Re: Node to first or last element of a sequential list in module list/xlist

[Bruno Haible]

Marc Nieper-Wißkirchen wrote:
> > I don't understand. You want to use a list_node_t while adding nodes to
> > the list? This is invalid, since the comments in gl_list.h say:
> >
> >   /* Type representing the position of an element in the list, in a way
> > that
> >      is more adapted to the list implementation than a plain index.
> >      Note: It is invalidated by insertions and removals!  */
> >   typedef struct gl_list_node_impl * gl_list_node_t;
> >
> 
> It won't work with removals but it does work with insertions because
> gl_list_add_before/gl_list_add_after/... etc. all return new, valid list
> node objects.

While this may be true for the linked-list implementation, it is not true
for the array-list and other implementation. But the point of the Gnulib
list module is to allow the developer to switch to a different implementation
without changing their algorithms. [1]

Bruno

[1] https://savannah.gnu.org/forum/forum.php?forum_id=9898