-- file name chkdbl.adb, a program to test the list and list.dbl
-- packages, however, since gnat won't allow me to  
-- instantiate the io package for doubly-linked lists ,
-- intlistn.dbl.io,  I simply used the Put for singly-linked lists,
-- defined in intlistn.io, 
-- for both (there's no difference), and never needed the doubly-linked
-- list io package.
 

with intlistn.io, intlistn.dbl,text_io,int_io;	
use text_io,int_io, intlistn, intlistn.io;
procedure chkdbl is

  package intdbl renames intlistn.dbl;
   
  procedure print_msg_list( S: String; L: Pointer) is
  begin
    New_Line;
    Put(S);
    Put(L);
  end print_msg_list;

  L, DL, OneToGo, OneBefore : pointer;

begin
  L := cons(1, cons(2, cons(3, Empty)));
  print_msg_list("List L starts out with: ", L);
  DL := intdbl.cons(2, intdbl.cons(4, intdbl.cons(6, Empty)));
  print_msg_list("List DL starts out with: ", DL);
  insert(12, L, L);
  print_msg_list("should be 1 12 2 3, is: ", L);
  intdbl.insert(24, DL, DL);
  print_msg_list("should be 2 24 4 6, is: ", DL);
  put_line("IsEmpty(L)?");
  if IsEmpty(L) then put_line("yes"); else put_line("no"); end if;
  put_line("IsEmpty(DL)?");
  if IsEmpty(DL) then put_line("yes"); else put_line("no"); end if;
  OneBefore := rest(L);
  OneToGo := rest(OneBefore);
  delete(OneToGo, OneBefore, L);
  print_msg_list("should be 1 12 3, is: ", L);
  OneToGo := rest(rest(DL));
  OneBefore := intdbl.prev(OneToGo);
  intdbl.delete(OneToGo, OneBefore, DL);
  print_msg_list("should be 2 24 6, is: ", DL);
  setFirst(L, 17);
  print_msg_list("should be 17 12 3, is: ", L);
  setRest(DL, L);
  print_msg_list("should be 2 17 12 3, is: ", DL);

end chkdbl;