title: $this -> syntax in CodeIgniter
body: <p>I am fairly new to CodeIgniter framework and PHP, and I am trying to figure out what the following source code does:</p>
  
  <pre><code>isset($this-&gt;page-&gt;data-&gt;Metadata-&gt;Metadata-&gt;View);
  </code></pre>
  
  <p>From my understanding, <code>isset()</code> checks if the variable <code>View</code> is set or not, but what confuses me is that I couldn't find <code>page</code> class (the location of the .php file that contains <code>View</code> variable) anywhere in my project folder, nor can I find <code>page</code> class in the CodeIgniter libraries. </p>
  
  <p>Can someone break down this code, and explain it in detail?  </p>