Comma as a separator vs. comma as a delimiter
<p>In <a href="http://www.youtube.com/watch?v=UTEqr0IlFKY#t=8m01s" rel="nofollow">this video</a>, the speaker says:</p>

<blockquote>
  <p>"Some people get confused about how commas work. They think they
  should be delimiters rather than separators. Now you can think about
  them either way."</p>
</blockquote>

<p>I don't understand the difference between a delimiter and a separator (if there is one). The implication in the video is that now (that trailing commas are valid), one can think of them as delimiters, rather than separators... </p>

<p>Btw the language in question is JavaScript. From my understanding, the comma token has two meanings:</p>

<ul>
<li>as an operator (rarely used)</li>
<li>as a separator (in argument and parameter lists, array and object literals, etc.)</li>
</ul>

<p>I'm not sure how a comma delimiter fits into this...</p>
