The built-in vector-zip will build a tree with a different structure than
what I need.
I want build a tree as described in the first post: the node value is the
first element of the vector and the children the rest of the elements.
zipper.core> (loop [loc (tree-zipper [1 2 [3 4 5]])]
(if (z/end? loc)
(z/root loc)
(do (println (z/node loc))
(recur (z/next loc)))))
[1 2 [3 4 5]]
2
[3 4 5]
4
5
[1 2 [3 4 5]]
zipper.core> (loop [loc (z/vector-zip [1 2 [3 4 5]])]
(if (z/end? loc)
(z/root loc)
(do (println (z/node loc))
(recur (z/next loc)))))
[1 2 [3 4 5]]
1
2
[3 4 5]
3
4
5
[1 2 [3 4 5]]
On Tuesday, November 26, 2013 11:56:45 PM UTC, martin_clausen wrote:
>
> With a nested vector tree you can use the built in vector-zip function to
> create your zipper.
>
> As to the editing, the source
> code<https://github.com/clojure/clojure/blob/master/src/clj/clojure/zip.clj>
> contains
> a very similar use-case, which can be adapted to something like the
> following:
>
> (let [vz (vector-zip [1 2 [3 4 5]])]
> (loop [loc vz]
> (if (end? loc)
> (root loc)
> (recur (next (if (and (integer? (node loc)) (odd? (node loc)))
> (replace loc (* 2 (node loc)))
> loc))))))
>
> > [2 2 [6 4 10]]
>
> On Tuesday, November 26, 2013 10:50:34 PM UTC+1, dabd wrote:
>>
>> I am trying to work with a tree representation using vectors where the
>> first element is the node value and the rest are the children as suggested
>> here:
>>
>> http://grokbase.com/t/gg/clojure/12afy2cz9p/how-to-represent-trees-for-use-with-zippers
>>
>> However I am having trouble using clojure.zip/edit to change a simple
>> tree. I'd like to multiply the odd numbers by 2 in this case.
>> https://gist.github.com/dabd/7666778
>>
>> It looks like after editing the first (branch) node clojure.zip/next will
>> get to the end of the tree.
>> How can I correct this code?
>>
>> Thanks.
>>
>>
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