So should I open a bug on this map< behavior? This also breaks composability with things like filter< because they assume that nil being returned implies a closed channel, and proceed to close their output channel...
e.g. (filter< identity (map< seq c)) will close the output channel after something like (>!! c []) On Monday, April 7, 2014 1:50:18 PM UTC-4, tbc++ wrote: > > (async/into []) is probably the closest thing to doall > > > On Mon, Apr 7, 2014 at 11:46 AM, Alejandro Ciniglio > <skia...@gmail.com<javascript:> > > wrote: > >> Sure, except you can use doall to realize the sequence from map, but >> there's no equivalent for core.async.map<. I guess you could wrap it in >> something that constantly tries to read from the output channel? >> >> On Apr 7, 2014, 1:39 PM, Timothy Baldridge wrote: >> >> That's the case with clojure.core.map as well, don't consume the lazy >> seq the side effects aren't run...in short, map is not for side effects. >> >> >> >> On Mon, Apr 7, 2014 at 11:32 AM, Alejandro Ciniglio >> <skia...@gmail.com<javascript:> >> > wrote: >> >>> Yeah, that seems to be the best practice that's promoted as well. >>> Another gotcha with this implementation is that since it's done via >>> extending the channel protocol (specifically take!), it doesn't actually >>> apply the functions effects unless someone is reading from the channel. >>> This could be an issue if you want side-effects only from the map< call. >>> >>> >>> On Monday, April 7, 2014 11:36:21 AM UTC-4, James Reeves wrote: >>> >>>> This looks like a bug to me. A lot of the internal core.async >>>> functions rely on nil values indicating the channel is closed. >>>> >>>> - James >>>> >>>> >>>> On 7 April 2014 16:26, Alejandro Ciniglio <skia...@gmail.com> wrote: >>>> >>>>> Using core.async, I've understood the convention to be that if you >>>>> take nil from a channel, that channel is closed. This seems to hold for >>>>> most cases, but I've found a corner case when using map< that lets you >>>>> pull >>>>> nil from a channel that is not closed. >>>>> >>>>> (def a (chan)) >>>>> (def c (map< seq a)) >>>>> (go (prn (<! c))) >>>>> (>!! a []) >>>>> ; => nil nil ;; [one nil is printed, one is returned] >>>>> (go (prn (<! c))) >>>>> (>!! a [1]) >>>>> ; => nil (1) >>>>> >>>>> This can be chained as well (e.g. (map< identity (map< seq a)) ), >>>>> and nils just flow through. >>>>> >>>>> From looking at the implementation, it's apparent that this happens >>>>> because the function application of map happens when taking from the >>>>> output >>>>> channel so nil is not technically on the channel, (unless it flows >>>>> through >>>>> to another map). >>>>> >>>>> Is this a bug or is my mental model of nil => closed incorrect? >>>>> >>>>> Thanks, >>>>> Alejandro >>>>> -- >>>>> 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 >>>>> --- >>>>> 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/d/optout. >>>>> >>>> >>>> -- >>> 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/d/optout. >>> >> >> >> >> -- >> “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 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 a topic in the >> Google Groups "Clojure" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/clojure/Hnjg9ovh0uA/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> clojure+u...@googlegroups.com <javascript:>. >> >> 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 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/d/optout. >> > > > > -- > “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 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.
