Thanks everyone for your answers. I understand much better now. I just had to make up some words like "rendezvous" and "pseudothread" to help me piece together these implicit concepts.
On Sunday, May 19, 2019 at 10:33:07 AM UTC-7, Brian Beckman wrote: > > The documentation for >!! reads: > > ------------------------- > clojure.core.async/>!! > ([port val]) > puts a val into port. nil values are not allowed. Will block if no > buffer space is available. Returns true unless port is already closed. > > > I have a case where I believe that the channel has no buffer, I park a > "pseudothread" in a go block reading off that channel via <!, and then > (lexically, not temporally), put to the unbuffered channel via >!!: > > (let [c (chan) ;; NO BUFFER! > d (go (<! c)) ;; park a pseudothread to read c > e (>!! c 42)] ;; blocking write to c, will unpark c's pseudothread > (println {:c-coughs-up '(this will hang (<!! c)), > :d-coughs-up (<!! d), > :what's-e e}) > (close! c) (close! d)) > > {:c-coughs-up (this will hang (<!! c)), :d-coughs-up 42, :what's-e true} > > > This case leads me to wonder whether the documentation might read > > >!! will block if there is no buffer space available *and* if there is > no *rendezvous *available, that is, no pseudothread parked waiting for <!. > > but it's more likely that I completely misunderstand core.async because I > just made up the notion of a pseudothread in my struggle to understand! > > > > -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/clojure/0b243161-9598-490e-ad81-93d53a76a21b%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.