If you're using clojure.zip then a zipper is merely a vector with 3 specific keys (:zip/make-node, :zip/children, and :zip/branch?) in the metadata which the zipper algorithms use to manipulate and traverse the data structure. You can trivially check using something like (and (vector? z) (every? #(contains? (meta z) %) [:zip/make-node :zip/children :zip/branch?])) but there is no official way that I'm aware of that encapsulates this functionality already.
On Tuesday, June 11, 2013 2:20:38 PM UTC-7, Stefan Kamphausen wrote: > > Hi, > > > while working on some XML data extraction I got an NPE which boiled down > to calling some zipper related functions on an empty vector or nil. > > I didn't find a function in clojure.zip, clojure.data.zip or > clojure.data.zip.xml to test if an object passed to a function is actually > a zipper. Am I missing something obvious? How would you test this? I > could try to call clojure.zip/node and catch the exception, but maybe there > is a better aproach. > > > Kind regards, > stefan > -- -- 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/groups/opt_out.
