628     if ( !preg_match('/^[a-z0-9_]+$/', $filter_name) )

   628     if ( !preg_match('/^[a-z0-9_]+$/', $filter_name) )

   629     {

   629     {

   630       return false;

   630       return false;

   631     }

   631     }

   632     $this->filters[$filter_name] = $filter_function;

   632     $this->filters[$filter_name] = $filter_function;

   633   }

   634   }

   634   

   635   

   635   /**

   636   /**

   636    * Fetches a language string from the cache in RAM. If it isn't there, it will call fetch() again and then try. If it still can't find it, it will ask for the string

   637    * Fetches a language string from the cache in RAM. If it isn't there, it will call fetch() again and then try. If it still can't find it, it will ask for the string

   637    * in the default language. If even then the string can't be found, this function will return what was passed to it.

   638    * in the default language. If even then the string can't be found, this function will return what was passed to it.