Hi, On Oct 6, 1:23 am, MarkSwanson <mark.swanson...@gmail.com> wrote:
> I wonder if this concept will be thought of as a source of problems in > the future. Or, maybe this is just one of those fundamental Clojure > concepts you just have to learn and once you do you find you don't get > bit by it. This is a side-effect of lazyness. One has to pay close attention how the evaluation of code works. And Clojure provides enough means to tell it specifically what you want. doall is such a construct. Lazy is the default (and the right one at that), but if necessary you can tell Clojure to be eager. Vars work similar. Their notion is "thread-local". That is a "parallel universe where good Kirk and bad Kirk never meet", as Rich put it in his recent talk. The "universe" is at the moment one thread. That causes problems if you call send on an agent. That action happens on another thread, hence eventual special bindings are not in effect. And again, Clojure will provide a construct (namely bound-fn) to the programmer, so that he can express his intent. It allows to extent the universe to other threads (or later points in time). It's not finished, yet. Here the assembla ticket and a recent discussion. http://www.assembla.com/spaces/clojure/tickets/170 http://groups.google.com/group/clojure/browse_thread/thread/d4a30c8bc18ed5ab The usage would be: (defn baz [x] (map (bound-fn [_] (foo)) x)) or (def a (agent nil)) (defn baz [x] (send a (bound-fn [_] (foo)))) Note: this is not necessary in general. Eg. generating a sequence should not depend on some distant Var. Similar eg. agent actions should be pure functions of the state (and eventual other arguments to send). Sincerely Meikel --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
