title: Why does this call to Agent#update with the capture operator work in Elixir 1.4.2?
body: <p>So I understand the capture operator in this context:</p>
  
  <pre><code>sum_it = &amp;(&amp;1 + 2)
  sum_it.(1) # result is 3
  </code></pre>
  
  <p>But I don't understand it here:</p>
  
  <pre><code># stores "Peter" where pid = #PID&lt;0.82.0&gt;
  Agent.update(pid, &amp;["Peter" | &amp;1])
  </code></pre>
  
  <p>It looks like it's turning the List into an anonymous function?  And the "&amp;1" somehow represents the tail of a list?</p>