1   with TEXT_IO ; use TEXT_IO ;
    2   procedure MAIN is
                      -- SAME AS BEFORE, JUST ADDED INDENTATION TO PRINTOUT
    3     type NODE ; -- just introduce type name
    4     type NODE_PTR is access NODE ; -- define an access type
    5                                    -- ie the type of a pointer
    6     type NODE is  -- now, really define the type NODE
    7       record
    8         BF    : INTEGER      ; -- balance factor for later use
    9         LEFT  : NODE_PTR     ; -- this records predecessor
   10         RIGHT : NODE_PTR     ; -- this records sucessor
   11         NAME  : STRING(1..2) ; -- data, the "sort" key
   12         PHONE : STRING(1..2) ; -- more tag along data
   13       end record ;
   14
   15     ROOT_PTR   : NODE_PTR := new NODE'(0, null, null, "D ", "4 ") ;
   16                                  -- build a dummy root node
   17     LEFT_PTR   : NODE_PTR ;
   18     RIGHT_PTR  : NODE_PTR ;
   19
   20     DEPTH : INTEGER := 1 ; -- indentation depth
   21
   22     procedure OUTPUT(T : NODE_PTR ) is
   23       procedure INDENT is              -- new procedure inside OUTPUT
   24       begin
   25         for I in 1..DEPTH loop
   26           PUT("    ") ;
   27         end loop ;
   28       end INDENT ;
   29     begin
   30       DEPTH := DEPTH + 1 ;  -- count depth "down" upon entry
   31       if T /= null then
   32         OUTPUT(T.LEFT) ;
   33         INDENT ; PUT(T.NAME) ; PUT_LINE(T.PHONE) ;
   34         OUTPUT(T.RIGHT) ;
   35       end if ;
   36       DEPTH := DEPTH - 1 ;  -- count depth "up" upon exit
   37     end OUTPUT ;
   38
   39   begin
   40     PUT_LINE(" basic access types ") ;
        Same as previous page

 basic access types 
                A 1 
            B 2 
                C 3 
        D 4 
                E 5 
            F 6 
                G 7