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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>But since the read may block, it matters *<b>when</b>* you
perform it. For example if you print “Hello” and then read the IVar, you’ll
block after printing; but if you read the IVar and then print, the print won’t
come out. If the operation was pure (no IO) then you’d have a lot less control
over when it happened.<o:p></o:p></span></p>
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color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Simon<o:p></o:p></span></p>
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<p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:
"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;
font-family:"Tahoma","sans-serif"'> haskell-bounces@haskell.org
[mailto:haskell-bounces@haskell.org] <b>On Behalf Of </b>Lennart Augustsson<br>
<b>Sent:</b> 04 December 2007 08:19<br>
<b>To:</b> Conal Elliott<br>
<b>Cc:</b> haskell@haskell.org<br>
<b>Subject:</b> Re: [Haskell] IVars<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'>Good question. That must
be a matter of taste, because as you say the read will always produce the same
result. But it sill is a bit of a strange operation.<br>
<br>
-- Lennart<o:p></o:p></p>
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<p class=MsoNormal>On Dec 4, 2007 6:25 AM, Conal Elliott < <a
href="mailto:conal@conal.net">conal@conal.net</a>> wrote:<o:p></o:p></p>
<p class=MsoNormal>Oh. Simple enough. Thanks. <br>
<br>
Another question: why the IO in readIVar :: IVar a -> IO a, instead of
just readIVar :: IVar a -> a? After all, won't readIVar iv yield the
same result (eventually) every time it's called? <o:p></o:p></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><o:p> </o:p></p>
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<p class=MsoNormal>On Dec 3, 2007 12:29 AM, Lennart Augustsson <<a
href="mailto:lennart@augustsson.net" target="_blank">lennart@augustsson.net</a>>
wrote:<o:p></o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'>You can make them from MVars.<o:p></o:p></p>
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<p class=MsoNormal>On Dec 2, 2007 8:03 PM, Conal Elliott <<a
href="mailto:conal@conal.net" target="_blank">conal@conal.net</a>> wrote:<o:p></o:p></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'>what became of (assign-once)
IVars? afaict, they were in concurrent haskell and now aren't.<o:p></o:p></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'>_______________________________________________<br>
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