The rule is implemented in Schematron as defined by the Schematron standard [ISOSCHEMA]. In addition, the @see attribute is used for linking the Schematron rule back to the documented constraint.

<sch:rule context="cabin-bag/weight">
    <sch:let 
      name="bag-weight" 
      value="xs:float(.)"/>
    <sch:let 
      name="passenger-name" 
      value="../../name"/>
    <sch:assert 
      test="$bag-weight le 8" 
      see="http://www.cabin-bag.info/c1"
      diagnostics="diag-weight-8">
        The weight of cabin luggage is 8kg 
        or less.
    </sch:assert>
</sch:rule>

More context information is given by using Schematron’s diagnostic element.

<sch:diagnostic id="diag-weight-8">
  The cabin luggage of 
  <sch:value-of select="$passenger-name"/>
  exceeded the maximum weight allowance by 
  <sch:value-of select="$bag-weight -8"/>kg.
  Pack lighter!
</sch:diagnostic>