[theoh]

They have a nested structure, is all I meant by "linked list". I know Haskell can deal with infinite streams (e.g. by generating the values with corecursion) but the basic "singly-linked" character remains. They aren't doubly-linked, easy to traverse in both directions: they are recursion-centric, as the article stated.

The notorious/ingenious idea of zippers exists to facilitate sane navigation and (effectively) mutation of data structures. It deals with precisely the issue of the pointers in a functional data structure pointing in inconvenient directions...