IMPLEMENTATION MODULE SingleLinkedList;

FROM  SYSTEM IMPORT ADDRESS;
FROM Storage IMPORT ALLOCATE, DEALLOCATE;

TYPE 
  ElementPtr = POINTER TO Element;
  Element    = RECORD
                 pos : CARDINAL;
                 next : ElementPtr;
                 item : ADDRESS;
              END;  
  List      = POINTER TO ListRec;            
  ListRec   = RECORD
                firstElement : ElementPtr;
                lastElement  : ElementPtr;
                homogene : BOOLEAN; (* allows or not homogene items                            *)
                CheckType : PROC;   (* procedure to check if the elements are of the same type *)
              END; 
                      

(*
PROCEDURE SearchItem ( item : ; compare : PROC ) : BOOLEAN;

  BEGIN
    ;
  END Seach;

PROCEDURE Traverse (l : List; toDo : PROC);

  BEGIN
    ;
  END Traverse;
*)
PROCEDURE Empty (l : List): BOOLEAN ;

  BEGIN
    IF l^.firstElement = NIL THEN
      RETURN TRUE
    ELSE 
     RETURN FALSE 
    END      
  END Empty;
(*
PROCEDURE RemoveItem (): BOOLEAN;

  BEGIN
    ;
  END Remove;

PROCEDURE AddItem (): BOOLEAN;

  BEGIN
    ;
  END Add;

*)

PROCEDURE DeleteAllItems (l : List);

BEGIN

END DeleteAllItems;

PROCEDURE Free ( VAR l : List);

BEGIN 
  DeleteAllItems(l);
  l^.firstElement := NIL;
  l^.homogene := TRUE ;
  l^.CheckType := NIL;
  DISPOSE (l);
END Free;

PROCEDURE Init ( VAR l : List; mode : BOOLEAN ; p : PROC );

  BEGIN
    NEW (l);
    l^.firstElement := NIL;
    l^.homogene := mode;
    l^.CheckType := p;
  END Init;

BEGIN
  (* Initialization of the SingleLinkedList structure *)
  
END SingleLinkedList.