'fu'>pop</span>(<span class='no'>q</span>)</div><div class='output co'>#&gt; &lt;environment: 0x558eb1afa7a0&gt;</div><div class='input'>
 <span class='co'># pops from a stack</span>
 <span class='no'>s</span> <span class='kw'>&lt;-</span> <span class='fu'><a href='https://rdrr.io/r/utils/stack.html'>stack</a></span>()
 <span class='no'>s</span> <span class='kw'>&lt;-</span> <span class='fu'>insert</span>(<span class='no'>s</span>, <span class='fu'><a href='https://rdrr.io/r/base/list.html'>list</a></span>(