Apparently I oversimplified my example. In reality, I am trying to deal with a bunch of open Berkeley DB cursors which I need to combine. They cannot be processed serially. I need to ensure that all those cursors close at the end even if an exception occurs, so I need to loop over the resulting list or vector of open cursor handles. This list happens to be stored in an atom, but that is completely irrelevant to the problem I am trying to resolve: Clojure does not seem to support iteration inside catch or finally forms.
Thanks, CV On Sep 13, 5:09 pm, Kevin Downey <redc...@gmail.com> wrote: > you are using an atom as a temporary variable. please don't do that. > > (doseq [f files] > (with-open [of (open-file f)] > (do-dangerous-io of))) > > On Sun, Sep 13, 2009 at 1:05 PM, Constantine Vetoshev > > > > <gepar...@gmail.com> wrote: > > > I have some code which opens a bunch of resources (say, files), and > > needs to make sure they all get closed. Something like this: > > > (let [files (atom [])] > > (try > > (open-my-many-files files) > > ;; the files atom now refers to a vector of open file handles > > (do-dangerous-io @files) > > (finally > > (doseq [file @files] > > (.close file))))) > > > The Clojure compiler does not like this: > > error: java.lang.UnsupportedOperationException: Cannot recur from > > catch/finally > > > Does Clojure have a lower-level iteration primitive than loop and > > recur, which I can use inside exception handling code? I can obviously > > put a letfn inside the finally and use good old recursion, but I feel > > uncomfortable doing this without TCO. (Yes, I know I'm likely to run > > out of file descriptors before I run out of available stack frames, > > but this is still the wrong way to do things.) I would also very much > > prefer not to have to write and call out to Java helper classes for > > something as trivial as a loop. > > -- > And what is good, Phaedrus, > And what is not good— > Need we ask anyone to tell us these things? --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
