<div dir="ltr"><div><div><div><div><div><div><div>You can always use the Maybe type as a follows:<br><br></div>intDiv :: Integer -> Integer -> Maybe Integer<br></div>intDiv _ 0 = Nothing<br></div>intDiv n m = Just (div n m)<br>
<br></div>This allows you to pattern match results of divisions:<br><br></div>example :: Integer -> Integer -> Maybe Integer<br></div>example n m =<br></div><div> case intDiv 4 n of<br></div><div> Nothing -> Nothing<br>
</div><div> Just n' -><br> case intDiv 5 m of<br></div><div> Nothing -> Nothing<br></div><div> Just m' -> Just (n' + m')<br><br></div><div>Or even better using the do notation:<br><br>
example2 :: Integer -> Integer -> Maybe Integer<br></div><div>example2 n m = do<br></div><div> n' <- intDiv 4 n<br></div><div> m' <- intDiv 5 m<br></div><div> return (n' + m')<br><br></div>
<div>Note that example and example2 both do the same thing.<br><br></div><div>I think this is cleaner solution add NaN as a value to the Integer type.<br><br></div><div>Good luck,<br>Daniel Díaz.<br></div></div><div class="gmail_extra">
<br><br><div class="gmail_quote">On Sat, Apr 13, 2013 at 12:16 PM, Алексей Егоров <span dir="ltr"><<a href="mailto:electreg@list.ru" target="_blank">electreg@list.ru</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div><span style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">Hello haskellers,</span><br style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px"><br style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">
<span style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">is there a reason why Integer doesn't have 'NaN' as value?</span><br style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">
<span style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">I think it would be very convenient to be able to handle (1 `div` 0) as regular NaN value and not as exception.</span><br style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">
<br style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px"><span style="font-family:Arial,Tahoma,Verdana,sans-serif;font-size:13px">Thanks.</span></div>
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<br></blockquote></div><br><br clear="all"><br>-- <br><div dir="ltr"><div>E-mail sent by Daniel Díaz Casanueva<br></div><div><div><br>let f x = x in x<br></div></div></div>
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