OK. I understand it now.<br>I think the article Claude suggested is worth a read because it shows how to hide using IORef in simple APIs.<br><br>Thanks,<br>jinwoo<br><br><br><div class="gmail_quote">On Fri, Apr 4, 2008 at 10:17 AM, Brandon S. Allbery KF8NH &lt;<a href="mailto:allbery@ece.cmu.edu">allbery@ece.cmu.edu</a>&gt; wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div class="Ih2E3d"><br>
On Apr 3, 2008, at 21:07 , Jinwoo Lee wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
But I still have to use IORef this way.<br>
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You can&#39;t escape the IORef unless you can convince the library to thread your state everywhere that it needs to be modified *and* where it needs to be read, without copying it.<div><div></div><div class="Wj3C7c"><br>

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-- <br>
brandon s. allbery [solaris,freebsd,perl,pugs,haskell] <a href="mailto:allbery@kf8nh.com" target="_blank">allbery@kf8nh.com</a><br>
system administrator [openafs,heimdal,too many hats] <a href="mailto:allbery@ece.cmu.edu" target="_blank">allbery@ece.cmu.edu</a><br>
electrical and computer engineering, carnegie mellon university &nbsp; &nbsp;KF8NH<br>
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</div></div></blockquote></div><br><br clear="all"><br>-- <br>Jinwoo Lee<br>Always remember that you are unique. Just like everyone else.