[Haskell-beginners] Strange behavior

Alba Marchisio alba.marchisio at gmail.com
Mon Aug 29 08:35:54 CEST 2011


Yes, I'm interested too in this problem.
Is any body able to answer to the Luca's question?

Alba

2011/8/25 Luca Ciciriello <luca_ciciriello at hotmail.com>

> I found a strange behavior in my code
>
> Here a (very) simplified version of my code:
>
> {-# LANGUAGE PArr #-}
> {-# OPTIONS -fdph-seq #-}
>
> module Main where
>
> import Control.Parallel
> import GHC.PArr
>
> parArr :: [:String:]
> parArr = [: "1", "2", "3", "4" :]
>
> isElement :: String -> Bool
> isElement x = x `elemP` parArr
>
> main :: IO ()
> main = do
>          putStrLn $ (show . isElement) "5"
>
> The aspected result is "False" ("5" isn't a member of parArr), but the
> result I get is "True".
>
> I've compiled this code with the command:
> ghc --make -Odph -threaded Test.hs -rtsopts -o test
>
> and launched with:
> test +RTS -N2
>
> My system is MacOS X 10.7.1 with Xcode 4.1 and GHC 7.0.4 (I've found the
> same behavior on Windows).
>
> Its obvious I'm missing something. Could someone help me?
>
> Thanks.
>
> Luca.
> _______________________________________________
> Beginners mailing list
> Beginners at haskell.org
> http://www.haskell.org/mailman/listinfo/beginners
>
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