I'll play around with agents for this when I get some more free time. I find it odd that, as the sole perceiver of an indentity, events are capable of being perceived out of order. If I were watching a line queue up in person, events are obviously "dispatched" in order through my visual perception. I trust there's a good reason it's designed this way, at any rate.
On Wed, Jul 31, 2013 at 12:25 PM, Timothy Baldridge <tbaldri...@gmail.com>wrote: > You might want to consider switching to agents (or something else) I don't > think it's possible to do what you want with refs. > > Timothy Baldridge > > > On Wed, Jul 31, 2013 at 10:08 AM, Mike Drogalis <madrush...@gmail.com>wrote: > >> Thanks for the link. :) I understand that the behavior I'm seeing is >> correct. Any idea how to achieve the desired behavior, though? >> >> >> On Wed, Jul 31, 2013 at 12:06 PM, Timothy Baldridge <tbaldri...@gmail.com >> > wrote: >> >>> The answer is here: >>> >>> >>> https://github.com/clojure/clojure/blob/master/src/jvm/clojure/lang/LockingTransaction.java#L361 >>> >>> Agents and watches are dispatched outside of the transaction locking. >>> This means that multiple transactions could be executing watches in >>> parallel, and hence execute out of order. >>> >>> Timothy Baldridge >>> >>> >>> On Wed, Jul 31, 2013 at 9:43 AM, Michael Drogalis >>> <madrush...@gmail.com>wrote: >>> >>>> I can precisely exemplify the behavior here: >>>> >>>> https://gist.github.com/MichaelDrogalis/6123177 >>>> >>>> >>>> On Wednesday, July 31, 2013 11:13:17 AM UTC-4, Michael Drogalis wrote: >>>>> >>>>> Aaron: Yep, I'm aware - and am using the value provided by the last >>>>> parameter. >>>>> >>>>> This is going to be tough to show the problem without bringing more >>>>> details of my concurrency set up. >>>>> I'm not sure if this will exhibit the problem, but this is what it >>>>> boils down to: >>>>> >>>>> https://gist.github.com/**MichaelDrogalis/6122834<https://gist.github.com/MichaelDrogalis/6122834> >>>>> >>>>> When enough threads are trying to write to the queue, the watches >>>>> triggered later can finish before watches triggered earlier. >>>>> >>>>> >>>>> On Wednesday, July 31, 2013 11:05:16 AM UTC-4, Aaron Cohen wrote: >>>>>> >>>>>> A watcher fn has 4 parameters: key, reference, old-state, new-state >>>>>> >>>>>> If you use old-state and new-state rather than the reference, you >>>>>> should not see your problem. >>>>>> >>>>>> --Aaron >>>>>> >>>>>> >>>>>> On Wed, Jul 31, 2013 at 11:00 AM, Michael Drogalis < >>>>>> madru...@gmail.com> wrote: >>>>>> >>>>>>> Problem: >>>>>>> >>>>>>> I have a ref representing a queue of people in line. >>>>>>> I add a watch to the ref to print out the contents of the queue >>>>>>> whenever it changes. >>>>>>> Naturally, and expected, the following can happen if queuing happens >>>>>>> in rapid succession: >>>>>>> >>>>>>> Queue: [] >>>>>>> <add "Mike" to queue> >>>>>>> <add "John" to queue> >>>>>>> >>>>>>> console: "Queue is Mike, John" >>>>>>> console: "Queue is Mike" >>>>>>> >>>>>>> I'd like to write a UI for this program, but I clearly can't >>>>>>> reliably render based on the result delivered >>>>>>> by the add-watch hook. What's the solution for this problem? >>>>>>> >>>>>>> -- >>>>>>> -- >>>>>>> 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. >>>> >>>> >>>> >>> >>> >>> >>> -- >>> “One of the main causes of the fall of the Roman Empire was that–lacking >>> zero–they had no way to indicate successful termination of their C >>> programs.” >>> (Robert Firth) >>> >>> -- >>> -- >>> 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 a topic in the >>> Google Groups "Clojure" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/clojure/0b5HWJE6Jx4/unsubscribe. >>> To unsubscribe from this group and all its topics, 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. >> >> >> > > > > -- > “One of the main causes of the fall of the Roman Empire was that–lacking > zero–they had no way to indicate successful termination of their C > programs.” > (Robert Firth) > > -- > -- > 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 a topic in the > Google Groups "Clojure" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/clojure/0b5HWJE6Jx4/unsubscribe. > To unsubscribe from this group and all its topics, 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. 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