title: What are "intervals" in swift ranges?
body: <p>I know there are 3 types of ranges: Range, Strides and Intervals. </p>
  
  <pre><code>var closed:ClosedInterval = 1.2...5.0
  
  var half_open:HalfOpenInterval = 1.2..&lt;5.0
  </code></pre>
  
  <p>What are intervals in swift? and what is one example of their use? </p>
  
  <p><a href="http://en.wikipedia.org/wiki/Interval_(mathematics)">http://en.wikipedia.org/wiki/Interval_(mathematics)</a></p>
  
  <p>EDIT: 
  This is what the beta 5 xcode 6 release notes says:</p>
  
  <p>• Intervals over Comparable values, which can efficiently check for containment. Intervals are 
  used for pattern matching in switch statements and by the ~= operator.</p>