PHP Error: end - Only variables should be passed by reference

[kmindi]

As the error message suggests one correction would be:

@@ -13,7 +13,8 @@ class LClientScript extends CClientScript{
     public function registerCssFile($url, $media='')
     {
         //if the file extension is .less, use the lessparser.
-        $file_extension = end(explode('.',$url));
+        $splittedarray = explode('.',$url);
+        $file_extension = end($splittedarray);
         if($file_extension == 'less'){
             $url = $this->compileLess($url, false);
         }

But as suggested(
http://stackoverflow.com/questions/4636166/only-variables-should-be-passed-by-reference):

$file_extension = pathinfo($file_name, PATHINFO_EXTENSION);