title: Can't use function return value in write context error using Laravel 4
body: <p>I got an error when I try to add a private variable value to hidden input with Laravel 4</p>
  
  <pre><code>Can't use function return value in write context
  </code></pre>
  
  <p>This my code  : </p>
  
  <pre><code>$form =  Form::open(array('url' =&gt; $actionUrl))
        .= Form::hidden('storeId',  $this-&gt;_store_id)
   .=  Form::close();
  
     return $form;
  </code></pre>
  
  <p>I got this error on this line :</p>
  
  <pre><code>   .= Form::hidden('storeId',  $this-&gt;_store_id)
  </code></pre>