Thank you very much for the clarification and your incredibly fast reply :)
Leon. On Thursday, October 31, 2013 3:16:22 PM UTC+1, tbc++ wrote: > > Yes, returning a value that will be created in some sort of async fashion, > directly from a function is not idiomatic. Instead, you should be returning > channels and calling <! on them. Inside your functions you can use put! to > keep from having to decide between >! and >!!. As an example, here is how > you would use http-kit's http async client from core.async: > > (require '[org.httpkit.client :as http]) > > (defn http-get [url] > (let [c (chan)] > (http/get url > (fn [r] (put! c r))) > c)) > > Now you can do both: > (<!! (http-get "www.google.com")) > > (go (<! (http-get "www.google.com"))) > > > > Timothy Baldridge > > > > On Thu, Oct 31, 2013 at 4:34 AM, Leon Grapenthin > <[email protected]<javascript:> > > wrote: > >> Hello everyone, >> (I am posting here because I could not find a dedicated core.async group) >> >> recently I made a rather obscure bug-report (ASYNC-29). As a comment Rich >> Hickey stated that <!! and >!! should not be used in library code. I can >> now reproduce the same problem without <!!/>!! by simply derefing 50 >> undelivered promises in dedicated go-blocks (dotimes [_ 50] (go >> @(promise))). After that it is not possible to take from channels inside >> go-blocks. >> >> Now I can imagine that using promises in go-blocks is not exactly doing >> what they are designed for. I suppose that using promises within go is not >> supported. However I wonder what my options as a library creator are when I >> want to write a function that is designed to wait until it has taken a >> value from a channel. The only way I can see is to write a macro instead of >> a function, two versions. One using <!, designed for use in go-blocks, one >> using <!!, designed for use outside of go blocks. Otherwise, I don't see >> any possible way to get a value from a channel and returning it. Or am I >> missing something? >> >> Is it simply unidiomatic to return a value from a channel from a function >> body? >> >> Best regards, >> Leon. >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to [email protected]<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> [email protected] <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 [email protected] <javascript:>. >> 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 [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] 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 [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
