span class="p">((</span><span class="nv">ago = </span><span class="nx">@tag</span> <span class="nx">i</span> <span class="o">-</span> <span class="mi">2</span><span class="p">)</span> <span class="o">is</span> <span class="s1">&#39;:&#39;</span> <span class="o">or</span> <span class="nx">stack</span><span class="p">[</span><span class="nx">stack</span><span class="p">.</span><span class="nx">length</span> <span class="o">-</span> <span class="mi">1</span><span class="p">]</span><span class="o">?</span><span