anchor.diff:  		equal := m_link = other.m_link;
   	end;
   
  -	function list_iterator.getLink(): pLink;
  +	function list_iterator.getLink(): list_link_pointer;
   	begin
   		getLink := m_link;
   	end;
   
   	constructor list.create();
   	var
  -		link: pLink;
  +		link: list_link_pointer;
   	begin
   		new(link, create(0));
   		m_begin := list_iterator.create(link);
  
positive.code: 
  	procedure list.erase(p: list_iterator);
  	var
  		nextLink, prevLink, curLink: pLink;
  	begin
  		if p.equal(m_end) then
  			exit();
  
negative.code: 		m_prev := nil;
  	end;
  
  	procedure list_link.setNext(link: list_link_pointer);
  	begin
  		m_next := link;
  	end;
  
  	procedure list_link.setPrev(link: list_link_pointer);
  	begin
  		m_prev := link;
  	end;
  
  	constructor list_iterator.create(l: list_link_pointer);
  	begin
  		m_link := l
  	end;
  