title: Swift - iterate array of dictionaries
body: <p>Trying to find the title of each book:</p>
  
  <pre><code>var error: NSError?
      let path = NSBundle.mainBundle().pathForResource("books", ofType: "json")
      let jsonData = NSData.dataWithContentsOfFile(path, options: .DataReadingMappedIfSafe, error: nil)
      let jsonDict = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &amp;error) as NSDictionary
      let books = jsonDict["book"]
  
      var bookTitles:[String]
  
      //for bookDict:Dictionary in books {
      //    println("title: \(bookDict["title"])")
      //}
  </code></pre>
  
  <p>When I uncomment those last three lines, all hell breaks loose in Xcode6 beta3 - all text turns white, I get constant "SourceKitService Terminated" and "Editor functionality temporarily limited" popups, and I get these helpful build errors:</p>
  
  <pre><code>&lt;unknown&gt;:0: error: unable to execute command: Segmentation fault: 11
  &lt;unknown&gt;:0: error: swift frontend command failed due to signal
  </code></pre>
  
  <p>I have seriously offended the compiler here. So what is the correct way to iterate through the array of dictionaries and find the "title" property of each dict?</p>