Example: orders.4gl (Function order_move)

This function moves in the ordnums array to browse the list of orders fetched by the last query.

Function order_move (orders.4gl):

  1 PRIVATE FUNCTION order_move(dir SMALLINT) RETURNS ()
  2   MESSAGE ""
  3   IF NOT order_fetch(dir) THEN
  4      IF dir == move_next THEN MESSAGE msg05 END IF
  5      IF dir == move_prev THEN MESSAGE msg06 END IF
  6   ELSE
  7      MESSAGE SFMT(msg21,orders_index,ordnums.getLength())
  8   END IF
  9 END FUNCTION

Note:

Line 1 defines the function with the direction as parameter. The function returns no value.
Line 3 calls the order_fetch function, which is doing the real move in the order list and fetches data from the database. The result value of the function is tested with an IF statement.
Lines 4 and 5 are executed when the order_fetch function returns FALSE, indicating that we could not move in the requested direction. According to the direction, we display the appropriate message to the user.
Line 7: If the order position could be moved, we display a message to the user indicating the current position in the list of orders.