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List:       haskell-cafe
Subject:    Re: putStr
From:       Hal Daume III <hdaume () ISI ! EDU>
Date:       2003-10-14 14:20:16
Message-ID: 1066141216.7474.2.camel () hal
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In addition to what Keith said, it's also guarenteed that the trace is
evaluated as soon as the function is entered.

 - Hal

On Tue, 2003-10-14 at 02:36, Ferenc Wagner wrote:
> Hal Daume III <hdaume@ISI.EDU> writes:
> 
> >> f1 :: Int -> Int
> >> f1 x 
> >>   | trace ("The initial value is " ++ show x) False = undefined
> >>   | otherwise = f2 x
> >
> > In general, the 'trace ... False = undefined' thing is
> > quite useful
> 
> How is it better than
> 
> > f1 x = trace ("The initial value is " ++ show x) $ f2 x
> 
> ?
> 
> Feri.
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-- 
 Hal Daume III                                   | hdaume@isi.edu
 "Arrest this man, he talks in maths."           | www.isi.edu/~hdaume

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