title: iPhone : Unable to understand the following coding
body: <p>I have downloaded some example coding. But I found strange coding or maybe I have seen it first time. </p>
  
  <p>Can anybody help me to understand following coding?</p>
  
  <pre><code>NSArray *wordStrings = [response.spellingSuggestions wn_map: ^id (id obj) {
      return [obj word];
  }];
  </code></pre>