Callimachus can only loop over properties and relationships present in the RDF store.

Any element with the @property attribute will be repeated (or not shown at all) for every matching property value in the RDF store.

<body resource="?this">
  <h2>List of values for the current resource</h2>
  <ul>
    <li property="rdf:value" content="?value">
      <!-- this li element may be repeated -->
    </li>
  </ul>
</body>

Any element with @rel or @rev attribute and a @resource attribute will be repeated (or not shown at all) for every matching relationship partner in the RDF store.

<body resource="?this">
  <h2>List of friends for the current resource</h2>
  <ul>
    <li rel="foaf:knows" resource="?friend">
      <!-- this li element may be repeated -->
    </li>
  </ul>
</body>