5. Putting it all together: Using one single object for both the list and data handling

So now that we have split the node and data logic, let's join them again! :-)

In a singly-linked list, the entire list is accessed from the "head node".
(Once assigned, the "head node" should never be modified until deletion.)
To access other nodes, a "current node" (a.k.a. "cursor") is used.
Both are needed for most list operations.

With our approach, using a set of data handling functions, we also need a structure of callback:

    /* Struct of callbacks to deal with node data */
    typedef struct node_data_fp_t
    {
      data_add_t add;
      data_set_t set;
      data_get_t get;
      data_print_t print;
      data_del_t del;
      data_cleanup_t cleanup;
    } node_data_cb_t;

So, instead of declaring both "head node" and the "current node" in a calling program, both nodes are kept in one single llwfp_t struct.
And instead of passing a callback for data handling to each call to a node operation, the struct of callbacks is used.
So the final object used from outside the library looks like this:

    typedef struct llwfp_t
    {
      node_t *head;       /* First node in list */
      node_t *current;    /* Current node in list */
      node_data_cb_t *df; /* The struct of callbacks */
    } llwfp_t;

%%% TODO EXAMPLE 5 %%%

• Example 5: One single object