There is no point considering workarounds (but thanks either way). Every line of Clojure code near a call to `seq` has local assumptions about an immutable data structure. The implications run deep.
If this issue is going to be tackled, ArraySeq needs to be made immutable. I'll continue this discussion elsewhere, sorry for derailing the OP. Ambrose On Thu, Oct 23, 2014 at 12:21 AM, Fluid Dynamics <a2093...@trbvm.com> wrote: > On Wednesday, October 22, 2014 4:51:23 PM UTC-4, Ambrose Bonnaire-Sergeant > wrote: >> >> I missed this in the sequence spec <http://clojure.org/sequences>: When >> seq is used on native Java arrays, changes to the underlying array will be >> reflected in the seq - you must copy the source array to get full >> immutability. >> >> I understand the rationale, still quite shocking. >> >> Ambrose >> >> On Wed, Oct 22, 2014 at 3:26 PM, Jozef Wagner <jozef....@gmail.com> >> wrote: >> >>> Yes, seqs are presented as persistent collections, so this situation >>> is quite unfortunate. But in the case of seq over mutable array, I >>> think practical/performance reasons win over the correctness, which >>> would require caching of realized items. >> >> > As another poster noted, you can get caching of realized items if you > really really want it, by using (map identity the-array). And if you want a > snapshot at a particular time you had the array, regardless of how much > later a particular sequence item will be first consumed, you can copy it > upfront (with (into [] the-array), or just another array and > System/arraycopy and don't let a reference to the new array escape). > Although, mutation *while* you're taking the snapshot is harder to deal > with. You and the potential mutator would have to agree on an object (say, > the array itself) to lock. Once you have an immutable object in Clojureland > though you can dispense with explicit locking and use the STM, atoms, and > suchlike. > > -- > 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/d/optout. > -- 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/d/optout.
