title: How to parse an ISO-8601 duration in Objective C?
body: <p>I'm looking for an easy way to parse a string that contains an ISO-8601 <strong>duration</strong> in Objective C. The result should be something usable like a <code>NSTimeInterval</code>.</p>
  
  <p>An example of an ISO-8601 duration: <code>P1DT13H24M17S</code>, which means 1 day, 13 hours, 24 minutes and 17 seconds.</p>