I recall a while ago running into this. I ended up with the following:
(defn stop?
"Returns true if there is no point continuing past the specified loc.
loc may be null or (z/end?).
This is only here because z/up returns nil rather than something (z/end? will
work with)."
[loc]
(or (nil? loc) (z/end? loc)))
and then iterating while not stop?
I also remember running into a situation where loc wasn't nil but z/node
was(!).
I can't recall the exact details but that might help...
Hussein B. writes:
> Hi,
>
> I have this structure:
>
> (def s [{"n" {"id" "a"} "d" 2 "children" [{"n" {"id" "c"} "d" 4 "children"
> []}]} {"n" {"id" "b"} "d" 3 "children" []}])
>
>
>
> And I wrote a function with zippers to traverse it:
>
> (defn traverse [col]
> (loop [z col]
> (if (= (z/next z) z)
> z
> (if (z/branch? z)
> (recur (z/next z))
> (recur (-> z println z/next))))))
>
>
> But I'm getting: NullPointerException clojure.zip/next (zip.clj:236)
>
> Any ideas?
>
> Thanks for help.
--
Sent with my mu4e
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