title: Convert CamelCase to under_score_case in php __autoload()
body: <p>PHP manual <a href="http://www.php.net/manual/en/language.oop5.autoload.php" rel="nofollow noreferrer">suggests</a> to autoload classes like </p>
  
  <pre><code>function __autoload($class_name){
   require_once("some_dir/".$class_name.".php");
  }
  </code></pre>
  
  <p>and this approach works fine to load class <code>FooClass</code> saved in the file <code>my_dir/FooClass.php</code> like </p>
  
  <pre><code>class FooClass{
    //some implementation
  }
  </code></pre>
  
  <p><strong>Question</strong></p>
  
  <p>How can I make it possible to use <code>_autoload()</code> function and access <code>FooClass</code> saved in the file <code>my_dir/foo_class.php</code>?</p>