <extension url="http://hl7.org/fhir/StructureDefinition/regex">
          <valueString value="[^\s]+( [^\s]+)*"/> 
        </extension> 
        <code value="http://hl7.org/fhirpath/System.String"/> 
      </type> 
    </element> 
  </differential> 
</StructureDefinition>