Re: Is there an approved way for testing if something is a zipper?
Thanks for all your suggestions. Seems like a useful addition to clojure.zip to me. -- -- 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.
Is there an approved way for testing if something is a zipper?
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.
Re: Is there an approved way for testing if something is a zipper?
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.
Re: Is there an approved way for testing if something is a zipper?
I wrote a function for this in laser. https://github.com/Raynes/laser/blob/e351444a09e5c81b900767e955edf62558c33fd6/src/me/raynes/laser/zip.clj#L38 (defn zipper? Checks to see if the object has zip/make-node metadata on it (confirming it to be a zipper. [obj] (contains? (meta obj) :zip/make-node)) This is all you really need to do. Someone would have to go really out of their way to fake this, and if they do that then they probably did it on purpose and you shouldn't worry about it. 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.
