If Clojure's code assumes IPersistentVectors to be Collections, why doesn't IPersistentVector extend Collection? I'd consider that to be a bug.
On Wed, Jul 10, 2013 at 2:00 PM, Vincent <vhenneb...@gmail.com> wrote: > 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> 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 >>> >>> 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 >>> >>> For more options, visit this group at >>> http://groups.google.com/**group/clojure?hl=en<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. >>> >>> For more options, visit >>> https://groups.google.com/**groups/opt_out<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. > > > -- -- 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.
