  (<span class="mdzsyn-coresym">def</span> <span class="mdzsyn-symbol">c</span> <span class="mdzsyn-number">3</span>)
  (<span class="mdzsyn-coresym">+</span> <span class="mdzsyn-symbol">a</span> <span class="mdzsyn-symbol">b</span> <span class="mdzsyn-symbol">c</span>)) <span class="mdzsyn-comment"># -&gt; 6</span>

<span class="mdzsyn-symbol">a</span> <span class="mdzsyn-comment"># -&gt; :outera</span>
<span class="mdzsyn-symbol">b</span> <span class="mdzsyn-comment"># -&gt; compile error: "unknown symbol