On 30 July 2012 01:34, larry google groups <lawrencecloj...@gmail.com> wrote: > > I'll ask this differently. I do not see "a" used anywhere inside of that > function. So why is it being given to that function?
I have not used send-off, but I think the answer is as follows: When you call (send-off the-agent the-function), "the-function" gets called with a single argument (which is the current value of the agent). That is why log-dumper has an argument. Of course, log-dumper does not use its argument, but it must still be there. Perhaps it should have been called "dummy". *agent* is the current agent. You said that at the end *agent* is being passed to log-dumper. This is wrong. The send-off call causes log-dumper to be called with the contents/value of the agent. Not with *agent*. > On Tuesday, July 24, 2012 1:36:27 AM UTC-4, Philip Potter wrote: >> >> "a" is the current value of the agent. *agent* is the agent itself. >> >> Remember the universal update mechanism: an agent, atom or ref is updated >> by applying a (normally) pure function to it; the function takes the current >> state and returns the new state. >> >> Phil >> >> On Jul 24, 2012 5:16 AM, "larry google groups" <lawrencecloj...@gmail.com> >> wrote: >>> >>> >>> I am confused by this blog post: >>> >>> >>> http://www.bestinclass.dk/index.clj/2009/09/php-vs-clojure-what-does-it-cost-to-be-old-school.html >>> >>> In particular, I am confuse by this function: >>> >>> (defn log-dumper >>> [a] >>> (Thread/sleep *write-delay*) >>> (let [sql-statements (let [tmp @*sql-buffer*] >>> (ref-set *sql-buffer* []) >>> tmp)] >>> (doseq [stmt sql-statements] >>> (run *mysql-connection* stmt)) >>> (send-off *agent* log-dumper))) >>> >>> >>> It looks like "a" is being passed in as an argument to the function. But >>> at the end of the function, *agent* is being passed into the function again. >>> I don't see a point in this function where "a" is magically transformed into >>> *agent*. I'm under the impression that this same agent is suppose to be >>> sent, over and over again, every 5 minutes, for all eternity, into the >>> function. But if the function is suppose to send the same agent to itself, 5 >>> minutes in the future, then I would think that if the argument is named "a" >>> then "a" is what would be send-off to the function again. >>> >>> The blog post says: >>> >>> ""send-off" myself (the *agent* is the thread) to the same function >>> again, ie. keep running." >>> >>> How does this work? How does the final line know that *agent* is the "a" >>> that was passed in as an argument? >>> >>> >>> >>> >>> >>> -- >>> 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 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 -- Michael Wood <esiot...@gmail.com> -- 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
