anchor.diff:  		container = class
   		public
   			constructor create();
  -			destructor destroy(); override;
  +			destructor destroy();
   			
   			function get_begin(): iterator;
   			function get_end(): iterator;
  
positive.code: 		m_link := l;
  	end;
  
  	procedure iterator.next();
  	begin
  		m_link := m_link.m_next;
  
negative.code: 		link = class
  		public
  			constructor create(data: longInt);
  			destructor destroy();
  		
  			procedure set_next(pLink: link);
  			procedure set_prev(pLink: link);
  
  