I guess I can proxy APersistentVector, but the Clojure docs [1] advise to use reify in favour to proxy whenever possible. My goal is to have my byte stream behave like a standard Clojure vector. (Parts of that stream also represent maps, and I'd like to do the same without loading them into Clojure maps, as they may be quite big.) It looks unidiomatic to me to resort to proxy to achieve that. Although maybe in the present case that's fine?
I'm just remembering that Collection is an interface and not a class, so I guess that's not too bad since I can add it to my reify. [1] http://clojure.org/datatypes Thanks, Vincent On Tuesday, 9 July 2013 20:40:43 UTC+2, Gary Trakhman wrote: > > From the lack of extending java's Collection in IPersistentVector or > associated interfaces, it seems like the intent is for every implementation > to extend (proxy) APersistentVector. Is that sufficient for what you're > trying to do? None of the methods in there are final. > > > On Tue, Jul 9, 2013 at 2:32 PM, Vincent <vhenn...@gmail.com > <javascript:>>wrote: > >> Hello, >> >> Suppose I have a byte array representing an array of integers: >> $ clojure-repl >> Clojure 1.5.1 >> user=> (def v >> (let [a (byte-array (map byte [0 0 0 1 0 2 0 3]))] >> (reify clojure.lang.IPersistentVector >> clojure.lang.Seqable >> (seq [_] (for [i (range 0 (alength a) 2)] >> (bit-or (bit-shift-left (aget a i) 8) (aget a (inc >> i)))))))) >> #'user/v >> user=> (println v) >> [0 1 2 3] >> nil >> user=> (= [0 1 2 3] v) >> ClassCastException user$fn$reify__2 cannot be cast to >> java.util.Collection clojure.lang.APersistentVector.doEquiv >> (APersistentVector.java:88) >> >> This is because doEquiv assumes that an instance of IPersistentVector >> also is an instance of Collection. While that may be true for standard >> Clojure data structures, this may not necessarily be the case for custom >> implementations. >> >> Am I really the first one to attempt something like that? Am I not >> supposed to write custom implementations of standard interfaces? Should >> that bug be raised in JIRA? >> >> Thanks, >> Vincent >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> 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+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > -- -- 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.
