title: Fabric Composer o vs -->
body: <p>I can't find any docs on this, so what is the difference between <code>o</code> and <code>--&gt;</code> in <a href="https://fabric-composer.github.io/index.html" rel="nofollow noreferrer">Fabric Composer</a>, and under what circumstances should they be used?</p>
  
  <p>Consider this...</p>
  
  <pre><code>asset Document identified by docId {
      o String docId
      o Articles[] articles
  }
  </code></pre>
  
  <p>vs this...</p>
  
  <pre><code>asset Document identified by docId {
      o String docId
      --&gt; Articles[] articles
  }
  </code></pre>