title: What does useMethod mean here?
body: <p>One of the kool things about R is if I type the function name I get to see the implementation. But this one is confusing me, recursively:</p>
  
  <pre><code>&gt; library(xts)
  &gt; align.time
  function (x, ...) 
  {
      UseMethod("align.time")
  }
  &lt;environment: namespace:xts&gt;
  </code></pre>
  
  <p>x is an XTS object, so doesn't that mean it will call the XTS align.time method... but that is what I'm looking at! (Typing <code>xts::align.time</code> gives exactly the same response.)</p>