I wrote this article long ago which hints about this at the end: https://www.ibm.com/developerworks/library/j-treevisit/
The approach I have taken for editing trees with zippers is to do a post-walk from end to beginning - that way you're always done transforming and will not walk into your edited subtrees. The article does talk a little about how to separate navigation from transformation; it's not particularly hard. You want to start from your rightmost node, which you can get from a repeated application of zip/rightmost or last of zip/rights. Then repeatedly call prev till you reach a node without a parent at that point convert the loc to a node in the termination. I can dig up actual code for this later if you're interested. Alex On Monday, May 5, 2014 6:01:04 PM UTC-5, Pascal Germroth wrote: > > Hi, > > I'm using clojure.zip to edit a tree by visiting each location using > zip/next, possibly using zip/replace to alter the tree. > There are cases where I replace a part of the tree with another tree that > will/must not be visited, but I couldn't find a good way to skip nodes, > since > (zip/next (zip/replace loc new-subtree)) will walk right into my new tree, > and I can't use (zip/right (zip/replace loc new-subtree)) as the replaced > location might already be the rightmost. > > Is there a built-in function I missed, or a zip enhancement library I > could use? > > (defn skip > "returns the next location that is not a child of this one" > [loc] > (if (or (z/end? loc) (nil? loc)) > loc > (loop [loc loc] > (or (z/right loc) > (recur (z/up loc)))))) > > I came up with this replacement, does that seem like a good idea, or am I > using zip completely wrong (because what I really would like to do is > iterate backwards through the tree, starting at the end, using zip/prev; > but there's also no function to just jump to the end as far as I can tell) > > > Cheers, > > -- > pascal > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
