putStr

Hal Daume III hdaume at ISI.EDU
Tue Oct 14 08:20:16 EDT 2003


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 at 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.
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
-- 
 Hal Daume III                                   | hdaume at isi.edu
 "Arrest this man, he talks in maths."           | www.isi.edu/~hdaume



More information about the Haskell-Cafe mailing list