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?

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