On Tue, Mar 31, 2009 at 10:13 PM, Dan Weston <weston...@imageworks.com> wrote: > >> What I've learned: Zippers are "structured collections[1] with a >> focus". Through a Zipper you can O(1) change the value of the focused >> element: that's the fundamental property. In addition, you can change >> the focus through a series of "moving" functions. > > To clarify: there is no magic that turns a data structure into O(1) access, > just as a CPS transformation is not a magic bullet for speeding up programs. > Only the move functions (changing focus to some subset of "adjacent" > substructures) are O(1). Update functions need not be O(1). And amortized > random access time via a zipper is never less than amortized random access > of the optimal equivalent un-zippered data structure.
That's true. But, correct me if I'm wrong, updates on the focus site are O(1). Cristiano _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
