3 ms·

Essentially, the desirable and real elegance of recursion is the thing that got fused with the slightly simplistic notion of a linked list in the minds of the l

• chongli 10y ago
  Haskell lists are not linked lists though, they're streams. In a typical strict language any list you create goes straight on the heap. Haskell, being a lazy language, is only going to evaluate what actually needs to be evaluated. If you compose a whole bunch of functions on lists Haskell will fuse them, avoiding the allocation of all those intermediate lists. Haskell does also have a Stream data type which is similar but features a different set of tradeoffs.
  • theoh 10y ago
    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...