title: Since when do we have such useful creators for NSArray and NSDictionary
body: <p>I discovered today that there is a much less tedious way to create arrays and dictionaries on the fly:</p>
  
  <pre><code>NSArray *myArray = @[@"one", @"two", @"three"];
  
  NSDictionary *myDict = @{@"key": @"value", @"key2": @"value2"};
  </code></pre>
  
  <p>Is this a rather new addition to the objective-c language and what is the name of these constructs?</p>