Creates a row reference based on path.
This reference will keep pointing to the node pointed to
by path, so long as it exists. Any changes that occur on model are
propagated, and the path is updated appropriately. If
path isn't a valid path in model, then NULL is returned.
Creates a row reference based on path. This reference will keep pointing to the node pointed to by path, so long as it exists. Any changes that occur on model are propagated, and the path is updated appropriately. If path isn't a valid path in model, then NULL is returned.