You might find this work in progress interesting then: http://github.com/clojure/core.async
On Thu, May 30, 2013 at 3:46 PM, David Pollak <feeder.of.the.be...@gmail.com > wrote: > Paul, > > Thanks... but I want the opposite of delay. > > Basically, I do not want to consume a thread waiting for a Future to be > satisfied. I want to continue a computation on a different thread once the > Future/Promise is satisfied. Why? > > Think of a web app that's serving either a long poll or a web socket. > Basically, you don't want to consume a thread waiting for some computation > to take place. Rather, you want the computation to take place and then for > the computation of sending the result to continue/resume once the > computation has completed. Futures/Promises are excellent vehicles for > this, especially when functions close over local scope and most of the > local scope is persistant) and we use them extensively in Lift-land. > > I will move a lot of the stuff I've developed in Lift-land over to Clojure > as many of the constructs will, I believe, play as well on Clojure as they > do on Scala. > > Thanks, > > David > > > > On Thu, May 30, 2013 at 12:36 PM, Paul deGrandis <paul.degran...@gmail.com > > wrote: > >> I'm not entirely sure what you're trying to accomplish in a larger >> context, but perhaps you're looking for something like this? >> >> (delay (deref (future (and (Thread/sleep 2000) (+ 1 2))))) >> >> ... or maybe you want just `delay` >> >> Cheers, >> Paul >> >> >> >> On Thursday, May 30, 2013 6:09:02 AM UTC-7, David Pollak wrote: >> >>> Okay... I wrote my own: >>> >>> https://github.com/**projectplugh/plugh/blob/** >>> master/src/plugh/util/misc.**clj#L51<https://github.com/projectplugh/plugh/blob/master/src/plugh/util/misc.clj#L51> >>> >>> One can register for on-done and on-fail. I'll work on adding fail-fast >>> and also map (so one can transform the future and execute code when the >>> transformed future has been realized/delivered/finished). >>> >>> Thanks for your help! >>> >>> >>> >>> On Thu, May 30, 2013 at 2:17 AM, Gary Trakhman <gary.t...@gmail.com>wrote: >>> >>>> by the second future, I mean an instance of http://docs.oracle.com/** >>>> javase/6/docs/api/java/util/**concurrent/Future.html<http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/Future.html> >>>> , >>>> which just has to conform to the interface, and doesn't actually have to >>>> execute on a different thread. Clojure's 'future' function returns an >>>> instance of one of these that uses the unbounded agent thread-pool, but you >>>> would be free to return one using reify or something. >>>> >>>> https://github.com/clojure/**clojure/blob/master/src/clj/** >>>> clojure/core.clj#L6320<https://github.com/clojure/clojure/blob/master/src/clj/clojure/core.clj#L6320> >>>> >>>> >>>> On Thu, May 30, 2013 at 5:14 AM, Gary Trakhman <gary.t...@gmail.com>wrote: >>>> >>>>> Maybe an easy solution: wrap the first future in another future that >>>>> blocking-derefs, then performs your extra computation? Do an extra >>>>> 'realized?' check for the optimization you mention. That would still >>>>> consume threads in the case that it's not realized, but I think it gets >>>>> you >>>>> what you want. >>>>> >>>>> >>>>> On Thu, May 30, 2013 at 5:09 AM, Mark Engelberg >>>>> <mark.en...@gmail.com>wrote: >>>>> >>>>>> According to this article, Clojure does not yet have this facility: >>>>>> http://java.dzone.com/**articles/promises-and-futures-**clojure<http://java.dzone.com/articles/promises-and-futures-clojure> >>>>>> >>>>>> This is something that is being worked on and discussed, though: >>>>>> http://dev.clojure.org/**display/design/Promises<http://dev.clojure.org/display/design/Promises> >>>>>> https://groups.google.com/**forum/#!topic/clojure-dev/** >>>>>> 7BKQi9nWwAw/discussion<https://groups.google.com/forum/#!topic/clojure-dev/7BKQi9nWwAw/discussion> >>>>>> http://dev.clojure.org/**display/design/Async+blocks<http://dev.clojure.org/display/design/Async+blocks> >>>>>> >>>>>> I've been hearing a lot about Tellman's lamina library as a rich >>>>>> Clojure toolset for working with asynchronicity. I haven't had a need >>>>>> for >>>>>> it myself, but you might want to check it out and see if it has relevance >>>>>> to what you want to do. >>>>>> >>>>>> -- >>>>>> -- >>>>>> 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 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> >>>> . >>>> >>>> >>>> >>> >>> >>> >>> -- >>> Telegram, Simply Beautiful CMS https://telegr.am >>> Lift, the simply functional web framework http://liftweb.net >>> Follow me: http://twitter.com/dpp >>> Blog: http://goodstuff.im >>> >>> -- >> -- >> 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. >> >> >> > > > > -- > Telegram, Simply Beautiful CMS https://telegr.am > Lift, the simply functional web framework http://liftweb.net > Follow me: http://twitter.com/dpp > Blog: http://goodstuff.im > > -- > -- > 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. 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